2018-05-16 20:28:28

by Mathieu Malaterre

Subject: [PATCH] bpf: add __printf verification to bpf_verifier_vlog

__printf is useful to verify format and arguments. ‘bpf_verifier_vlog’
function is used twice in verifier.c in both cases the caller function
already uses the __printf gcc attribute.

Remove the following warning, triggered with W=1:

kernel/bpf/verifier.c:176:2: warning: function might be possible candidate for ‘gnu_printf’ format attribute [-Wsuggest-attribute=format]

Signed-off-by: Mathieu Malaterre <[email protected]>
---
include/linux/bpf_verifier.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 7e61c395fddf..ebf78f8ddfa1 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -197,8 +197,8 @@ struct bpf_verifier_env {
u32 subprog_cnt;
};

-void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt,
- va_list args);
+__printf(2, 0) void bpf_verifier_vlog(struct bpf_verifier_log *log,
+ const char *fmt, va_list args);
__printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env,
const char *fmt, ...);

--
2.11.0

2018-05-16 23:01:37

by Daniel Borkmann

Subject: Re: [PATCH] bpf: add __printf verification to bpf_verifier_vlog

On 05/16/2018 10:27 PM, Mathieu Malaterre wrote:
> __printf is useful to verify format and arguments. ‘bpf_verifier_vlog’
> function is used twice in verifier.c in both cases the caller function
> already uses the __printf gcc attribute.
>
> Remove the following warning, triggered with W=1:
>
> kernel/bpf/verifier.c:176:2: warning: function might be possible candidate for ‘gnu_printf’ format attribute [-Wsuggest-attribute=format]
>
> Signed-off-by: Mathieu Malaterre <[email protected]>

Looks good, applied to bpf-next, thanks Mathieu!