From: Steven Rostedt <rostedt@goodmis.org>
To: kernel test robot <lkp@intel.com>
Cc: kbuild-all@lists.01.org, linux-kernel@vger.kernel.org
Subject: Re: kernel/trace/trace.c:3634:2: warning: function might be possible candidate for 'gnu_printf' format attribute
Date: Fri, 4 Jun 2021 16:48:38 -0400 [thread overview]
Message-ID: <20210604164838.2da06df3@oasis.local.home> (raw)
In-Reply-To: <202106041958.XB0yCLBn-lkp@intel.com>
On Fri, 4 Jun 2021 19:12:03 +0800
kernel test robot <lkp@intel.com> wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head: f88cd3fb9df228e5ce4e13ec3dbad671ddb2146e
> commit: 9a6944fee68e25084130386c608c5ac8db487581 tracing: Add a verifier to check string pointers for trace events
> date: 3 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=9a6944fee68e25084130386c608c5ac8db487581
> git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> git fetch --no-tags linus master
> git checkout 9a6944fee68e25084130386c608c5ac8db487581
> # 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@intel.com>
>
> All warnings (new ones prefixed by >>):
>
> kernel/trace/trace.c: In function 'test_can_verify_check':
> >> kernel/trace/trace.c:3634:2: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
> vsnprintf(buf, 16, "%d", ap);
> ^~~~~~~~~
"test_can_verify_check" is not a generic function that needs a printf
format check. This is a bogus warning. Please remove it as being an issue.
-- Steve
> kernel/trace/trace.c: In function 'trace_check_vprintf':
> kernel/trace/trace.c:3717:3: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
> trace_seq_vprintf(&iter->seq, iter->fmt, ap);
> ^~~~~~~~~~~~~~~~~
> kernel/trace/trace.c:3756:3: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
> trace_seq_vprintf(&iter->seq, p, ap);
> ^~~~~~~~~~~~~~~~~
>
>
> vim +/gnu_printf +3634 kernel/trace/trace.c
>
> 3617
> 3618 static int test_can_verify_check(const char *fmt, ...)
> 3619 {
> 3620 char buf[16];
> 3621 va_list ap;
> 3622 int ret;
> 3623
> 3624 /*
> 3625 * The verifier is dependent on vsnprintf() modifies the va_list
> 3626 * passed to it, where it is sent as a reference. Some architectures
> 3627 * (like x86_32) passes it by value, which means that vsnprintf()
> 3628 * does not modify the va_list passed to it, and the verifier
> 3629 * would then need to be able to understand all the values that
> 3630 * vsnprintf can use. If it is passed by value, then the verifier
> 3631 * is disabled.
> 3632 */
> 3633 va_start(ap, fmt);
> > 3634 vsnprintf(buf, 16, "%d", ap);
> 3635 ret = va_arg(ap, int);
> 3636 va_end(ap);
> 3637
> 3638 return ret;
> 3639 }
> 3640
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
WARNING: multiple messages have this Message-ID (diff)
From: Steven Rostedt <rostedt@goodmis.org>
To: kbuild-all@lists.01.org
Subject: Re: kernel/trace/trace.c:3634:2: warning: function might be possible candidate for 'gnu_printf' format attribute
Date: Fri, 04 Jun 2021 16:48:38 -0400 [thread overview]
Message-ID: <20210604164838.2da06df3@oasis.local.home> (raw)
In-Reply-To: <202106041958.XB0yCLBn-lkp@intel.com>
[-- Attachment #1: Type: text/plain, Size: 3096 bytes --]
On Fri, 4 Jun 2021 19:12:03 +0800
kernel test robot <lkp@intel.com> wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head: f88cd3fb9df228e5ce4e13ec3dbad671ddb2146e
> commit: 9a6944fee68e25084130386c608c5ac8db487581 tracing: Add a verifier to check string pointers for trace events
> date: 3 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=9a6944fee68e25084130386c608c5ac8db487581
> git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> git fetch --no-tags linus master
> git checkout 9a6944fee68e25084130386c608c5ac8db487581
> # 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@intel.com>
>
> All warnings (new ones prefixed by >>):
>
> kernel/trace/trace.c: In function 'test_can_verify_check':
> >> kernel/trace/trace.c:3634:2: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
> vsnprintf(buf, 16, "%d", ap);
> ^~~~~~~~~
"test_can_verify_check" is not a generic function that needs a printf
format check. This is a bogus warning. Please remove it as being an issue.
-- Steve
> kernel/trace/trace.c: In function 'trace_check_vprintf':
> kernel/trace/trace.c:3717:3: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
> trace_seq_vprintf(&iter->seq, iter->fmt, ap);
> ^~~~~~~~~~~~~~~~~
> kernel/trace/trace.c:3756:3: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
> trace_seq_vprintf(&iter->seq, p, ap);
> ^~~~~~~~~~~~~~~~~
>
>
> vim +/gnu_printf +3634 kernel/trace/trace.c
>
> 3617
> 3618 static int test_can_verify_check(const char *fmt, ...)
> 3619 {
> 3620 char buf[16];
> 3621 va_list ap;
> 3622 int ret;
> 3623
> 3624 /*
> 3625 * The verifier is dependent on vsnprintf() modifies the va_list
> 3626 * passed to it, where it is sent as a reference. Some architectures
> 3627 * (like x86_32) passes it by value, which means that vsnprintf()
> 3628 * does not modify the va_list passed to it, and the verifier
> 3629 * would then need to be able to understand all the values that
> 3630 * vsnprintf can use. If it is passed by value, then the verifier
> 3631 * is disabled.
> 3632 */
> 3633 va_start(ap, fmt);
> > 3634 vsnprintf(buf, 16, "%d", ap);
> 3635 ret = va_arg(ap, int);
> 3636 va_end(ap);
> 3637
> 3638 return ret;
> 3639 }
> 3640
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
next prev parent reply other threads:[~2021-06-04 20:48 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-04 11:12 kernel/trace/trace.c:3634:2: warning: function might be possible candidate for 'gnu_printf' format attribute kernel test robot
2021-06-04 11:12 ` kernel test robot
2021-06-04 20:48 ` Steven Rostedt [this message]
2021-06-04 20:48 ` Steven Rostedt
2021-06-07 5:49 ` [kbuild-all] " Rong Chen
2021-06-07 5:49 ` Rong Chen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210604164838.2da06df3@oasis.local.home \
--to=rostedt@goodmis.org \
--cc=kbuild-all@lists.01.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lkp@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.