-stable review patch. If anyone has any objections, please let us know. ------------------
The clock_was_set() call in seconds_overflow() which happens only when leap seconds are inserted / deleted is wrong in two aspects: 1. it results in a call to on_each_cpu() with interrupts disabled 2. it is potential deadlock source vs. call_lock in smp_call_function() The only possible side effect of the removal might be, that an absolute CLOCK_REALTIME timer fires 1 second too late, in the rare case of leap second deletion and an absolute CLOCK_REALTIME timer which expires in the affected time frame. It will never fire too early. This was probably observed by the reporter of a June 30th -> July 1st hang: http://lkml.org/lkml/2007/7/3/ A similar problem was observed by Dave Jones, who provided a screen shot with a lockdep back trace, which allowed to analyse the problem. Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]> Cc: john stultz <[EMAIL PROTECTED]> Cc: Dave Jones <[EMAIL PROTECTED]> Cc: Ingo Molnar <[EMAIL PROTECTED]> Cc: Vincent Fortier <[EMAIL PROTECTED]> Signed-off-by: Chris Wright <[EMAIL PROTECTED]> Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]> --- kernel/time/ntp.c | 2 -- 1 file changed, 2 deletions(-) --- linux-2.6.21.6.orig/kernel/time/ntp.c +++ linux-2.6.21.6/kernel/time/ntp.c @@ -120,7 +120,6 @@ void second_overflow(void) */ time_interpolator_update(-NSEC_PER_SEC); time_state = TIME_OOP; - clock_was_set(); printk(KERN_NOTICE "Clock: inserting leap second " "23:59:60 UTC\n"); } @@ -135,7 +134,6 @@ void second_overflow(void) */ time_interpolator_update(NSEC_PER_SEC); time_state = TIME_WAIT; - clock_was_set(); printk(KERN_NOTICE "Clock: deleting leap second " "23:59:59 UTC\n"); } -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
