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authorLinus Torvalds <torvalds@linux-foundation.org>2008-03-24 11:07:15 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-03-24 11:07:15 -0700
commit92896bd9fd75b1c993b92874d339a8088bb75560 (patch)
tree2bd8bc5a8c8ee10a4b1fd62804281d2b486067f0
parentd2532dd20a126020de407c1c2476a75b53fce7ac (diff)
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Don't 'printk()' while holding xtime lock for writing
The printk() can deadlock because it can wake up klogd(), and task enqueueing will try to read the time in order to set a hrtimer. Reported-by: Marcin Slusarz <marcin.slusarz@gmail.com> Debugged-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/time/timekeeping.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 671af612b768..a3fa587c350c 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -191,8 +191,12 @@ static void change_clocksource(void)
tick_clock_notify();
+ /*
+ * We're holding xtime lock and waking up klogd would deadlock
+ * us on enqueue. So no printing!
printk(KERN_INFO "Time: %s clocksource has been installed.\n",
clock->name);
+ */
}
#else
static inline void change_clocksource(void) { }