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 3.18-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-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From ac25385089f673560867eb5179228a44ade0cfc1 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov <oleg@xxxxxxxxxx> 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@xxxxxxxxxx> 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@xxxxxxxxxx Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Tested-by: Kyle Huey <me@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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@xxxxxxxxxx are queue-3.18/kernel-signal.c-remove-the-no-longer-needed-signal_unkillable-check-in-complete_signal.patch queue-3.18/kernel-signal.c-protect-the-signal_unkillable-tasks-from-sig_kernel_only-signals.patch queue-3.18/kernel-acct.c-fix-the-acct-needcheck-check-in-check_free_space.patch queue-3.18/kernel-signal.c-protect-the-traced-signal_unkillable-tasks-from-sigkill.patch