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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)
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 671af612b76..a3fa587c350 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) { }