Patch "signal: remove warning about using SI_TKILL in rt_[tg]sigqueueinfo" has been added to the 3.14-stable tree

This is a note to let you know that I've just added the patch titled

signal: remove warning about using SI_TKILL in rt_[tg]sigqueueinfo

to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
signal-remove-warning-about-using-si_tkill-in-rt_sigqueueinfo.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Vladimir Davydov <[email protected]>
Date: Thu, 16 Apr 2015 12:47:35 -0700
Subject: signal: remove warning about using SI_TKILL in rt_[tg]sigqueueinfo

From: Vladimir Davydov <[email protected]>

commit 69828dce7af2cb6d08ef5a03de687d422fb7ec1f upstream.

Sending SI_TKILL from rt_[tg]sigqueueinfo was deprecated, so now we issue a warning on the first attempt of doing it. We use WARN_ON_ONCE, which is not informative and, what is worse, taints the kernel, making the trinity syscall fuzzer complain false-positively from time to time.

It does not look like we need this warning at all, because the behaviour changed quite a long time ago (2.6.39), and if an application relies on the old API, it gets EPERM anyway and can issue a warning by itself.

So let us zap the warning in kernel.

---
 kernel/signal.c |   14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

@@ -3004,11 +3004,9 @@ static int do_rt_sigqueueinfo(pid_t pid,
 	 * Nor can they impersonate a kill()/tgkill(), which adds source info.
 	 */
 	if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
-	    (task_pid_vnr(current) != pid)) {
-		/* We used to allow any < 0 si_code */
-		WARN_ON_ONCE(info->si_code < 0);
+	    (task_pid_vnr(current) != pid))
 		return -EPERM;
-	}
+
 	info->si_signo = sig;
 
 	/* POSIX.1b doesn't mention process groups.  */

@@ -3053,12 +3051,10 @@ static int do_rt_tgsigqueueinfo(pid_t tg
 	/* Not even root can pretend to send signals from the kernel.
 	 * Nor can they impersonate a kill()/tgkill(), which adds source info.
 	 */
-	if (((info->si_code >= 0 || info->si_code == SI_TKILL)) &&
-	    (task_pid_vnr(current) != pid)) {
-		/* We used to allow any < 0 si_code */
-		WARN_ON_ONCE(info->si_code < 0);
+	if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
+	    (task_pid_vnr(current) != pid))
 		return -EPERM;
-	}
+
 	info->si_signo = sig;
 
 	return do_send_specific(tgid, pid, sig, info);

Patches currently in stable-queue which might be from [email protected] are

queue-3.14/signal-remove-warning-about-using-si_tkill-in-rt_sigqueueinfo.patch