bpf: use kvzmalloc to allocate BPF verifier environment

[ 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>

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 60db311480d0a95ad5353ae365bf9b7d6dc2b368..931611d2273699af9b6d0943ba10b1df0bf7d1ed 100644 (file)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -12564,7 +12564,7 @@ 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;
@@ -12755,6 +12755,6 @@ err_unlock:
                mutex_unlock(&bpf_verifier_lock);
        vfree(env->insn_aux_data);
 err_free_env:
-       kfree(env);
+       kvfree(env);
        return ret;
 }