Commit 70a06228 authored Feb 10, 2011 by Tim Deegan Committed by Linus Torvalds Feb 10, 2011

fix jiffy calculations in calibrate_delay_direct to handle overflow



Fixes a hang when booting as dom0 under Xen, when jiffies can be
quite large by the time the kernel init gets this far.

Signed-off-by: Tim Deegan <Tim.Deegan@citrix.com>
[jbeulich@novell.com: !time_after() -> time_before_eq() as suggested by Jiri Slaby]
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 6148a47a

init/calibrate.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -66,7 +66,7 @@ static unsigned long __cpuinit calibrate_delay_direct(void)
		pre_start = 0;
		read_current_timer(&start);
		start_jiffies = jiffies;
		while (jiffies <= (start_jiffies + 1)) {
		while (time_before_eq(jiffies, start_jiffies + 1)) {
		pre_start = start;
		read_current_timer(&start);
		}
		@@ -74,8 +74,8 @@ static unsigned long __cpuinit calibrate_delay_direct(void)

		pre_end = 0;
		end = post_start;
		while (jiffies <=
		(start_jiffies + 1 + DELAY_CALIBRATION_TICKS)) {
		while (time_before_eq(jiffies, start_jiffies + 1 +
		DELAY_CALIBRATION_TICKS)) {
		pre_end = end;
		read_current_timer(&end);
		}