| From | Andi Kleen <> | Subject | [PATCH] [63/275] fix jiffy calculations in calibrate_delay_direct to handle overflow | Date | Wed, 30 Mar 2011 14:04:59 -0700 (PDT) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Tim Deegan <Tim.Deegan@citrix.com>
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@citrix.com> Signed-off-by: Andi Kleen <ak@linux.intel.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> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- 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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