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bpf: Add missed allocation hint for bpf_mem_cache_alloc_flags()

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bpf_mem_cache_alloc_flags() may call __alloc() directly when there is no
free object in free list, but it doesn't initialize the allocation hint
for the returned pointer. It may lead to bad memory dereference when
freeing the pointer, so fix it by initializing the allocation hint.

Fixes: 822fb26bdb55 ("bpf: Add a hint to allocated objects.")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20231111043821.2258513-1-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Hou Tao 2023-11-11 12:38:21 +08:00 committed by Alexei Starovoitov
parent c0c6bde586
commit 75a442581d
1 changed files with 2 additions and 0 deletions
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2
kernel/bpf/memalloc.c
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@ -978,6 +978,8 @@ void notrace *bpf_mem_cache_alloc_flags(struct bpf_mem_alloc *ma, gfp_t flags)
memcg = get_memcg(c);
old_memcg = set_active_memcg(memcg);
ret = __alloc(c, NUMA_NO_NODE, GFP_KERNEL | __GFP_NOWARN | __GFP_ACCOUNT);
if (ret)
*(struct bpf_mem_cache **)ret = c;
set_active_memcg(old_memcg);
mem_cgroup_put(memcg);
}