4.19-stable review patch. If anyone has any objections, please let me know.
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From: Rik van Riel riel@surriel.com
[ Upstream commit 434247637c66e1be2bc71a9987d4c3f0d8672387 ]
The kzmalloc call in bpf_check can fail when memory is very fragmented, which in turn can lead to an OOM kill.
Use kvzmalloc to fall back to vmalloc when memory is too fragmented to allocate an order 3 sized bpf verifier environment.
Admittedly this is not a very common case, and only happens on systems where memory has already been squeezed close to the limit, but this does not seem like much of a hot path, and it's a simple enough fix.
Signed-off-by: Rik van Riel riel@surriel.com Reviewed-by: Shakeel Butt shakeel.butt@linux.dev Link: https://lore.kernel.org/r/20241008170735.16766766@imladris.surriel.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/bpf/verifier.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a48de55f5630e..de0926cff8352 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6446,7 +6446,7 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr) /* 'struct bpf_verifier_env' can be global, but since it's not small, * allocate/free it every time bpf_check() is called */ - env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL); + env = kvzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL); if (!env) return -ENOMEM; log = &env->log; @@ -6573,6 +6573,6 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr) mutex_unlock(&bpf_verifier_lock); vfree(env->insn_aux_data); err_free_env: - kfree(env); + kvfree(env); return ret; }