From 0a09a2f933c73dc76ab0b72da6855f44342a8903 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Tue, 21 Feb 2023 21:06:42 +0100 Subject: bpf: Annotate data races in bpf_local_storage There are a few cases where hlist_node is checked to be unhashed without holding the lock protecting its modification. In this case, one must use hlist_unhashed_lockless to avoid load tearing and KCSAN reports. Fix this by using lockless variant in places not protected by the lock. Since this is not prompted by any actual KCSAN reports but only from code review, I have not included a fixes tag. Cc: Martin KaFai Lau Cc: KP Singh Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20230221200646.2500777-4-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/bpf_local_storage.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 35f4138a54dc..58da17ae5124 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -51,11 +51,21 @@ owner_storage(struct bpf_local_storage_map *smap, void *owner) return map->ops->map_owner_storage_ptr(owner); } +static bool selem_linked_to_storage_lockless(const struct bpf_local_storage_elem *selem) +{ + return !hlist_unhashed_lockless(&selem->snode); +} + static bool selem_linked_to_storage(const struct bpf_local_storage_elem *selem) { return !hlist_unhashed(&selem->snode); } +static bool selem_linked_to_map_lockless(const struct bpf_local_storage_elem *selem) +{ + return !hlist_unhashed_lockless(&selem->map_node); +} + static bool selem_linked_to_map(const struct bpf_local_storage_elem *selem) { return !hlist_unhashed(&selem->map_node); @@ -174,7 +184,7 @@ static void __bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem, bool free_local_storage = false; unsigned long flags; - if (unlikely(!selem_linked_to_storage(selem))) + if (unlikely(!selem_linked_to_storage_lockless(selem))) /* selem has already been unlinked from sk */ return; @@ -208,7 +218,7 @@ void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem) struct bpf_local_storage_map_bucket *b; unsigned long flags; - if (unlikely(!selem_linked_to_map(selem))) + if (unlikely(!selem_linked_to_map_lockless(selem))) /* selem has already be unlinked from smap */ return; @@ -420,7 +430,7 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, err = check_flags(old_sdata, map_flags); if (err) return ERR_PTR(err); - if (old_sdata && selem_linked_to_storage(SELEM(old_sdata))) { + if (old_sdata && selem_linked_to_storage_lockless(SELEM(old_sdata))) { copy_map_value_locked(&smap->map, old_sdata->data, value, false); return old_sdata; -- cgit From 9db44fdd8105da00669d425acab887c668df75f6 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Sat, 25 Feb 2023 16:40:09 +0100 Subject: bpf: Support kptrs in local storage maps Enable support for kptrs in local storage maps by wiring up the freeing of these kptrs from map value. Freeing of bpf_local_storage_map is only delayed in case there are special fields, therefore bpf_selem_free_* path can also only dereference smap safely in that case. This is recorded using a bool utilizing a hole in bpF_local_storage_elem. It could have been tagged in the pointer value smap using the lowest bit (since alignment > 1), but since there was already a hole I went with the simpler option. Only the map structure freeing is delayed using RCU barriers, as the buckets aren't used when selem is being freed, so they can be freed once all readers of the bucket lists can no longer access it. Cc: Martin KaFai Lau Cc: KP Singh Cc: Paul E. McKenney Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20230225154010.391965-3-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf_local_storage.h | 6 +++++ kernel/bpf/bpf_local_storage.c | 48 +++++++++++++++++++++++++++++++++++---- kernel/bpf/syscall.c | 6 ++++- kernel/bpf/verifier.c | 12 ++++++---- 4 files changed, 63 insertions(+), 9 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index 6d37a40cd90e..0fe92986412b 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -74,6 +74,12 @@ struct bpf_local_storage_elem { struct hlist_node snode; /* Linked to bpf_local_storage */ struct bpf_local_storage __rcu *local_storage; struct rcu_head rcu; + bool can_use_smap; /* Is it safe to access smap in bpf_selem_free_* RCU + * callbacks? bpf_local_storage_map_free only + * executes rcu_barrier when there are special + * fields, this field remembers that to ensure we + * don't access already freed smap in sdata. + */ /* 8 bytes hole */ /* The data is stored in another cacheline to minimize * the number of cachelines access during a cache hit. diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 58da17ae5124..2bdd722fe293 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -85,6 +85,7 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, if (selem) { if (value) copy_map_value(&smap->map, SDATA(selem)->data, value); + /* No need to call check_and_init_map_value as memory is zero init */ return selem; } @@ -113,10 +114,25 @@ static void bpf_selem_free_rcu(struct rcu_head *rcu) struct bpf_local_storage_elem *selem; selem = container_of(rcu, struct bpf_local_storage_elem, rcu); + /* The can_use_smap bool is set whenever we need to free additional + * fields in selem data before freeing selem. bpf_local_storage_map_free + * only executes rcu_barrier to wait for RCU callbacks when it has + * special fields, hence we can only conditionally dereference smap, as + * by this time the map might have already been freed without waiting + * for our call_rcu callback if it did not have any special fields. + */ + if (selem->can_use_smap) + bpf_obj_free_fields(SDATA(selem)->smap->map.record, SDATA(selem)->data); + kfree(selem); +} + +static void bpf_selem_free_tasks_trace_rcu(struct rcu_head *rcu) +{ + /* Free directly if Tasks Trace RCU GP also implies RCU GP */ if (rcu_trace_implies_rcu_gp()) - kfree(selem); + bpf_selem_free_rcu(rcu); else - kfree_rcu(selem, rcu); + call_rcu(rcu, bpf_selem_free_rcu); } /* local_storage->lock must be held and selem->local_storage == local_storage. @@ -170,9 +186,9 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor RCU_INIT_POINTER(local_storage->cache[smap->cache_idx], NULL); if (use_trace_rcu) - call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_rcu); + call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_tasks_trace_rcu); else - kfree_rcu(selem, rcu); + call_rcu(&selem->rcu, bpf_selem_free_rcu); return free_local_storage; } @@ -240,6 +256,11 @@ void bpf_selem_link_map(struct bpf_local_storage_map *smap, RCU_INIT_POINTER(SDATA(selem)->smap, smap); hlist_add_head_rcu(&selem->map_node, &b->list); raw_spin_unlock_irqrestore(&b->lock, flags); + + /* If our data will have special fields, smap will wait for us to use + * its record in bpf_selem_free_* RCU callbacks before freeing itself. + */ + selem->can_use_smap = !IS_ERR_OR_NULL(smap->map.record); } void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool use_trace_rcu) @@ -723,6 +744,25 @@ void bpf_local_storage_map_free(struct bpf_map *map, */ synchronize_rcu(); + /* Only delay freeing of smap, buckets are not needed anymore */ kvfree(smap->buckets); + + /* When local storage has special fields, callbacks for + * bpf_selem_free_rcu and bpf_selem_free_tasks_trace_rcu will keep using + * the map BTF record, we need to execute an RCU barrier to wait for + * them as the record will be freed right after our map_free callback. + */ + if (!IS_ERR_OR_NULL(smap->map.record)) { + rcu_barrier_tasks_trace(); + /* We cannot skip rcu_barrier() when rcu_trace_implies_rcu_gp() + * is true, because while call_rcu invocation is skipped in that + * case in bpf_selem_free_tasks_trace_rcu (and all local storage + * maps pass use_trace_rcu = true), there can be call_rcu + * callbacks based on use_trace_rcu = false in the earlier while + * ((selem = ...)) loop or from bpf_local_storage_unlink_nolock + * called from owner's free path. + */ + rcu_barrier(); + } bpf_map_area_free(smap); } diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index da117a2a83b2..eb50025b03c1 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1063,7 +1063,11 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf, map->map_type != BPF_MAP_TYPE_LRU_HASH && map->map_type != BPF_MAP_TYPE_LRU_PERCPU_HASH && map->map_type != BPF_MAP_TYPE_ARRAY && - map->map_type != BPF_MAP_TYPE_PERCPU_ARRAY) { + map->map_type != BPF_MAP_TYPE_PERCPU_ARRAY && + map->map_type != BPF_MAP_TYPE_SK_STORAGE && + map->map_type != BPF_MAP_TYPE_INODE_STORAGE && + map->map_type != BPF_MAP_TYPE_TASK_STORAGE && + map->map_type != BPF_MAP_TYPE_CGRP_STORAGE) { ret = -EOPNOTSUPP; goto free_map_tab; } diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a856896e835a..bf580f246a01 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7222,22 +7222,26 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, break; case BPF_MAP_TYPE_SK_STORAGE: if (func_id != BPF_FUNC_sk_storage_get && - func_id != BPF_FUNC_sk_storage_delete) + func_id != BPF_FUNC_sk_storage_delete && + func_id != BPF_FUNC_kptr_xchg) goto error; break; case BPF_MAP_TYPE_INODE_STORAGE: if (func_id != BPF_FUNC_inode_storage_get && - func_id != BPF_FUNC_inode_storage_delete) + func_id != BPF_FUNC_inode_storage_delete && + func_id != BPF_FUNC_kptr_xchg) goto error; break; case BPF_MAP_TYPE_TASK_STORAGE: if (func_id != BPF_FUNC_task_storage_get && - func_id != BPF_FUNC_task_storage_delete) + func_id != BPF_FUNC_task_storage_delete && + func_id != BPF_FUNC_kptr_xchg) goto error; break; case BPF_MAP_TYPE_CGRP_STORAGE: if (func_id != BPF_FUNC_cgrp_storage_get && - func_id != BPF_FUNC_cgrp_storage_delete) + func_id != BPF_FUNC_cgrp_storage_delete && + func_id != BPF_FUNC_kptr_xchg) goto error; break; case BPF_MAP_TYPE_BLOOM_FILTER: -- cgit From e768e3c5aab44ee63f58649d4c8cbbb3270e5c06 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 3 Mar 2023 15:15:42 +0100 Subject: bpf: Use separate RCU callbacks for freeing selem Martin suggested that instead of using a byte in the hole (which he has a use for in his future patch) in bpf_local_storage_elem, we can dispatch a different call_rcu callback based on whether we need to free special fields in bpf_local_storage_elem data. The free path, described in commit 9db44fdd8105 ("bpf: Support kptrs in local storage maps"), only waits for call_rcu callbacks when there are special (kptrs, etc.) fields in the map value, hence it is necessary that we only access smap in this case. Therefore, dispatch different RCU callbacks based on the BPF map has a valid btf_record, which dereference and use smap's btf_record only when it is valid. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20230303141542.300068-1-memxor@gmail.com Signed-off-by: Martin KaFai Lau --- include/linux/bpf_local_storage.h | 6 --- kernel/bpf/bpf_local_storage.c | 79 ++++++++++++++++++++++++--------------- 2 files changed, 49 insertions(+), 36 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index 0fe92986412b..6d37a40cd90e 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -74,12 +74,6 @@ struct bpf_local_storage_elem { struct hlist_node snode; /* Linked to bpf_local_storage */ struct bpf_local_storage __rcu *local_storage; struct rcu_head rcu; - bool can_use_smap; /* Is it safe to access smap in bpf_selem_free_* RCU - * callbacks? bpf_local_storage_map_free only - * executes rcu_barrier when there are special - * fields, this field remembers that to ensure we - * don't access already freed smap in sdata. - */ /* 8 bytes hole */ /* The data is stored in another cacheline to minimize * the number of cachelines access during a cache hit. diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 2bdd722fe293..3d320393a12c 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -109,30 +109,36 @@ void bpf_local_storage_free_rcu(struct rcu_head *rcu) kfree_rcu(local_storage, rcu); } -static void bpf_selem_free_rcu(struct rcu_head *rcu) +static void bpf_selem_free_fields_rcu(struct rcu_head *rcu) { struct bpf_local_storage_elem *selem; + struct bpf_local_storage_map *smap; selem = container_of(rcu, struct bpf_local_storage_elem, rcu); - /* The can_use_smap bool is set whenever we need to free additional - * fields in selem data before freeing selem. bpf_local_storage_map_free - * only executes rcu_barrier to wait for RCU callbacks when it has - * special fields, hence we can only conditionally dereference smap, as - * by this time the map might have already been freed without waiting - * for our call_rcu callback if it did not have any special fields. - */ - if (selem->can_use_smap) - bpf_obj_free_fields(SDATA(selem)->smap->map.record, SDATA(selem)->data); + /* protected by the rcu_barrier*() */ + smap = rcu_dereference_protected(SDATA(selem)->smap, true); + bpf_obj_free_fields(smap->map.record, SDATA(selem)->data); kfree(selem); } -static void bpf_selem_free_tasks_trace_rcu(struct rcu_head *rcu) +static void bpf_selem_free_fields_trace_rcu(struct rcu_head *rcu) { /* Free directly if Tasks Trace RCU GP also implies RCU GP */ if (rcu_trace_implies_rcu_gp()) - bpf_selem_free_rcu(rcu); + bpf_selem_free_fields_rcu(rcu); + else + call_rcu(rcu, bpf_selem_free_fields_rcu); +} + +static void bpf_selem_free_trace_rcu(struct rcu_head *rcu) +{ + struct bpf_local_storage_elem *selem; + + selem = container_of(rcu, struct bpf_local_storage_elem, rcu); + if (rcu_trace_implies_rcu_gp()) + kfree(selem); else - call_rcu(rcu, bpf_selem_free_rcu); + kfree_rcu(selem, rcu); } /* local_storage->lock must be held and selem->local_storage == local_storage. @@ -145,6 +151,7 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor { struct bpf_local_storage_map *smap; bool free_local_storage; + struct btf_record *rec; void *owner; smap = rcu_dereference_check(SDATA(selem)->smap, bpf_rcu_lock_held()); @@ -185,10 +192,26 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor SDATA(selem)) RCU_INIT_POINTER(local_storage->cache[smap->cache_idx], NULL); - if (use_trace_rcu) - call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_tasks_trace_rcu); - else - call_rcu(&selem->rcu, bpf_selem_free_rcu); + /* A different RCU callback is chosen whenever we need to free + * additional fields in selem data before freeing selem. + * bpf_local_storage_map_free only executes rcu_barrier to wait for RCU + * callbacks when it has special fields, hence we can only conditionally + * dereference smap, as by this time the map might have already been + * freed without waiting for our call_rcu callback if it did not have + * any special fields. + */ + rec = smap->map.record; + if (use_trace_rcu) { + if (!IS_ERR_OR_NULL(rec)) + call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_fields_trace_rcu); + else + call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_trace_rcu); + } else { + if (!IS_ERR_OR_NULL(rec)) + call_rcu(&selem->rcu, bpf_selem_free_fields_rcu); + else + kfree_rcu(selem, rcu); + } return free_local_storage; } @@ -256,11 +279,6 @@ void bpf_selem_link_map(struct bpf_local_storage_map *smap, RCU_INIT_POINTER(SDATA(selem)->smap, smap); hlist_add_head_rcu(&selem->map_node, &b->list); raw_spin_unlock_irqrestore(&b->lock, flags); - - /* If our data will have special fields, smap will wait for us to use - * its record in bpf_selem_free_* RCU callbacks before freeing itself. - */ - selem->can_use_smap = !IS_ERR_OR_NULL(smap->map.record); } void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool use_trace_rcu) @@ -748,19 +766,20 @@ void bpf_local_storage_map_free(struct bpf_map *map, kvfree(smap->buckets); /* When local storage has special fields, callbacks for - * bpf_selem_free_rcu and bpf_selem_free_tasks_trace_rcu will keep using - * the map BTF record, we need to execute an RCU barrier to wait for - * them as the record will be freed right after our map_free callback. + * bpf_selem_free_fields_rcu and bpf_selem_free_fields_trace_rcu will + * keep using the map BTF record, we need to execute an RCU barrier to + * wait for them as the record will be freed right after our map_free + * callback. */ if (!IS_ERR_OR_NULL(smap->map.record)) { rcu_barrier_tasks_trace(); /* We cannot skip rcu_barrier() when rcu_trace_implies_rcu_gp() * is true, because while call_rcu invocation is skipped in that - * case in bpf_selem_free_tasks_trace_rcu (and all local storage - * maps pass use_trace_rcu = true), there can be call_rcu - * callbacks based on use_trace_rcu = false in the earlier while - * ((selem = ...)) loop or from bpf_local_storage_unlink_nolock - * called from owner's free path. + * case in bpf_selem_free_fields_trace_rcu (and all local + * storage maps pass use_trace_rcu = true), there can be + * call_rcu callbacks based on use_trace_rcu = false in the + * while ((selem = ...)) loop above or when owner's free path + * calls bpf_local_storage_unlink_nolock. */ rcu_barrier(); } -- cgit From 7490b7f1c02ef825ef98f7230662049d4a464a21 Mon Sep 17 00:00:00 2001 From: Yafang Shao Date: Sun, 5 Mar 2023 12:46:11 +0000 Subject: bpf, net: bpf_local_storage memory usage A new helper is introduced into bpf_local_storage map to calculate the memory usage. This helper is also used by other maps like bpf_cgrp_storage, bpf_inode_storage, bpf_task_storage and etc. Note that currently the dynamically allocated storage elements are not counted in the usage, since it will take extra runtime overhead in the elements update or delete path. So let's put it aside now, and implement it in the future when someone really need it. Signed-off-by: Yafang Shao Link: https://lore.kernel.org/r/20230305124615.12358-15-laoar.shao@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/bpf_local_storage.h | 1 + kernel/bpf/bpf_cgrp_storage.c | 1 + kernel/bpf/bpf_inode_storage.c | 1 + kernel/bpf/bpf_local_storage.c | 10 ++++++++++ kernel/bpf/bpf_task_storage.c | 1 + net/core/bpf_sk_storage.c | 1 + 6 files changed, 15 insertions(+) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index 6d37a40cd90e..d934248b8e81 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -164,5 +164,6 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, void *value, u64 map_flags, gfp_t gfp_flags); void bpf_local_storage_free_rcu(struct rcu_head *rcu); +u64 bpf_local_storage_map_mem_usage(const struct bpf_map *map); #endif /* _BPF_LOCAL_STORAGE_H */ diff --git a/kernel/bpf/bpf_cgrp_storage.c b/kernel/bpf/bpf_cgrp_storage.c index 6cdf6d9ed91d..9ae07aedaf23 100644 --- a/kernel/bpf/bpf_cgrp_storage.c +++ b/kernel/bpf/bpf_cgrp_storage.c @@ -221,6 +221,7 @@ const struct bpf_map_ops cgrp_storage_map_ops = { .map_update_elem = bpf_cgrp_storage_update_elem, .map_delete_elem = bpf_cgrp_storage_delete_elem, .map_check_btf = bpf_local_storage_map_check_btf, + .map_mem_usage = bpf_local_storage_map_mem_usage, .map_btf_id = &bpf_local_storage_map_btf_id[0], .map_owner_storage_ptr = cgroup_storage_ptr, }; diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c index 05f4c66c9089..43e2619c8167 100644 --- a/kernel/bpf/bpf_inode_storage.c +++ b/kernel/bpf/bpf_inode_storage.c @@ -223,6 +223,7 @@ const struct bpf_map_ops inode_storage_map_ops = { .map_update_elem = bpf_fd_inode_storage_update_elem, .map_delete_elem = bpf_fd_inode_storage_delete_elem, .map_check_btf = bpf_local_storage_map_check_btf, + .map_mem_usage = bpf_local_storage_map_mem_usage, .map_btf_id = &bpf_local_storage_map_btf_id[0], .map_owner_storage_ptr = inode_storage_ptr, }; diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 3d320393a12c..d3ba3f2db640 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -685,6 +685,16 @@ bool bpf_local_storage_unlink_nolock(struct bpf_local_storage *local_storage) return free_storage; } +u64 bpf_local_storage_map_mem_usage(const struct bpf_map *map) +{ + struct bpf_local_storage_map *smap = (struct bpf_local_storage_map *)map; + u64 usage = sizeof(*smap); + + /* The dynamically callocated selems are not counted currently. */ + usage += sizeof(*smap->buckets) * (1ULL << smap->bucket_log); + return usage; +} + struct bpf_map * bpf_local_storage_map_alloc(union bpf_attr *attr, struct bpf_local_storage_cache *cache) diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c index 1e486055a523..20f942229f3c 100644 --- a/kernel/bpf/bpf_task_storage.c +++ b/kernel/bpf/bpf_task_storage.c @@ -335,6 +335,7 @@ const struct bpf_map_ops task_storage_map_ops = { .map_update_elem = bpf_pid_task_storage_update_elem, .map_delete_elem = bpf_pid_task_storage_delete_elem, .map_check_btf = bpf_local_storage_map_check_btf, + .map_mem_usage = bpf_local_storage_map_mem_usage, .map_btf_id = &bpf_local_storage_map_btf_id[0], .map_owner_storage_ptr = task_storage_ptr, }; diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index bb378c33f542..7a36353dbc22 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -324,6 +324,7 @@ const struct bpf_map_ops sk_storage_map_ops = { .map_local_storage_charge = bpf_sk_storage_charge, .map_local_storage_uncharge = bpf_sk_storage_uncharge, .map_owner_storage_ptr = bpf_sk_storage_ptr, + .map_mem_usage = bpf_local_storage_map_mem_usage, }; const struct bpf_func_proto bpf_sk_storage_get_proto = { -- cgit From 4cbd23cc92c49173e402753cab62b8a7754ed18f Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Tue, 7 Mar 2023 22:59:20 -0800 Subject: bpf: Move a few bpf_local_storage functions to static scope This patch moves the bpf_local_storage_free_rcu() and bpf_selem_unlink_map() to static because they are not used outside of bpf_local_storage.c. Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20230308065936.1550103-2-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- include/linux/bpf_local_storage.h | 3 --- kernel/bpf/bpf_local_storage.c | 4 ++-- 2 files changed, 2 insertions(+), 5 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index d934248b8e81..502ad7093f13 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -147,8 +147,6 @@ void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool use_trace_rcu); void bpf_selem_link_map(struct bpf_local_storage_map *smap, struct bpf_local_storage_elem *selem); -void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem); - struct bpf_local_storage_elem * bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, void *value, bool charge_mem, gfp_t gfp_flags); @@ -163,7 +161,6 @@ struct bpf_local_storage_data * bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, void *value, u64 map_flags, gfp_t gfp_flags); -void bpf_local_storage_free_rcu(struct rcu_head *rcu); u64 bpf_local_storage_map_mem_usage(const struct bpf_map *map); #endif /* _BPF_LOCAL_STORAGE_H */ diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index d3ba3f2db640..1904a4245ebe 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -95,7 +95,7 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, return NULL; } -void bpf_local_storage_free_rcu(struct rcu_head *rcu) +static void bpf_local_storage_free_rcu(struct rcu_head *rcu) { struct bpf_local_storage *local_storage; @@ -251,7 +251,7 @@ void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage, hlist_add_head_rcu(&selem->snode, &local_storage->list); } -void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem) +static void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem) { struct bpf_local_storage_map *smap; struct bpf_local_storage_map_bucket *b; -- cgit From 2ffcb6fc50174d1efc8f98633eb2647d84483c68 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Tue, 7 Mar 2023 22:59:21 -0800 Subject: bpf: Refactor codes into bpf_local_storage_destroy This patch first renames bpf_local_storage_unlink_nolock to bpf_local_storage_destroy(). It better reflects that it is only used when the storage's owner (sk/task/cgrp/inode) is being kfree(). All bpf_local_storage_destroy's caller is taking the spin lock and then free the storage. This patch also moves these two steps into the bpf_local_storage_destroy. This is a preparation work for a later patch that uses bpf_mem_cache_alloc/free in the bpf_local_storage. Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20230308065936.1550103-3-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- include/linux/bpf_local_storage.h | 2 +- kernel/bpf/bpf_cgrp_storage.c | 9 +-------- kernel/bpf/bpf_inode_storage.c | 8 +------- kernel/bpf/bpf_local_storage.c | 8 ++++++-- kernel/bpf/bpf_task_storage.c | 9 +-------- net/core/bpf_sk_storage.c | 8 +------- 6 files changed, 11 insertions(+), 33 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index 502ad7093f13..5908a954ddc2 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -128,7 +128,7 @@ bpf_local_storage_lookup(struct bpf_local_storage *local_storage, struct bpf_local_storage_map *smap, bool cacheit_lockit); -bool bpf_local_storage_unlink_nolock(struct bpf_local_storage *local_storage); +void bpf_local_storage_destroy(struct bpf_local_storage *local_storage); void bpf_local_storage_map_free(struct bpf_map *map, struct bpf_local_storage_cache *cache, diff --git a/kernel/bpf/bpf_cgrp_storage.c b/kernel/bpf/bpf_cgrp_storage.c index 9ae07aedaf23..492594d69a86 100644 --- a/kernel/bpf/bpf_cgrp_storage.c +++ b/kernel/bpf/bpf_cgrp_storage.c @@ -46,8 +46,6 @@ static struct bpf_local_storage __rcu **cgroup_storage_ptr(void *owner) void bpf_cgrp_storage_free(struct cgroup *cgroup) { struct bpf_local_storage *local_storage; - bool free_cgroup_storage = false; - unsigned long flags; rcu_read_lock(); local_storage = rcu_dereference(cgroup->bpf_cgrp_storage); @@ -57,14 +55,9 @@ void bpf_cgrp_storage_free(struct cgroup *cgroup) } bpf_cgrp_storage_lock(); - raw_spin_lock_irqsave(&local_storage->lock, flags); - free_cgroup_storage = bpf_local_storage_unlink_nolock(local_storage); - raw_spin_unlock_irqrestore(&local_storage->lock, flags); + bpf_local_storage_destroy(local_storage); bpf_cgrp_storage_unlock(); rcu_read_unlock(); - - if (free_cgroup_storage) - kfree_rcu(local_storage, rcu); } static struct bpf_local_storage_data * diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c index 43e2619c8167..2d25bcfa371b 100644 --- a/kernel/bpf/bpf_inode_storage.c +++ b/kernel/bpf/bpf_inode_storage.c @@ -57,7 +57,6 @@ static struct bpf_local_storage_data *inode_storage_lookup(struct inode *inode, void bpf_inode_storage_free(struct inode *inode) { struct bpf_local_storage *local_storage; - bool free_inode_storage = false; struct bpf_storage_blob *bsb; bsb = bpf_inode(inode); @@ -72,13 +71,8 @@ void bpf_inode_storage_free(struct inode *inode) return; } - raw_spin_lock_bh(&local_storage->lock); - free_inode_storage = bpf_local_storage_unlink_nolock(local_storage); - raw_spin_unlock_bh(&local_storage->lock); + bpf_local_storage_destroy(local_storage); rcu_read_unlock(); - - if (free_inode_storage) - kfree_rcu(local_storage, rcu); } static void *bpf_fd_inode_storage_lookup_elem(struct bpf_map *map, void *key) diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 1904a4245ebe..e19f9f50a60d 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -652,11 +652,12 @@ int bpf_local_storage_map_check_btf(const struct bpf_map *map, return 0; } -bool bpf_local_storage_unlink_nolock(struct bpf_local_storage *local_storage) +void bpf_local_storage_destroy(struct bpf_local_storage *local_storage) { struct bpf_local_storage_elem *selem; bool free_storage = false; struct hlist_node *n; + unsigned long flags; /* Neither the bpf_prog nor the bpf_map's syscall * could be modifying the local_storage->list now. @@ -667,6 +668,7 @@ bool bpf_local_storage_unlink_nolock(struct bpf_local_storage *local_storage) * when unlinking elem from the local_storage->list and * the map's bucket->list. */ + raw_spin_lock_irqsave(&local_storage->lock, flags); hlist_for_each_entry_safe(selem, n, &local_storage->list, snode) { /* Always unlink from map before unlinking from * local_storage. @@ -681,8 +683,10 @@ bool bpf_local_storage_unlink_nolock(struct bpf_local_storage *local_storage) free_storage = bpf_selem_unlink_storage_nolock( local_storage, selem, false, false); } + raw_spin_unlock_irqrestore(&local_storage->lock, flags); - return free_storage; + if (free_storage) + kfree_rcu(local_storage, rcu); } u64 bpf_local_storage_map_mem_usage(const struct bpf_map *map) diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c index 20f942229f3c..4dcef28744d1 100644 --- a/kernel/bpf/bpf_task_storage.c +++ b/kernel/bpf/bpf_task_storage.c @@ -72,8 +72,6 @@ task_storage_lookup(struct task_struct *task, struct bpf_map *map, void bpf_task_storage_free(struct task_struct *task) { struct bpf_local_storage *local_storage; - bool free_task_storage = false; - unsigned long flags; rcu_read_lock(); @@ -84,14 +82,9 @@ void bpf_task_storage_free(struct task_struct *task) } bpf_task_storage_lock(); - raw_spin_lock_irqsave(&local_storage->lock, flags); - free_task_storage = bpf_local_storage_unlink_nolock(local_storage); - raw_spin_unlock_irqrestore(&local_storage->lock, flags); + bpf_local_storage_destroy(local_storage); bpf_task_storage_unlock(); rcu_read_unlock(); - - if (free_task_storage) - kfree_rcu(local_storage, rcu); } static void *bpf_pid_task_storage_lookup_elem(struct bpf_map *map, void *key) diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index 7a36353dbc22..8f56438c104b 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -49,7 +49,6 @@ static int bpf_sk_storage_del(struct sock *sk, struct bpf_map *map) void bpf_sk_storage_free(struct sock *sk) { struct bpf_local_storage *sk_storage; - bool free_sk_storage = false; rcu_read_lock(); sk_storage = rcu_dereference(sk->sk_bpf_storage); @@ -58,13 +57,8 @@ void bpf_sk_storage_free(struct sock *sk) return; } - raw_spin_lock_bh(&sk_storage->lock); - free_sk_storage = bpf_local_storage_unlink_nolock(sk_storage); - raw_spin_unlock_bh(&sk_storage->lock); + bpf_local_storage_destroy(sk_storage); rcu_read_unlock(); - - if (free_sk_storage) - kfree_rcu(sk_storage, rcu); } static void bpf_sk_storage_map_free(struct bpf_map *map) -- cgit From 62827d612ae525695799b3635a087cb49c55e977 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Tue, 7 Mar 2023 22:59:22 -0800 Subject: bpf: Remove __bpf_local_storage_map_alloc bpf_local_storage_map_alloc() is the only caller of __bpf_local_storage_map_alloc(). The remaining logic in bpf_local_storage_map_alloc() is only a one liner setting the smap->cache_idx. Remove __bpf_local_storage_map_alloc() to simplify code. Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20230308065936.1550103-4-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- kernel/bpf/bpf_local_storage.c | 63 +++++++++++++++++------------------------- 1 file changed, 26 insertions(+), 37 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index e19f9f50a60d..f7234a8d4959 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -601,40 +601,6 @@ int bpf_local_storage_map_alloc_check(union bpf_attr *attr) return 0; } -static struct bpf_local_storage_map *__bpf_local_storage_map_alloc(union bpf_attr *attr) -{ - struct bpf_local_storage_map *smap; - unsigned int i; - u32 nbuckets; - - smap = bpf_map_area_alloc(sizeof(*smap), NUMA_NO_NODE); - if (!smap) - return ERR_PTR(-ENOMEM); - bpf_map_init_from_attr(&smap->map, attr); - - nbuckets = roundup_pow_of_two(num_possible_cpus()); - /* Use at least 2 buckets, select_bucket() is undefined behavior with 1 bucket */ - nbuckets = max_t(u32, 2, nbuckets); - smap->bucket_log = ilog2(nbuckets); - - smap->buckets = bpf_map_kvcalloc(&smap->map, sizeof(*smap->buckets), - nbuckets, GFP_USER | __GFP_NOWARN); - if (!smap->buckets) { - bpf_map_area_free(smap); - return ERR_PTR(-ENOMEM); - } - - for (i = 0; i < nbuckets; i++) { - INIT_HLIST_HEAD(&smap->buckets[i].list); - raw_spin_lock_init(&smap->buckets[i].lock); - } - - smap->elem_size = offsetof(struct bpf_local_storage_elem, - sdata.data[attr->value_size]); - - return smap; -} - int bpf_local_storage_map_check_btf(const struct bpf_map *map, const struct btf *btf, const struct btf_type *key_type, @@ -704,10 +670,33 @@ bpf_local_storage_map_alloc(union bpf_attr *attr, struct bpf_local_storage_cache *cache) { struct bpf_local_storage_map *smap; + unsigned int i; + u32 nbuckets; + + smap = bpf_map_area_alloc(sizeof(*smap), NUMA_NO_NODE); + if (!smap) + return ERR_PTR(-ENOMEM); + bpf_map_init_from_attr(&smap->map, attr); + + nbuckets = roundup_pow_of_two(num_possible_cpus()); + /* Use at least 2 buckets, select_bucket() is undefined behavior with 1 bucket */ + nbuckets = max_t(u32, 2, nbuckets); + smap->bucket_log = ilog2(nbuckets); - smap = __bpf_local_storage_map_alloc(attr); - if (IS_ERR(smap)) - return ERR_CAST(smap); + smap->buckets = bpf_map_kvcalloc(&smap->map, sizeof(*smap->buckets), + nbuckets, GFP_USER | __GFP_NOWARN); + if (!smap->buckets) { + bpf_map_area_free(smap); + return ERR_PTR(-ENOMEM); + } + + for (i = 0; i < nbuckets; i++) { + INIT_HLIST_HEAD(&smap->buckets[i].list); + raw_spin_lock_init(&smap->buckets[i].lock); + } + + smap->elem_size = offsetof(struct bpf_local_storage_elem, + sdata.data[attr->value_size]); smap->cache_idx = bpf_local_storage_cache_idx_get(cache); return &smap->map; -- cgit From 121f31f3e00dfc1acbca43f6f35779e050b56cfc Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Tue, 7 Mar 2023 22:59:23 -0800 Subject: bpf: Remove the preceding __ from __bpf_selem_unlink_storage __bpf_selem_unlink_storage is taking the spin lock and there is no name collision also. Having the preceding '__' is confusing when reviewing the later patch. Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20230308065936.1550103-5-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- kernel/bpf/bpf_local_storage.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index f7234a8d4959..70df8dcb2066 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -216,8 +216,8 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor return free_local_storage; } -static void __bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem, - bool use_trace_rcu) +static void bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem, + bool use_trace_rcu) { struct bpf_local_storage *local_storage; bool free_local_storage = false; @@ -288,7 +288,7 @@ void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool use_trace_rcu) * the local_storage. */ bpf_selem_unlink_map(selem); - __bpf_selem_unlink_storage(selem, use_trace_rcu); + bpf_selem_unlink_storage(selem, use_trace_rcu); } /* If cacheit_lockit is false, this lookup function is lockless */ -- cgit From fc6652aab6ad545de70b772550da9043d0b47f1c Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Tue, 7 Mar 2023 22:59:24 -0800 Subject: bpf: Remember smap in bpf_local_storage This patch remembers which smap triggers the allocation of a 'struct bpf_local_storage' object. The local_storage is allocated during the very first selem added to the owner. The smap pointer is needed when using the bpf_mem_cache_free in a later patch because it needs to free to the correct smap's bpf_mem_alloc object. When a selem is being removed, it needs to check if it is the selem that triggers the creation of the local_storage. If it is, the local_storage->smap pointer will be reset to NULL. This NULL reset is done under the local_storage->lock in bpf_selem_unlink_storage_nolock() when a selem is being removed. Also note that the local_storage may not go away even local_storage->smap is NULL because there may be other selem still stored in the local_storage. Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20230308065936.1550103-6-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- include/linux/bpf_local_storage.h | 1 + kernel/bpf/bpf_local_storage.c | 4 ++++ 2 files changed, 5 insertions(+) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index 5908a954ddc2..613b1805ed9f 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -83,6 +83,7 @@ struct bpf_local_storage_elem { struct bpf_local_storage { struct bpf_local_storage_data __rcu *cache[BPF_LOCAL_STORAGE_CACHE_SIZE]; + struct bpf_local_storage_map __rcu *smap; struct hlist_head list; /* List of bpf_local_storage_elem */ void *owner; /* The object that owns the above "list" of * bpf_local_storage_elem. diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 70df8dcb2066..5585dbfd9c66 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -213,6 +213,9 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor kfree_rcu(selem, rcu); } + if (rcu_access_pointer(local_storage->smap) == smap) + RCU_INIT_POINTER(local_storage->smap, NULL); + return free_local_storage; } @@ -368,6 +371,7 @@ int bpf_local_storage_alloc(void *owner, goto uncharge; } + RCU_INIT_POINTER(storage->smap, smap); INIT_HLIST_HEAD(&storage->list); raw_spin_lock_init(&storage->lock); storage->owner = owner; -- cgit From a47eabf216f77cb6f22ceb38d46f1bb95968579c Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Tue, 7 Mar 2023 22:59:25 -0800 Subject: bpf: Repurpose use_trace_rcu to reuse_now in bpf_local_storage This patch re-purpose the use_trace_rcu to mean if the freed memory can be reused immediately or not. The use_trace_rcu is renamed to reuse_now. Other than the boolean test is reversed, it should be a no-op. The following explains the reason for the rename and how it will be used in a later patch. In a later patch, bpf_mem_cache_alloc/free will be used in the bpf_local_storage. The bpf mem allocator will reuse the freed memory immediately. Some of the free paths in bpf_local_storage does not support memory to be reused immediately. These paths are the "delete" elem cases from the bpf_*_storage_delete() helper and the map_delete_elem() syscall. Note that "delete" elem before the owner's (sk/task/cgrp/inode) lifetime ended is not the common usage for the local storage. The common free path, bpf_local_storage_destroy(), can reuse the memory immediately. This common path means the storage stays with its owner until the owner is destroyed. The above mentioned "delete" elem paths that cannot reuse immediately always has the 'use_trace_rcu == true'. The cases that is safe for immediate reuse always have 'use_trace_rcu == false'. Instead of adding another arg in a later patch, this patch re-purpose this arg to reuse_now and have the test logic reversed. In a later patch, 'reuse_now == true' will free to the bpf_mem_cache_free() where the memory can be reused immediately. 'reuse_now == false' will go through the call_rcu_tasks_trace(). Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20230308065936.1550103-7-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- include/linux/bpf_local_storage.h | 2 +- kernel/bpf/bpf_cgrp_storage.c | 2 +- kernel/bpf/bpf_inode_storage.c | 2 +- kernel/bpf/bpf_local_storage.c | 24 ++++++++++++------------ kernel/bpf/bpf_task_storage.c | 2 +- net/core/bpf_sk_storage.c | 2 +- 6 files changed, 17 insertions(+), 17 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index 613b1805ed9f..18a31add2255 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -143,7 +143,7 @@ int bpf_local_storage_map_check_btf(const struct bpf_map *map, void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage, struct bpf_local_storage_elem *selem); -void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool use_trace_rcu); +void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now); void bpf_selem_link_map(struct bpf_local_storage_map *smap, struct bpf_local_storage_elem *selem); diff --git a/kernel/bpf/bpf_cgrp_storage.c b/kernel/bpf/bpf_cgrp_storage.c index 492594d69a86..c975cacdd16b 100644 --- a/kernel/bpf/bpf_cgrp_storage.c +++ b/kernel/bpf/bpf_cgrp_storage.c @@ -121,7 +121,7 @@ static int cgroup_storage_delete(struct cgroup *cgroup, struct bpf_map *map) if (!sdata) return -ENOENT; - bpf_selem_unlink(SELEM(sdata), true); + bpf_selem_unlink(SELEM(sdata), false); return 0; } diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c index 2d25bcfa371b..ad2ab0187e45 100644 --- a/kernel/bpf/bpf_inode_storage.c +++ b/kernel/bpf/bpf_inode_storage.c @@ -122,7 +122,7 @@ static int inode_storage_delete(struct inode *inode, struct bpf_map *map) if (!sdata) return -ENOENT; - bpf_selem_unlink(SELEM(sdata), true); + bpf_selem_unlink(SELEM(sdata), false); return 0; } diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 5585dbfd9c66..70c34a948c3c 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -147,7 +147,7 @@ static void bpf_selem_free_trace_rcu(struct rcu_head *rcu) */ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_storage, struct bpf_local_storage_elem *selem, - bool uncharge_mem, bool use_trace_rcu) + bool uncharge_mem, bool reuse_now) { struct bpf_local_storage_map *smap; bool free_local_storage; @@ -201,7 +201,7 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor * any special fields. */ rec = smap->map.record; - if (use_trace_rcu) { + if (!reuse_now) { if (!IS_ERR_OR_NULL(rec)) call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_fields_trace_rcu); else @@ -220,7 +220,7 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor } static void bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem, - bool use_trace_rcu) + bool reuse_now) { struct bpf_local_storage *local_storage; bool free_local_storage = false; @@ -235,11 +235,11 @@ static void bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem, raw_spin_lock_irqsave(&local_storage->lock, flags); if (likely(selem_linked_to_storage(selem))) free_local_storage = bpf_selem_unlink_storage_nolock( - local_storage, selem, true, use_trace_rcu); + local_storage, selem, true, reuse_now); raw_spin_unlock_irqrestore(&local_storage->lock, flags); if (free_local_storage) { - if (use_trace_rcu) + if (!reuse_now) call_rcu_tasks_trace(&local_storage->rcu, bpf_local_storage_free_rcu); else @@ -284,14 +284,14 @@ void bpf_selem_link_map(struct bpf_local_storage_map *smap, raw_spin_unlock_irqrestore(&b->lock, flags); } -void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool use_trace_rcu) +void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now) { /* Always unlink from map before unlinking from local_storage * because selem will be freed after successfully unlinked from * the local_storage. */ bpf_selem_unlink_map(selem); - bpf_selem_unlink_storage(selem, use_trace_rcu); + bpf_selem_unlink_storage(selem, reuse_now); } /* If cacheit_lockit is false, this lookup function is lockless */ @@ -538,7 +538,7 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, if (old_sdata) { bpf_selem_unlink_map(SELEM(old_sdata)); bpf_selem_unlink_storage_nolock(local_storage, SELEM(old_sdata), - false, true); + false, false); } unlock: @@ -651,7 +651,7 @@ void bpf_local_storage_destroy(struct bpf_local_storage *local_storage) * of the loop will set the free_cgroup_storage to true. */ free_storage = bpf_selem_unlink_storage_nolock( - local_storage, selem, false, false); + local_storage, selem, false, true); } raw_spin_unlock_irqrestore(&local_storage->lock, flags); @@ -745,7 +745,7 @@ void bpf_local_storage_map_free(struct bpf_map *map, migrate_disable(); this_cpu_inc(*busy_counter); } - bpf_selem_unlink(selem, false); + bpf_selem_unlink(selem, true); if (busy_counter) { this_cpu_dec(*busy_counter); migrate_enable(); @@ -783,8 +783,8 @@ void bpf_local_storage_map_free(struct bpf_map *map, /* We cannot skip rcu_barrier() when rcu_trace_implies_rcu_gp() * is true, because while call_rcu invocation is skipped in that * case in bpf_selem_free_fields_trace_rcu (and all local - * storage maps pass use_trace_rcu = true), there can be - * call_rcu callbacks based on use_trace_rcu = false in the + * storage maps pass reuse_now = false), there can be + * call_rcu callbacks based on reuse_now = true in the * while ((selem = ...)) loop above or when owner's free path * calls bpf_local_storage_unlink_nolock. */ diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c index 4dcef28744d1..c88cc04c17c1 100644 --- a/kernel/bpf/bpf_task_storage.c +++ b/kernel/bpf/bpf_task_storage.c @@ -168,7 +168,7 @@ static int task_storage_delete(struct task_struct *task, struct bpf_map *map, if (!nobusy) return -EBUSY; - bpf_selem_unlink(SELEM(sdata), true); + bpf_selem_unlink(SELEM(sdata), false); return 0; } diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index 8f56438c104b..a5f185b8e50a 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -40,7 +40,7 @@ static int bpf_sk_storage_del(struct sock *sk, struct bpf_map *map) if (!sdata) return -ENOENT; - bpf_selem_unlink(SELEM(sdata), true); + bpf_selem_unlink(SELEM(sdata), false); return 0; } -- cgit From c609981342dca634e5dea8c6ca175b6533581261 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Tue, 7 Mar 2023 22:59:26 -0800 Subject: bpf: Remove bpf_selem_free_fields*_rcu This patch removes the bpf_selem_free_fields*_rcu. The bpf_obj_free_fields() can be done before the call_rcu_trasks_trace() and kfree_rcu(). It is needed when a later patch uses bpf_mem_cache_alloc/free. In bpf hashtab, bpf_obj_free_fields() is also called before calling bpf_mem_cache_free. The discussion can be found in https://lore.kernel.org/bpf/f67021ee-21d9-bfae-6134-4ca542fab843@linux.dev/ Acked-by: Kumar Kartikeya Dwivedi Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20230308065936.1550103-8-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- kernel/bpf/bpf_local_storage.c | 67 ++++-------------------------------------- 1 file changed, 5 insertions(+), 62 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 70c34a948c3c..715deaaefe13 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -109,27 +109,6 @@ static void bpf_local_storage_free_rcu(struct rcu_head *rcu) kfree_rcu(local_storage, rcu); } -static void bpf_selem_free_fields_rcu(struct rcu_head *rcu) -{ - struct bpf_local_storage_elem *selem; - struct bpf_local_storage_map *smap; - - selem = container_of(rcu, struct bpf_local_storage_elem, rcu); - /* protected by the rcu_barrier*() */ - smap = rcu_dereference_protected(SDATA(selem)->smap, true); - bpf_obj_free_fields(smap->map.record, SDATA(selem)->data); - kfree(selem); -} - -static void bpf_selem_free_fields_trace_rcu(struct rcu_head *rcu) -{ - /* Free directly if Tasks Trace RCU GP also implies RCU GP */ - if (rcu_trace_implies_rcu_gp()) - bpf_selem_free_fields_rcu(rcu); - else - call_rcu(rcu, bpf_selem_free_fields_rcu); -} - static void bpf_selem_free_trace_rcu(struct rcu_head *rcu) { struct bpf_local_storage_elem *selem; @@ -151,7 +130,6 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor { struct bpf_local_storage_map *smap; bool free_local_storage; - struct btf_record *rec; void *owner; smap = rcu_dereference_check(SDATA(selem)->smap, bpf_rcu_lock_held()); @@ -192,26 +170,11 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor SDATA(selem)) RCU_INIT_POINTER(local_storage->cache[smap->cache_idx], NULL); - /* A different RCU callback is chosen whenever we need to free - * additional fields in selem data before freeing selem. - * bpf_local_storage_map_free only executes rcu_barrier to wait for RCU - * callbacks when it has special fields, hence we can only conditionally - * dereference smap, as by this time the map might have already been - * freed without waiting for our call_rcu callback if it did not have - * any special fields. - */ - rec = smap->map.record; - if (!reuse_now) { - if (!IS_ERR_OR_NULL(rec)) - call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_fields_trace_rcu); - else - call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_trace_rcu); - } else { - if (!IS_ERR_OR_NULL(rec)) - call_rcu(&selem->rcu, bpf_selem_free_fields_rcu); - else - kfree_rcu(selem, rcu); - } + bpf_obj_free_fields(smap->map.record, SDATA(selem)->data); + if (!reuse_now) + call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_trace_rcu); + else + kfree_rcu(selem, rcu); if (rcu_access_pointer(local_storage->smap) == smap) RCU_INIT_POINTER(local_storage->smap, NULL); @@ -769,26 +732,6 @@ void bpf_local_storage_map_free(struct bpf_map *map, */ synchronize_rcu(); - /* Only delay freeing of smap, buckets are not needed anymore */ kvfree(smap->buckets); - - /* When local storage has special fields, callbacks for - * bpf_selem_free_fields_rcu and bpf_selem_free_fields_trace_rcu will - * keep using the map BTF record, we need to execute an RCU barrier to - * wait for them as the record will be freed right after our map_free - * callback. - */ - if (!IS_ERR_OR_NULL(smap->map.record)) { - rcu_barrier_tasks_trace(); - /* We cannot skip rcu_barrier() when rcu_trace_implies_rcu_gp() - * is true, because while call_rcu invocation is skipped in that - * case in bpf_selem_free_fields_trace_rcu (and all local - * storage maps pass reuse_now = false), there can be - * call_rcu callbacks based on reuse_now = true in the - * while ((selem = ...)) loop above or when owner's free path - * calls bpf_local_storage_unlink_nolock. - */ - rcu_barrier(); - } bpf_map_area_free(smap); } -- cgit From f8ccf30c179ec1ac16654f6e6ceb40cce1530b91 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Tue, 7 Mar 2023 22:59:27 -0800 Subject: bpf: Add bpf_selem_free_rcu callback Add bpf_selem_free_rcu() callback to do the kfree() instead of using kfree_rcu. It is a preparation work for using bpf_mem_cache_alloc/free in a later patch. Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20230308065936.1550103-9-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- kernel/bpf/bpf_local_storage.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 715deaaefe13..146e9caeda96 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -109,15 +109,20 @@ static void bpf_local_storage_free_rcu(struct rcu_head *rcu) kfree_rcu(local_storage, rcu); } -static void bpf_selem_free_trace_rcu(struct rcu_head *rcu) +static void bpf_selem_free_rcu(struct rcu_head *rcu) { struct bpf_local_storage_elem *selem; selem = container_of(rcu, struct bpf_local_storage_elem, rcu); + kfree(selem); +} + +static void bpf_selem_free_trace_rcu(struct rcu_head *rcu) +{ if (rcu_trace_implies_rcu_gp()) - kfree(selem); + bpf_selem_free_rcu(rcu); else - kfree_rcu(selem, rcu); + call_rcu(rcu, bpf_selem_free_rcu); } /* local_storage->lock must be held and selem->local_storage == local_storage. @@ -174,7 +179,7 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor if (!reuse_now) call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_trace_rcu); else - kfree_rcu(selem, rcu); + call_rcu(&selem->rcu, bpf_selem_free_rcu); if (rcu_access_pointer(local_storage->smap) == smap) RCU_INIT_POINTER(local_storage->smap, NULL); -- cgit From c0d63f309186d8492577c67c67984c714b6b72bc Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Tue, 7 Mar 2023 22:59:28 -0800 Subject: bpf: Add bpf_selem_free() This patch refactors the selem freeing logic into bpf_selem_free(). It is a preparation work for a later patch using bpf_mem_cache_alloc/free. The other kfree(selem) cases are also changed to bpf_selem_free(..., reuse_now = true). Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20230308065936.1550103-10-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- include/linux/bpf_local_storage.h | 4 ++++ kernel/bpf/bpf_local_storage.c | 21 ++++++++++++++------- net/core/bpf_sk_storage.c | 2 +- 3 files changed, 19 insertions(+), 8 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index 18a31add2255..a34f61467a2f 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -152,6 +152,10 @@ struct bpf_local_storage_elem * bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, void *value, bool charge_mem, gfp_t gfp_flags); +void bpf_selem_free(struct bpf_local_storage_elem *selem, + struct bpf_local_storage_map *smap, + bool reuse_now); + int bpf_local_storage_alloc(void *owner, struct bpf_local_storage_map *smap, diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 146e9caeda96..512943aac435 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -125,6 +125,17 @@ static void bpf_selem_free_trace_rcu(struct rcu_head *rcu) call_rcu(rcu, bpf_selem_free_rcu); } +void bpf_selem_free(struct bpf_local_storage_elem *selem, + struct bpf_local_storage_map *smap, + bool reuse_now) +{ + bpf_obj_free_fields(smap->map.record, SDATA(selem)->data); + if (!reuse_now) + call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_trace_rcu); + else + call_rcu(&selem->rcu, bpf_selem_free_rcu); +} + /* local_storage->lock must be held and selem->local_storage == local_storage. * The caller must ensure selem->smap is still valid to be * dereferenced for its smap->elem_size and smap->cache_idx. @@ -175,11 +186,7 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor SDATA(selem)) RCU_INIT_POINTER(local_storage->cache[smap->cache_idx], NULL); - bpf_obj_free_fields(smap->map.record, SDATA(selem)->data); - if (!reuse_now) - call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_trace_rcu); - else - call_rcu(&selem->rcu, bpf_selem_free_rcu); + bpf_selem_free(selem, smap, reuse_now); if (rcu_access_pointer(local_storage->smap) == smap) RCU_INIT_POINTER(local_storage->smap, NULL); @@ -423,7 +430,7 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, err = bpf_local_storage_alloc(owner, smap, selem, gfp_flags); if (err) { - kfree(selem); + bpf_selem_free(selem, smap, true); mem_uncharge(smap, owner, smap->elem_size); return ERR_PTR(err); } @@ -517,7 +524,7 @@ unlock_err: raw_spin_unlock_irqrestore(&local_storage->lock, flags); if (selem) { mem_uncharge(smap, owner, smap->elem_size); - kfree(selem); + bpf_selem_free(selem, smap, true); } return ERR_PTR(err); } diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index a5f185b8e50a..24c3dc0d62e5 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -197,7 +197,7 @@ int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk) } else { ret = bpf_local_storage_alloc(newsk, smap, copy_selem, GFP_ATOMIC); if (ret) { - kfree(copy_selem); + bpf_selem_free(copy_selem, smap, true); atomic_sub(smap->elem_size, &newsk->sk_omem_alloc); bpf_map_put(map); -- cgit From 1288aaa2786b1e58c9e88e53f7654d520ebe0f3b Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Tue, 7 Mar 2023 22:59:29 -0800 Subject: bpf: Add bpf_local_storage_rcu callback The existing bpf_local_storage_free_rcu is renamed to bpf_local_storage_free_trace_rcu. A new bpf_local_storage_rcu callback is added to do the kfree instead of using kfree_rcu. It is a preparation work for a later patch using bpf_mem_cache_alloc/free. Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20230308065936.1550103-11-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- kernel/bpf/bpf_local_storage.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 512943aac435..0fbc477c8b27 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -99,14 +99,19 @@ static void bpf_local_storage_free_rcu(struct rcu_head *rcu) { struct bpf_local_storage *local_storage; + local_storage = container_of(rcu, struct bpf_local_storage, rcu); + kfree(local_storage); +} + +static void bpf_local_storage_free_trace_rcu(struct rcu_head *rcu) +{ /* If RCU Tasks Trace grace period implies RCU grace period, do * kfree(), else do kfree_rcu(). */ - local_storage = container_of(rcu, struct bpf_local_storage, rcu); if (rcu_trace_implies_rcu_gp()) - kfree(local_storage); + bpf_local_storage_free_rcu(rcu); else - kfree_rcu(local_storage, rcu); + call_rcu(rcu, bpf_local_storage_free_rcu); } static void bpf_selem_free_rcu(struct rcu_head *rcu) @@ -216,9 +221,9 @@ static void bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem, if (free_local_storage) { if (!reuse_now) call_rcu_tasks_trace(&local_storage->rcu, - bpf_local_storage_free_rcu); + bpf_local_storage_free_trace_rcu); else - kfree_rcu(local_storage, rcu); + call_rcu(&local_storage->rcu, bpf_local_storage_free_rcu); } } @@ -631,7 +636,7 @@ void bpf_local_storage_destroy(struct bpf_local_storage *local_storage) raw_spin_unlock_irqrestore(&local_storage->lock, flags); if (free_storage) - kfree_rcu(local_storage, rcu); + call_rcu(&local_storage->rcu, bpf_local_storage_free_rcu); } u64 bpf_local_storage_map_mem_usage(const struct bpf_map *map) -- cgit From 7e30a8477b0bdd13dfd0b24e4f32b26d22b96e6c Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Tue, 7 Mar 2023 22:59:30 -0800 Subject: bpf: Add bpf_local_storage_free() This patch refactors local_storage freeing logic into bpf_local_storage_free(). It is a preparation work for a later patch that uses bpf_mem_cache_alloc/free. The other kfree(local_storage) cases are also changed to bpf_local_storage_free(..., reuse_now = true). Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20230308065936.1550103-12-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- kernel/bpf/bpf_local_storage.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 0fbc477c8b27..351d991694cb 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -114,6 +114,16 @@ static void bpf_local_storage_free_trace_rcu(struct rcu_head *rcu) call_rcu(rcu, bpf_local_storage_free_rcu); } +static void bpf_local_storage_free(struct bpf_local_storage *local_storage, + bool reuse_now) +{ + if (!reuse_now) + call_rcu_tasks_trace(&local_storage->rcu, + bpf_local_storage_free_trace_rcu); + else + call_rcu(&local_storage->rcu, bpf_local_storage_free_rcu); +} + static void bpf_selem_free_rcu(struct rcu_head *rcu) { struct bpf_local_storage_elem *selem; @@ -218,13 +228,8 @@ static void bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem, local_storage, selem, true, reuse_now); raw_spin_unlock_irqrestore(&local_storage->lock, flags); - if (free_local_storage) { - if (!reuse_now) - call_rcu_tasks_trace(&local_storage->rcu, - bpf_local_storage_free_trace_rcu); - else - call_rcu(&local_storage->rcu, bpf_local_storage_free_rcu); - } + if (free_local_storage) + bpf_local_storage_free(local_storage, reuse_now); } void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage, @@ -391,7 +396,7 @@ int bpf_local_storage_alloc(void *owner, return 0; uncharge: - kfree(storage); + bpf_local_storage_free(storage, true); mem_uncharge(smap, owner, sizeof(*storage)); return err; } @@ -636,7 +641,7 @@ void bpf_local_storage_destroy(struct bpf_local_storage *local_storage) raw_spin_unlock_irqrestore(&local_storage->lock, flags); if (free_storage) - call_rcu(&local_storage->rcu, bpf_local_storage_free_rcu); + bpf_local_storage_free(local_storage, true); } u64 bpf_local_storage_map_mem_usage(const struct bpf_map *map) -- cgit From 08a7ce384e33e53e0732c500a8af67a73f8fceca Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 22 Mar 2023 14:52:43 -0700 Subject: bpf: Use bpf_mem_cache_alloc/free in bpf_local_storage_elem This patch uses bpf_mem_alloc for the task and cgroup local storage that the bpf prog can easily get a hold of the storage owner's PTR_TO_BTF_ID. eg. bpf_get_current_task_btf() can be used in some of the kmalloc code path which will cause deadlock/recursion. bpf_mem_cache_alloc is deadlock free and will solve a legit use case in [1]. For sk storage, its batch creation benchmark shows a few percent regression when the sk create/destroy batch size is larger than 32. The sk creation/destruction happens much more often and depends on external traffic. Considering it is hypothetical to be able to cause deadlock with sk storage, it can cross the bridge to use bpf_mem_alloc till a legit (ie. useful) use case comes up. For inode storage, bpf_local_storage_destroy() is called before waiting for a rcu gp and its memory cannot be reused immediately. inode stays with kmalloc/kfree after the rcu [or tasks_trace] gp. A 'bool bpf_ma' argument is added to bpf_local_storage_map_alloc(). Only task and cgroup storage have 'bpf_ma == true' which means to use bpf_mem_cache_alloc/free(). This patch only changes selem to use bpf_mem_alloc for task and cgroup. The next patch will change the local_storage to use bpf_mem_alloc also for task and cgroup. Here is some more details on the changes: * memory allocation: After bpf_mem_cache_alloc(), the SDATA(selem)->data is zero-ed because bpf_mem_cache_alloc() could return a reused selem. It is to keep the existing bpf_map_kzalloc() behavior. Only SDATA(selem)->data is zero-ed. SDATA(selem)->data is the visible part to the bpf prog. No need to use zero_map_value() to do the zeroing because bpf_selem_free(..., reuse_now = true) ensures no bpf prog is using the selem before returning the selem through bpf_mem_cache_free(). For the internal fields of selem, they will be initialized when linking to the new smap and the new local_storage. When 'bpf_ma == false', nothing changes in this patch. It will stay with the bpf_map_kzalloc(). * memory free: The bpf_selem_free() and bpf_selem_free_rcu() are modified to handle the bpf_ma == true case. For the common selem free path where its owner is also being destroyed, the mem is freed in bpf_local_storage_destroy(), the owner (task and cgroup) has gone through a rcu gp. The memory can be reused immediately, so bpf_local_storage_destroy() will call bpf_selem_free(..., reuse_now = true) which will do bpf_mem_cache_free() for immediate reuse consideration. An exception is the delete elem code path. The delete elem code path is called from the helper bpf_*_storage_delete() and the syscall bpf_map_delete_elem(). This path is an unusual case for local storage because the common use case is to have the local storage staying with its owner life time so that the bpf prog and the user space does not have to monitor the owner's destruction. For the delete elem path, the selem cannot be reused immediately because there could be bpf prog using it. It will call bpf_selem_free(..., reuse_now = false) and it will wait for a rcu tasks trace gp before freeing the elem. The rcu callback is changed to do bpf_mem_cache_raw_free() instead of kfree(). When 'bpf_ma == false', it should be the same as before. __bpf_selem_free() is added to do the kfree_rcu and call_tasks_trace_rcu(). A few words on the 'reuse_now == true'. When 'reuse_now == true', it is still racing with bpf_local_storage_map_free which is under rcu protection, so it still needs to wait for a rcu gp instead of kfree(). Otherwise, the selem may be reused by slab for a totally different struct while the bpf_local_storage_map_free() is still using it (as a rcu reader). For the inode case, there may be other rcu readers also. In short, when bpf_ma == false and reuse_now == true => vanilla rcu. [1]: https://lore.kernel.org/bpf/20221118190109.1512674-1-namhyung@kernel.org/ Cc: Namhyung Kim Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20230322215246.1675516-3-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- include/linux/bpf_local_storage.h | 6 ++- kernel/bpf/bpf_cgrp_storage.c | 2 +- kernel/bpf/bpf_inode_storage.c | 2 +- kernel/bpf/bpf_local_storage.c | 95 +++++++++++++++++++++++++++++++++++---- kernel/bpf/bpf_task_storage.c | 2 +- net/core/bpf_sk_storage.c | 2 +- 6 files changed, 95 insertions(+), 14 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index a34f61467a2f..30efbcab2798 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -13,6 +13,7 @@ #include #include #include +#include #include #define BPF_LOCAL_STORAGE_CACHE_SIZE 16 @@ -55,6 +56,8 @@ struct bpf_local_storage_map { u32 bucket_log; u16 elem_size; u16 cache_idx; + struct bpf_mem_alloc selem_ma; + bool bpf_ma; }; struct bpf_local_storage_data { @@ -122,7 +125,8 @@ int bpf_local_storage_map_alloc_check(union bpf_attr *attr); struct bpf_map * bpf_local_storage_map_alloc(union bpf_attr *attr, - struct bpf_local_storage_cache *cache); + struct bpf_local_storage_cache *cache, + bool bpf_ma); struct bpf_local_storage_data * bpf_local_storage_lookup(struct bpf_local_storage *local_storage, diff --git a/kernel/bpf/bpf_cgrp_storage.c b/kernel/bpf/bpf_cgrp_storage.c index f5b016a5484d..d17d5b694668 100644 --- a/kernel/bpf/bpf_cgrp_storage.c +++ b/kernel/bpf/bpf_cgrp_storage.c @@ -149,7 +149,7 @@ static int notsupp_get_next_key(struct bpf_map *map, void *key, void *next_key) static struct bpf_map *cgroup_storage_map_alloc(union bpf_attr *attr) { - return bpf_local_storage_map_alloc(attr, &cgroup_cache); + return bpf_local_storage_map_alloc(attr, &cgroup_cache, true); } static void cgroup_storage_map_free(struct bpf_map *map) diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c index 9a5f05151898..e17ad581b9be 100644 --- a/kernel/bpf/bpf_inode_storage.c +++ b/kernel/bpf/bpf_inode_storage.c @@ -199,7 +199,7 @@ static int notsupp_get_next_key(struct bpf_map *map, void *key, static struct bpf_map *inode_storage_map_alloc(union bpf_attr *attr) { - return bpf_local_storage_map_alloc(attr, &inode_cache); + return bpf_local_storage_map_alloc(attr, &inode_cache, false); } static void inode_storage_map_free(struct bpf_map *map) diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 351d991694cb..309ea727a5cb 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -80,8 +80,24 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, if (charge_mem && mem_charge(smap, owner, smap->elem_size)) return NULL; - selem = bpf_map_kzalloc(&smap->map, smap->elem_size, - gfp_flags | __GFP_NOWARN); + if (smap->bpf_ma) { + migrate_disable(); + selem = bpf_mem_cache_alloc_flags(&smap->selem_ma, gfp_flags); + migrate_enable(); + if (selem) + /* Keep the original bpf_map_kzalloc behavior + * before started using the bpf_mem_cache_alloc. + * + * No need to use zero_map_value. The bpf_selem_free() + * only does bpf_mem_cache_free when there is + * no other bpf prog is using the selem. + */ + memset(SDATA(selem)->data, 0, smap->map.value_size); + } else { + selem = bpf_map_kzalloc(&smap->map, smap->elem_size, + gfp_flags | __GFP_NOWARN); + } + if (selem) { if (value) copy_map_value(&smap->map, SDATA(selem)->data, value); @@ -124,12 +140,34 @@ static void bpf_local_storage_free(struct bpf_local_storage *local_storage, call_rcu(&local_storage->rcu, bpf_local_storage_free_rcu); } +/* rcu tasks trace callback for bpf_ma == false */ +static void __bpf_selem_free_trace_rcu(struct rcu_head *rcu) +{ + struct bpf_local_storage_elem *selem; + + selem = container_of(rcu, struct bpf_local_storage_elem, rcu); + if (rcu_trace_implies_rcu_gp()) + kfree(selem); + else + kfree_rcu(selem, rcu); +} + +/* Handle bpf_ma == false */ +static void __bpf_selem_free(struct bpf_local_storage_elem *selem, + bool vanilla_rcu) +{ + if (vanilla_rcu) + kfree_rcu(selem, rcu); + else + call_rcu_tasks_trace(&selem->rcu, __bpf_selem_free_trace_rcu); +} + static void bpf_selem_free_rcu(struct rcu_head *rcu) { struct bpf_local_storage_elem *selem; selem = container_of(rcu, struct bpf_local_storage_elem, rcu); - kfree(selem); + bpf_mem_cache_raw_free(selem); } static void bpf_selem_free_trace_rcu(struct rcu_head *rcu) @@ -145,10 +183,23 @@ void bpf_selem_free(struct bpf_local_storage_elem *selem, bool reuse_now) { bpf_obj_free_fields(smap->map.record, SDATA(selem)->data); - if (!reuse_now) + + if (!smap->bpf_ma) { + __bpf_selem_free(selem, reuse_now); + return; + } + + if (!reuse_now) { call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_trace_rcu); - else - call_rcu(&selem->rcu, bpf_selem_free_rcu); + } else { + /* Instead of using the vanilla call_rcu(), + * bpf_mem_cache_free will be able to reuse selem + * immediately. + */ + migrate_disable(); + bpf_mem_cache_free(&smap->selem_ma, selem); + migrate_enable(); + } } /* local_storage->lock must be held and selem->local_storage == local_storage. @@ -654,13 +705,25 @@ u64 bpf_local_storage_map_mem_usage(const struct bpf_map *map) return usage; } +/* When bpf_ma == true, the bpf_mem_alloc is used to allocate and free memory. + * A deadlock free allocator is useful for storage that the bpf prog can easily + * get a hold of the owner PTR_TO_BTF_ID in any context. eg. bpf_get_current_task_btf. + * The task and cgroup storage fall into this case. The bpf_mem_alloc reuses + * memory immediately. To be reuse-immediate safe, the owner destruction + * code path needs to go through a rcu grace period before calling + * bpf_local_storage_destroy(). + * + * When bpf_ma == false, the kmalloc and kfree are used. + */ struct bpf_map * bpf_local_storage_map_alloc(union bpf_attr *attr, - struct bpf_local_storage_cache *cache) + struct bpf_local_storage_cache *cache, + bool bpf_ma) { struct bpf_local_storage_map *smap; unsigned int i; u32 nbuckets; + int err; smap = bpf_map_area_alloc(sizeof(*smap), NUMA_NO_NODE); if (!smap) @@ -675,8 +738,8 @@ bpf_local_storage_map_alloc(union bpf_attr *attr, smap->buckets = bpf_map_kvcalloc(&smap->map, sizeof(*smap->buckets), nbuckets, GFP_USER | __GFP_NOWARN); if (!smap->buckets) { - bpf_map_area_free(smap); - return ERR_PTR(-ENOMEM); + err = -ENOMEM; + goto free_smap; } for (i = 0; i < nbuckets; i++) { @@ -687,8 +750,20 @@ bpf_local_storage_map_alloc(union bpf_attr *attr, smap->elem_size = offsetof(struct bpf_local_storage_elem, sdata.data[attr->value_size]); + smap->bpf_ma = bpf_ma; + if (bpf_ma) { + err = bpf_mem_alloc_init(&smap->selem_ma, smap->elem_size, false); + if (err) + goto free_smap; + } + smap->cache_idx = bpf_local_storage_cache_idx_get(cache); return &smap->map; + +free_smap: + kvfree(smap->buckets); + bpf_map_area_free(smap); + return ERR_PTR(err); } void bpf_local_storage_map_free(struct bpf_map *map, @@ -754,6 +829,8 @@ void bpf_local_storage_map_free(struct bpf_map *map, */ synchronize_rcu(); + if (smap->bpf_ma) + bpf_mem_alloc_destroy(&smap->selem_ma); kvfree(smap->buckets); bpf_map_area_free(smap); } diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c index ab5bd1ef58c4..d1af0c8f9ce4 100644 --- a/kernel/bpf/bpf_task_storage.c +++ b/kernel/bpf/bpf_task_storage.c @@ -309,7 +309,7 @@ static int notsupp_get_next_key(struct bpf_map *map, void *key, void *next_key) static struct bpf_map *task_storage_map_alloc(union bpf_attr *attr) { - return bpf_local_storage_map_alloc(attr, &task_cache); + return bpf_local_storage_map_alloc(attr, &task_cache, true); } static void task_storage_map_free(struct bpf_map *map) diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index cb0f5a105b89..085025c7130a 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -68,7 +68,7 @@ static void bpf_sk_storage_map_free(struct bpf_map *map) static struct bpf_map *bpf_sk_storage_map_alloc(union bpf_attr *attr) { - return bpf_local_storage_map_alloc(attr, &sk_cache); + return bpf_local_storage_map_alloc(attr, &sk_cache, false); } static int notsupp_get_next_key(struct bpf_map *map, void *key, -- cgit From 6ae9d5e99e1dd26babdd9502759fa25a3fd348ad Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 22 Mar 2023 14:52:44 -0700 Subject: bpf: Use bpf_mem_cache_alloc/free for bpf_local_storage This patch uses bpf_mem_cache_alloc/free for allocating and freeing bpf_local_storage for task and cgroup storage. The changes are similar to the previous patch. A few things that worth to mention for bpf_local_storage: The local_storage is freed when the last selem is deleted. Before deleting a selem from local_storage, it needs to retrieve the local_storage->smap because the bpf_selem_unlink_storage_nolock() may have set it to NULL. Note that local_storage->smap may have already been NULL when the selem created this local_storage has been removed. In this case, call_rcu will be used to free the local_storage. Also, the bpf_ma (true or false) value is needed before calling bpf_local_storage_free(). The bpf_ma can either be obtained from the local_storage->smap (if available) or any of its selem's smap. A new helper check_storage_bpf_ma() is added to obtain bpf_ma for a deleting bpf_local_storage. When bpf_local_storage_alloc getting a reused memory, all fields are either in the correct values or will be initialized. 'cache[]' must already be all NULLs. 'list' must be empty. Others will be initialized. Cc: Namhyung Kim Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20230322215246.1675516-4-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- include/linux/bpf_local_storage.h | 1 + kernel/bpf/bpf_local_storage.c | 130 +++++++++++++++++++++++++++++++++----- 2 files changed, 116 insertions(+), 15 deletions(-) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index 30efbcab2798..173ec7f43ed1 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -57,6 +57,7 @@ struct bpf_local_storage_map { u16 elem_size; u16 cache_idx; struct bpf_mem_alloc selem_ma; + struct bpf_mem_alloc storage_ma; bool bpf_ma; }; diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 309ea727a5cb..dab2ff4c99d9 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -111,33 +111,74 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, return NULL; } +/* rcu tasks trace callback for bpf_ma == false */ +static void __bpf_local_storage_free_trace_rcu(struct rcu_head *rcu) +{ + struct bpf_local_storage *local_storage; + + /* If RCU Tasks Trace grace period implies RCU grace period, do + * kfree(), else do kfree_rcu(). + */ + local_storage = container_of(rcu, struct bpf_local_storage, rcu); + if (rcu_trace_implies_rcu_gp()) + kfree(local_storage); + else + kfree_rcu(local_storage, rcu); +} + static void bpf_local_storage_free_rcu(struct rcu_head *rcu) { struct bpf_local_storage *local_storage; local_storage = container_of(rcu, struct bpf_local_storage, rcu); - kfree(local_storage); + bpf_mem_cache_raw_free(local_storage); } static void bpf_local_storage_free_trace_rcu(struct rcu_head *rcu) { - /* If RCU Tasks Trace grace period implies RCU grace period, do - * kfree(), else do kfree_rcu(). - */ if (rcu_trace_implies_rcu_gp()) bpf_local_storage_free_rcu(rcu); else call_rcu(rcu, bpf_local_storage_free_rcu); } +/* Handle bpf_ma == false */ +static void __bpf_local_storage_free(struct bpf_local_storage *local_storage, + bool vanilla_rcu) +{ + if (vanilla_rcu) + kfree_rcu(local_storage, rcu); + else + call_rcu_tasks_trace(&local_storage->rcu, + __bpf_local_storage_free_trace_rcu); +} + static void bpf_local_storage_free(struct bpf_local_storage *local_storage, - bool reuse_now) + struct bpf_local_storage_map *smap, + bool bpf_ma, bool reuse_now) { - if (!reuse_now) + if (!bpf_ma) { + __bpf_local_storage_free(local_storage, reuse_now); + return; + } + + if (!reuse_now) { call_rcu_tasks_trace(&local_storage->rcu, bpf_local_storage_free_trace_rcu); - else + return; + } + + if (smap) { + migrate_disable(); + bpf_mem_cache_free(&smap->storage_ma, local_storage); + migrate_enable(); + } else { + /* smap could be NULL if the selem that triggered + * this 'local_storage' creation had been long gone. + * In this case, directly do call_rcu(). + */ call_rcu(&local_storage->rcu, bpf_local_storage_free_rcu); + } } /* rcu tasks trace callback for bpf_ma == false */ @@ -260,11 +301,47 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor return free_local_storage; } +static bool check_storage_bpf_ma(struct bpf_local_storage *local_storage, + struct bpf_local_storage_map *storage_smap, + struct bpf_local_storage_elem *selem) +{ + + struct bpf_local_storage_map *selem_smap; + + /* local_storage->smap may be NULL. If it is, get the bpf_ma + * from any selem in the local_storage->list. The bpf_ma of all + * local_storage and selem should have the same value + * for the same map type. + * + * If the local_storage->list is already empty, the caller will not + * care about the bpf_ma value also because the caller is not + * responsibile to free the local_storage. + */ + + if (storage_smap) + return storage_smap->bpf_ma; + + if (!selem) { + struct hlist_node *n; + + n = rcu_dereference_check(hlist_first_rcu(&local_storage->list), + bpf_rcu_lock_held()); + if (!n) + return false; + + selem = hlist_entry(n, struct bpf_local_storage_elem, snode); + } + selem_smap = rcu_dereference_check(SDATA(selem)->smap, bpf_rcu_lock_held()); + + return selem_smap->bpf_ma; +} + static void bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem, bool reuse_now) { + struct bpf_local_storage_map *storage_smap; struct bpf_local_storage *local_storage; - bool free_local_storage = false; + bool bpf_ma, free_local_storage = false; unsigned long flags; if (unlikely(!selem_linked_to_storage_lockless(selem))) @@ -273,6 +350,10 @@ static void bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem, local_storage = rcu_dereference_check(selem->local_storage, bpf_rcu_lock_held()); + storage_smap = rcu_dereference_check(local_storage->smap, + bpf_rcu_lock_held()); + bpf_ma = check_storage_bpf_ma(local_storage, storage_smap, selem); + raw_spin_lock_irqsave(&local_storage->lock, flags); if (likely(selem_linked_to_storage(selem))) free_local_storage = bpf_selem_unlink_storage_nolock( @@ -280,7 +361,7 @@ static void bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem, raw_spin_unlock_irqrestore(&local_storage->lock, flags); if (free_local_storage) - bpf_local_storage_free(local_storage, reuse_now); + bpf_local_storage_free(local_storage, storage_smap, bpf_ma, reuse_now); } void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage, @@ -400,8 +481,15 @@ int bpf_local_storage_alloc(void *owner, if (err) return err; - storage = bpf_map_kzalloc(&smap->map, sizeof(*storage), - gfp_flags | __GFP_NOWARN); + if (smap->bpf_ma) { + migrate_disable(); + storage = bpf_mem_cache_alloc_flags(&smap->storage_ma, gfp_flags); + migrate_enable(); + } else { + storage = bpf_map_kzalloc(&smap->map, sizeof(*storage), + gfp_flags | __GFP_NOWARN); + } + if (!storage) { err = -ENOMEM; goto uncharge; @@ -447,7 +535,7 @@ int bpf_local_storage_alloc(void *owner, return 0; uncharge: - bpf_local_storage_free(storage, true); + bpf_local_storage_free(storage, smap, smap->bpf_ma, true); mem_uncharge(smap, owner, sizeof(*storage)); return err; } @@ -660,11 +748,15 @@ int bpf_local_storage_map_check_btf(const struct bpf_map *map, void bpf_local_storage_destroy(struct bpf_local_storage *local_storage) { + struct bpf_local_storage_map *storage_smap; struct bpf_local_storage_elem *selem; - bool free_storage = false; + bool bpf_ma, free_storage = false; struct hlist_node *n; unsigned long flags; + storage_smap = rcu_dereference_check(local_storage->smap, bpf_rcu_lock_held()); + bpf_ma = check_storage_bpf_ma(local_storage, storage_smap, NULL); + /* Neither the bpf_prog nor the bpf_map's syscall * could be modifying the local_storage->list now. * Thus, no elem can be added to or deleted from the @@ -692,7 +784,7 @@ void bpf_local_storage_destroy(struct bpf_local_storage *local_storage) raw_spin_unlock_irqrestore(&local_storage->lock, flags); if (free_storage) - bpf_local_storage_free(local_storage, true); + bpf_local_storage_free(local_storage, storage_smap, bpf_ma, true); } u64 bpf_local_storage_map_mem_usage(const struct bpf_map *map) @@ -755,6 +847,12 @@ bpf_local_storage_map_alloc(union bpf_attr *attr, err = bpf_mem_alloc_init(&smap->selem_ma, smap->elem_size, false); if (err) goto free_smap; + + err = bpf_mem_alloc_init(&smap->storage_ma, sizeof(struct bpf_local_storage), false); + if (err) { + bpf_mem_alloc_destroy(&smap->selem_ma); + goto free_smap; + } } smap->cache_idx = bpf_local_storage_cache_idx_get(cache); @@ -829,8 +927,10 @@ void bpf_local_storage_map_free(struct bpf_map *map, */ synchronize_rcu(); - if (smap->bpf_ma) + if (smap->bpf_ma) { bpf_mem_alloc_destroy(&smap->selem_ma); + bpf_mem_alloc_destroy(&smap->storage_ma); + } kvfree(smap->buckets); bpf_map_area_free(smap); } -- cgit From 10fd5f70c397782a97f411f25bfb312ea92b55bc Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Wed, 12 Apr 2023 10:12:52 -0700 Subject: bpf: Handle NULL in bpf_local_storage_free. During OOM bpf_local_storage_alloc() may fail to allocate 'storage' and call to bpf_local_storage_free() with NULL pointer will cause a crash like: [ 271718.917646] BUG: kernel NULL pointer dereference, address: 00000000000000a0 [ 271719.019620] RIP: 0010:call_rcu+0x2d/0x240 [ 271719.216274] bpf_local_storage_alloc+0x19e/0x1e0 [ 271719.250121] bpf_local_storage_update+0x33b/0x740 Fixes: 7e30a8477b0b ("bpf: Add bpf_local_storage_free()") Signed-off-by: Alexei Starovoitov Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20230412171252.15635-1-alexei.starovoitov@gmail.com --- kernel/bpf/bpf_local_storage.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel/bpf/bpf_local_storage.c') diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index dab2ff4c99d9..47d9948d768f 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -157,6 +157,9 @@ static void bpf_local_storage_free(struct bpf_local_storage *local_storage, struct bpf_local_storage_map *smap, bool bpf_ma, bool reuse_now) { + if (!local_storage) + return; + if (!bpf_ma) { __bpf_local_storage_free(local_storage, reuse_now); return; -- cgit