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authorHou Tao <[email protected]>2022-02-02 14:01:58 +0800
committerAndrii Nakryiko <[email protected]>2022-02-02 23:15:24 -0800
commitb293dcc473d22a62dc6d78de2b15e4f49515db56 (patch)
tree284d9f6552a276acc56f3263694f5b23084fecca
parentb7892f7d5cb2b8187c603dd8ea3a7c44059ccfc2 (diff)
bpf: Use VM_MAP instead of VM_ALLOC for ringbuf
After commit 2fd3fb0be1d1 ("kasan, vmalloc: unpoison VM_ALLOC pages after mapping"), non-VM_ALLOC mappings will be marked as accessible in __get_vm_area_node() when KASAN is enabled. But now the flag for ringbuf area is VM_ALLOC, so KASAN will complain out-of-bound access after vmap() returns. Because the ringbuf area is created by mapping allocated pages, so use VM_MAP instead. After the change, info in /proc/vmallocinfo also changes from [start]-[end] 24576 ringbuf_map_alloc+0x171/0x290 vmalloc user to [start]-[end] 24576 ringbuf_map_alloc+0x171/0x290 vmap user Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it") Reported-by: [email protected] Signed-off-by: Hou Tao <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
-rw-r--r--kernel/bpf/ringbuf.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c
index 638d7fd7b375..710ba9de12ce 100644
--- a/kernel/bpf/ringbuf.c
+++ b/kernel/bpf/ringbuf.c
@@ -104,7 +104,7 @@ static struct bpf_ringbuf *bpf_ringbuf_area_alloc(size_t data_sz, int numa_node)
}
rb = vmap(pages, nr_meta_pages + 2 * nr_data_pages,
- VM_ALLOC | VM_USERMAP, PAGE_KERNEL);
+ VM_MAP | VM_USERMAP, PAGE_KERNEL);
if (rb) {
kmemleak_not_leak(pages);
rb->pages = pages;