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authorLinus Torvalds <torvalds@linux-foundation.org>2019-08-19 16:17:59 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-08-19 16:17:59 -0700
commit287c55ed7df531c30f7a5093120339193dc7f166 (patch)
treea00ed23981296e618c07ccbb5ceb7e4e59d26b43 /kernel
parent06821504fd47a5e5b641aeeb638a0ae10a216ef8 (diff)
parent33da8e7c814f77310250bb54a9db36a44c5de784 (diff)
downloadlinux-287c55ed7df531c30f7a5093120339193dc7f166.tar.bz2
Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull kernel thread signal handling fix from Eric Biederman: "I overlooked the fact that kernel threads are created with all signals set to SIG_IGN, and accidentally caused a regression in cifs and drbd when replacing force_sig with send_sig. This is my fix for that regression. I add a new function allow_kernel_signal which allows kernel threads to receive signals sent from the kernel, but continues to ignore all signals sent from userspace. This ensures the user space interface for cifs and drbd remain the same. These kernel threads depend on blocking networking calls which block until something is received or a signal is pending. Making receiving of signals somewhat necessary for these kernel threads. Perhaps someday we can cleanup those interfaces and remove allow_kernel_signal. If not allow_kernel_signal is pretty trivial and clearly documents what is going on so I don't think we will mind carrying it" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: signal: Allow cifs and drbd to receive their terminating signals
Diffstat (limited to 'kernel')
-rw-r--r--kernel/signal.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index e667be6907d7..534fec266a33 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -90,6 +90,11 @@ static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
handler == SIG_DFL && !(force && sig_kernel_only(sig)))
return true;
+ /* Only allow kernel generated signals to this kthread */
+ if (unlikely((t->flags & PF_KTHREAD) &&
+ (handler == SIG_KTHREAD_KERNEL) && !force))
+ return true;
+
return sig_handler_ignored(handler, sig);
}