sysrq: Properly check for kernel threads
There's a real possibility of killing kernel threads that might
have issued use_mm(), so kthread's mm might become non-NULL.
This patch fixes the issue by checking for PF_KTHREAD (just as
get_task_mm()).
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index a1bcad7..8db9125 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -324,9 +324,12 @@
read_lock(&tasklist_lock);
for_each_process(p) {
- if (p->mm && !is_global_init(p))
- /* Not swapper, init nor kernel thread */
- force_sig(sig, p);
+ if (p->flags & PF_KTHREAD)
+ continue;
+ if (is_global_init(p))
+ continue;
+
+ force_sig(sig, p);
}
read_unlock(&tasklist_lock);
}