6.6-stable review patch. If anyone has any objections, please let me know.
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From: Hou Tao houtao1@huawei.com
[ Upstream commit 75a442581d05edaee168222ffbe00d4389785636 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/bpf/memalloc.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index d93ddac283d40..956f80ee6f5c5 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -958,6 +958,8 @@ 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); }