time: Revert to calling clock_was_set_delayed() while in irq context

johnstultz-work · Ingo Molnar · commit cab5e127eef0 · 2014-03-28T08:07:07.000+01:00
In commit 47a1b79 ("tick/timekeeping: Call update_wall_time outside the jiffies lock"), we moved to calling clock_was_set() due to the fact that we were no longer holding the timekeeping or jiffies lock. However, there is still the problem that clock_was_set() triggers an IPI, which cannot be done from the timer's hard irq context, and will generate WARN_ON warnings. Apparently in my earlier testing, I'm guessing I didn't bump the dmesg log level, so I somehow missed the WARN_ONs. Thus we need to revert back to calling clock_was_set_delayed(). Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1395963049-11923-1-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
@@ -1435,7 +1435,8 @@ void update_wall_time(void)
 out:
 	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
 	if (clock_set)
-		clock_was_set();
+		/* Have to call _delayed version, since in irq context*/
+		clock_was_set_delayed();
 }
 
 /**

Original file line number	Diff line number	Diff line change
`@@ -1435,7 +1435,8 @@ void update_wall_time(void)`
`1435`	`1435`	`out:`
`1436`	`1436`	`raw_spin_unlock_irqrestore(&timekeeper_lock, flags);`
`1437`	`1437`	`if (clock_set)`
`1438`		`- clock_was_set();`
	`1438`	`+ /* Have to call _delayed version, since in irq context*/`
	`1439`	`+ clock_was_set_delayed();`
`1439`	`1440`	`}`
`1440`	`1441`
`1441`	`1442`	`/**`