From: Tobias Tefke <tobias.tefke@gmail.com>
To: tobias.tefke@tutanota.com, ast@kernel.org, daniel@iogearbox.net
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] bpf: remove unnecessary condition in bpf_check()
Date: Mon, 9 Jul 2018 13:48:37 +0200 [thread overview]
Message-ID: <20180709114837.23864-1-tobias.tefke@tutanota.com> (raw)
In the label skip_full_check the function sanitize_dead_code()
is being called if the return value equals zero.
After that call there is another condition checking
if the return value equals zero.
If this condition evaluates to true,
check_max_stack_depth() is being called.
However, sanitize_dead_code() has no return value.
Therefore the return value of bpf_check() is still the same
and the condition can be removed.
Signed-off-by: Tobias Tefke <tobias.tefke@tutanota.com>
---
kernel/bpf/verifier.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 9e2bf834f13a..b022d0a85427 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5935,11 +5935,10 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr)
while (!pop_stack(env, NULL, NULL));
free_states(env);
- if (ret == 0)
+ if (ret == 0) {
sanitize_dead_code(env);
-
- if (ret == 0)
ret = check_max_stack_depth(env);
+ }
if (ret == 0)
/* program is valid, convert *(u32*)(ctx + off) accesses */
--
2.18.0
next reply other threads:[~2018-07-09 11:48 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-09 11:48 Tobias Tefke [this message]
2018-07-09 23:01 ` [PATCH] bpf: remove unnecessary condition in bpf_check() Alexei Starovoitov
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