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authorAnton Vorontsov <anton.vorontsov@linaro.org>2012-02-07 10:49:39 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-02-09 09:03:29 -0800
commite502babe0a85226f2417b60a8710cf8192879180 (patch)
tree6964ef225b6eded57757425c6faf3c59d1d0c21e /drivers/tty/sysrq.c
parent6f56d0f43656deb98c6366a133a75b5a7cf73a26 (diff)
downloadlinux-e502babe0a85226f2417b60a8710cf8192879180.tar.gz
sysrq: Fix possible race with exiting task
sysrq should grab the tasklist lock, otherwise calling force_sig() is
not safe, as it might race with exiting task, which ->sighand might be
set to NULL already.

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>
Diffstat (limited to 'drivers/tty/sysrq.c')
-rw-r--r--drivers/tty/sysrq.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 7867b7c4538e..a1bcad7ef739 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -322,11 +322,13 @@ static void send_sig_all(int sig)
 {
 	struct task_struct *p;
 
+	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);
 	}
+	read_unlock(&tasklist_lock);
 }
 
 static void sysrq_handle_term(int key)