diff options
Diffstat (limited to 'tools/testing/selftests/bpf/progs/task_ls_recursion.c')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/task_ls_recursion.c | 43 |
1 files changed, 40 insertions, 3 deletions
diff --git a/tools/testing/selftests/bpf/progs/task_ls_recursion.c b/tools/testing/selftests/bpf/progs/task_ls_recursion.c index 564583dca7c8..4542dc683b44 100644 --- a/tools/testing/selftests/bpf/progs/task_ls_recursion.c +++ b/tools/testing/selftests/bpf/progs/task_ls_recursion.c @@ -5,7 +5,13 @@ #include <bpf/bpf_helpers.h> #include <bpf/bpf_tracing.h> +#ifndef EBUSY +#define EBUSY 16 +#endif + char _license[] SEC("license") = "GPL"; +int nr_del_errs = 0; +int test_pid = 0; struct { __uint(type, BPF_MAP_TYPE_TASK_STORAGE); @@ -26,6 +32,13 @@ int BPF_PROG(on_lookup) { struct task_struct *task = bpf_get_current_task_btf(); + if (!test_pid || task->pid != test_pid) + return 0; + + /* The bpf_task_storage_delete will call + * bpf_local_storage_lookup. The prog->active will + * stop the recursion. + */ bpf_task_storage_delete(&map_a, task); bpf_task_storage_delete(&map_b, task); return 0; @@ -37,11 +50,32 @@ int BPF_PROG(on_update) struct task_struct *task = bpf_get_current_task_btf(); long *ptr; + if (!test_pid || task->pid != test_pid) + return 0; + ptr = bpf_task_storage_get(&map_a, task, 0, BPF_LOCAL_STORAGE_GET_F_CREATE); - if (ptr) + /* ptr will not be NULL when it is called from + * the bpf_task_storage_get(&map_b,...F_CREATE) in + * the BPF_PROG(on_enter) below. It is because + * the value can be found in map_a and the kernel + * does not need to acquire any spin_lock. + */ + if (ptr) { + int err; + *ptr += 1; + err = bpf_task_storage_delete(&map_a, task); + if (err == -EBUSY) + nr_del_errs++; + } + /* This will still fail because map_b is empty and + * this BPF_PROG(on_update) has failed to acquire + * the percpu busy lock => meaning potential + * deadlock is detected and it will fail to create + * new storage. + */ ptr = bpf_task_storage_get(&map_b, task, 0, BPF_LOCAL_STORAGE_GET_F_CREATE); if (ptr) @@ -57,14 +91,17 @@ int BPF_PROG(on_enter, struct pt_regs *regs, long id) long *ptr; task = bpf_get_current_task_btf(); + if (!test_pid || task->pid != test_pid) + return 0; + ptr = bpf_task_storage_get(&map_a, task, 0, BPF_LOCAL_STORAGE_GET_F_CREATE); - if (ptr) + if (ptr && !*ptr) *ptr = 200; ptr = bpf_task_storage_get(&map_b, task, 0, BPF_LOCAL_STORAGE_GET_F_CREATE); - if (ptr) + if (ptr && !*ptr) *ptr = 100; return 0; } |