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authorTim Deegan <Tim.Deegan@citrix.com>2011-02-10 03:50:41 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2011-02-10 14:00:09 -0500
commit70a062286b9dfcbd24d2e11601aecfead5cf709a (patch)
tree126a1e3f9561a3cb4159714c96db1ddd4171756d /init/calibrate.c
parent6148a47ac3872092d4bc4888838bec6dff16654d (diff)
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>
Diffstat (limited to 'init/calibrate.c')
-rw-r--r--init/calibrate.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/init/calibrate.c b/init/calibrate.c
index 6eb48e53d61c..24fe022c55f9 100644
--- a/init/calibrate.c
+++ b/init/calibrate.c
@@ -66,7 +66,7 @@ static unsigned long __cpuinit calibrate_delay_direct(void)
66 pre_start = 0; 66 pre_start = 0;
67 read_current_timer(&start); 67 read_current_timer(&start);
68 start_jiffies = jiffies; 68 start_jiffies = jiffies;
69 while (jiffies <= (start_jiffies + 1)) { 69 while (time_before_eq(jiffies, start_jiffies + 1)) {
70 pre_start = start; 70 pre_start = start;
71 read_current_timer(&start); 71 read_current_timer(&start);
72 } 72 }
@@ -74,8 +74,8 @@ static unsigned long __cpuinit calibrate_delay_direct(void)
74 74
75 pre_end = 0; 75 pre_end = 0;
76 end = post_start; 76 end = post_start;
77 while (jiffies <= 77 while (time_before_eq(jiffies, start_jiffies + 1 +
78 (start_jiffies + 1 + DELAY_CALIBRATION_TICKS)) { 78 DELAY_CALIBRATION_TICKS)) {
79 pre_end = end; 79 pre_end = end;
80 read_current_timer(&end); 80 read_current_timer(&end);
81 } 81 }