sh: fix xtime_lock deadlocking.

move update_process_times() out from under xtime_lock.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

diff --git a/arch/sh/kernel/time_32.c b/arch/sh/kernel/time_32.c
index 2bc04bfee73891045e92df6506287aa5ce1e102b..7281342c044d6dd24247ea33fa89060c687fbc88 100644 (file)
--- a/arch/sh/kernel/time_32.c
+++ b/arch/sh/kernel/time_32.c
@@ -120,10 +120,6 @@ static long last_rtc_update;
  */
 void handle_timer_tick(void)
 {
-       do_timer(1);
-#ifndef CONFIG_SMP
-       update_process_times(user_mode(get_irq_regs()));
-#endif
        if (current->pid)
                profile_tick(CPU_PROFILING);
 
@@ -132,6 +128,16 @@ void handle_timer_tick(void)
                sh_mv.mv_heartbeat();
 #endif
 
+       /*
+        * Here we are in the timer irq handler. We just have irqs locally
+        * disabled but we don't know if the timer_bh is running on the other
+        * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
+        * the irq version of write_lock because as just said we have irq
+        * locally disabled. -arca
+        */
+       write_seqlock(&xtime_lock);
+       do_timer(1);
+
        /*
         * If we have an externally synchronized Linux clock, then update
         * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
@@ -147,6 +153,11 @@ void handle_timer_tick(void)
                        /* do it again in 60s */
                        last_rtc_update = xtime.tv_sec - 600;
        }
+       write_sequnlock(&xtime_lock);
+
+#ifndef CONFIG_SMP
+       update_process_times(user_mode(get_irq_regs()));
+#endif
 }
 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 

diff --git a/arch/sh/kernel/time_64.c b/arch/sh/kernel/time_64.c
index f819ba38a6ce223e0a6352b8e68d636e260c76c0..898977ee2030d99ca792425f22e58464b9ee8a0d 100644 (file)
--- a/arch/sh/kernel/time_64.c
+++ b/arch/sh/kernel/time_64.c
@@ -229,15 +229,22 @@ static long last_rtc_update;
 static inline void do_timer_interrupt(void)
 {
        unsigned long long current_ctc;
+
+       if (current->pid)
+               profile_tick(CPU_PROFILING);
+
+       /*
+        * Here we are in the timer irq handler. We just have irqs locally
+        * disabled but we don't know if the timer_bh is running on the other
+        * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
+        * the irq version of write_lock because as just said we have irq
+        * locally disabled. -arca
+        */
+       write_lock(&xtime_lock);
        asm ("getcon cr62, %0" : "=r" (current_ctc));
        ctc_last_interrupt = (unsigned long) current_ctc;
 
        do_timer(1);
-#ifndef CONFIG_SMP
-       update_process_times(user_mode(get_irq_regs()));
-#endif
-       if (current->pid)
-               profile_tick(CPU_PROFILING);
 
 #ifdef CONFIG_HEARTBEAT
        if (sh_mv.mv_heartbeat != NULL)
@@ -259,6 +266,11 @@ static inline void do_timer_interrupt(void)
                        /* do it again in 60 s */
                        last_rtc_update = xtime.tv_sec - 600;
        }
+       write_unlock(&xtime_lock);
+
+#ifndef CONFIG_SMP
+       update_process_times(user_mode(get_irq_regs()));
+#endif
 }
 
 /*
@@ -275,16 +287,7 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id)
        timer_status &= ~0x100;
        ctrl_outw(timer_status, TMU0_TCR);
 
-       /*
-        * Here we are in the timer irq handler. We just have irqs locally
-        * disabled but we don't know if the timer_bh is running on the other
-        * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
-        * the irq version of write_lock because as just said we have irq
-        * locally disabled. -arca
-        */
-       write_lock(&xtime_lock);
        do_timer_interrupt();
-       write_unlock(&xtime_lock);
 
        return IRQ_HANDLED;
 }