Commit 75a44258 authored by Hou Tao's avatar Hou Tao Committed by Alexei Starovoitov
Browse files

bpf: Add missed allocation hint for bpf_mem_cache_alloc_flags() 



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: 822fb26b ("bpf: Add a hint to allocated objects.")
Signed-off-by: default avatarHou Tao <houtao1@huawei.com>
Acked-by: default avatarYonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20231111043821.2258513-1-houtao@huaweicloud.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent c0c6bde5

kernel/bpf/memalloc.c

+2 −0
Original line number Diff line number Diff line
@@ -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);

	}