[PATCH] [63/275] fix jiffy calculations in calibrate_delay_direct to handle overflow
From: Andi Kleen
Date: Wed Mar 30 2011 - 17:59:23 EST
2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------
From: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
commit 70a062286b9dfcbd24d2e11601aecfead5cf709a upstream.
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@xxxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
[jbeulich@xxxxxxxxxx: !time_after() -> time_before_eq() as suggested by Jiri Slaby]
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Cc: Jiri Slaby <jslaby@xxxxxxx>
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
init/calibrate.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
Index: linux-2.6.35.y/init/calibrate.c
===================================================================
--- linux-2.6.35.y.orig/init/calibrate.c 2011-03-29 22:51:44.697579468 -0700
+++ linux-2.6.35.y/init/calibrate.c 2011-03-29 23:02:59.497313032 -0700
@@ -66,7 +66,7 @@
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 @@
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);
}
--
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