kernel/bpf/btf.c:5346:22: warning: function might be possible candidate for 'gnu_printf' format attribute

From: kernel test robot
Date: Fri Jun 04 2021 - 04:23:22 EST


Hi Alan,

FYI, the error/warning still remains.

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: f88cd3fb9df228e5ce4e13ec3dbad671ddb2146e
commit: 31d0bc81637d8d974a6dad9827b765b4b70c89d7 bpf: Move to generic BTF show support, apply it to seq files/strings
date: 8 months ago
config: x86_64-rhel (attached as .config)
compiler: gcc-6 (Ubuntu 6.4.0-17ubuntu1) 6.4.0 20180424
reproduce (this is a W=1 build):
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=31d0bc81637d8d974a6dad9827b765b4b70c89d7
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 31d0bc81637d8d974a6dad9827b765b4b70c89d7
# save the attached .config to linux build tree
make W=1 ARCH=x86_64

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

kernel/bpf/btf.c: In function 'btf_seq_show':
>> kernel/bpf/btf.c:5346:22: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
seq_vprintf((struct seq_file *)show->target, fmt, args);
^~~~~~~~
kernel/bpf/btf.c: In function 'btf_snprintf_show':
kernel/bpf/btf.c:5383:2: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
^~~


vim +/gnu_printf +5346 kernel/bpf/btf.c

5342
5343 static void btf_seq_show(struct btf_show *show, const char *fmt,
5344 va_list args)
5345 {
> 5346 seq_vprintf((struct seq_file *)show->target, fmt, args);
5347 }
5348

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