1 files changed, 17 insertions, 2 deletions

diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index c556ed9db13d..81f13958e751 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -46,7 +46,7 @@
 #include <asm/irq_regs.h>
 
 /* Whether we react on sysrq keys or just ignore them */
-static int __read_mostly sysrq_enabled = 1;
+static int __read_mostly sysrq_enabled = SYSRQ_DEFAULT_ENABLE;
 static bool __read_mostly sysrq_always_enabled;
 
 static bool sysrq_on(void)
@@ -571,6 +571,7 @@ struct sysrq_state {
         unsigned int alt_use;
         bool active;
         bool need_reinject;
+        bool reinjecting;
 };
 
 static void sysrq_reinject_alt_sysrq(struct work_struct *work)
@@ -581,6 +582,10 @@ static void sysrq_reinject_alt_sysrq(struct work_struct *work)
         unsigned int alt_code = sysrq->alt_use;
 
         if (sysrq->need_reinject) {
+                /* we do not want the assignment to be reordered */
+                sysrq->reinjecting = true;
+                mb();
+
                 /* Simulate press and release of Alt + SysRq */
                 input_inject_event(handle, EV_KEY, alt_code, 1);
                 input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1);
@@ -589,6 +594,9 @@ static void sysrq_reinject_alt_sysrq(struct work_struct *work)
                 input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0);
                 input_inject_event(handle, EV_KEY, alt_code, 0);
                 input_inject_event(handle, EV_SYN, SYN_REPORT, 1);
+
+                mb();
+                sysrq->reinjecting = false;
         }
 }
 
@@ -599,6 +607,13 @@ static bool sysrq_filter(struct input_handle *handle,
         bool was_active = sysrq->active;
         bool suppress;
 
+        /*
+         * Do not filter anything if we are in the process of re-injecting
+         * Alt+SysRq combination.
+         */
+        if (sysrq->reinjecting)
+                return false;
+
         switch (type) {
 
         case EV_SYN:
@@ -629,7 +644,7 @@ static bool sysrq_filter(struct input_handle *handle,
                                 sysrq->alt_use = sysrq->alt;
                                 /*
                                  * If nothing else will be pressed we'll need
-                                 * to * re-inject Alt-SysRq keysroke.
+                                 * to re-inject Alt-SysRq keysroke.
                                  */
                                 sysrq->need_reinject = true;
                         }