Patch "kernel/signal.c: protect the SIGNAL_UNKILLABLE tasks from !sig_kernel_only() signals" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

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

    kernel/signal.c: protect the SIGNAL_UNKILLABLE tasks from !sig_kernel_only() signals

to the 4.9-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:
     kernel-signal.c-protect-the-signal_unkillable-tasks-from-sig_kernel_only-signals.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From ac25385089f673560867eb5179228a44ade0cfc1 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Fri, 17 Nov 2017 15:30:04 -0800
Subject: kernel/signal.c: protect the SIGNAL_UNKILLABLE tasks from !sig_kernel_only() signals

From: Oleg Nesterov <oleg@redhat.com>

commit ac25385089f673560867eb5179228a44ade0cfc1 upstream.

Change sig_task_ignored() to drop the SIG_DFL && !sig_kernel_only()
signals even if force == T.  This simplifies the next change and this
matches the same check in get_signal() which will drop these signals
anyway.

Link: http://lkml.kernel.org/r/20171103184227.GC21036@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Kyle Huey <me@kylehuey.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/signal.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -72,7 +72,7 @@ static int sig_task_ignored(struct task_
 	handler = sig_handler(t, sig);
 
 	if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
-			handler == SIG_DFL && !force)
+	    handler == SIG_DFL && !(force && sig_kernel_only(sig)))
 		return 1;
 
 	return sig_handler_ignored(handler, sig);


Patches currently in stable-queue which might be from oleg@redhat.com are

queue-4.9/kernel-signal.c-remove-the-no-longer-needed-signal_unkillable-check-in-complete_signal.patch
queue-4.9/kernel-signal.c-protect-the-signal_unkillable-tasks-from-sig_kernel_only-signals.patch
queue-4.9/kernel-acct.c-fix-the-acct-needcheck-check-in-check_free_space.patch
queue-4.9/kernel-signal.c-protect-the-traced-signal_unkillable-tasks-from-sigkill.patch