diff options
Diffstat (limited to 'trunk/2.6.18/30053_hrtimer-large-relative-timeouts-overflow.patch')
| -rw-r--r-- | trunk/2.6.18/30053_hrtimer-large-relative-timeouts-overflow.patch | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/trunk/2.6.18/30053_hrtimer-large-relative-timeouts-overflow.patch b/trunk/2.6.18/30053_hrtimer-large-relative-timeouts-overflow.patch new file mode 100644 index 0000000..57c2b94 --- /dev/null +++ b/trunk/2.6.18/30053_hrtimer-large-relative-timeouts-overflow.patch @@ -0,0 +1,45 @@ +From: Thomas Gleixner <tglx@linutronix.de> +Date: Fri, 7 Dec 2007 18:16:17 +0000 (+0100) +Subject: hrtimers: avoid overflow for large relative timeouts +X-Git-Tag: v2.6.24-rc5~49^2~2 +X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=62f0f61e6673e67151a7c8c0f9a09c7ea43fe2b5;hp=f194d132e4971111f85c18c96067acffb13cee6d + +hrtimers: avoid overflow for large relative timeouts + +Relative hrtimers with a large timeout value might end up as negative +timer values, when the current time is added in hrtimer_start(). + +This in turn is causing the clockevents_set_next() function to set an +huge timeout and sleep for quite a long time when we have a clock +source which is capable of long sleeps like HPET. With PIT this almost +goes unnoticed as the maximum delta is ~27ms. The non-hrt/nohz code +sorts this out in the next timer interrupt, so we never noticed that +problem which has been there since the first day of hrtimers. + +This bug became more apparent in 2.6.24 which activates HPET on more +hardware. + +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Signed-off-by: Ingo Molnar <mingo@elte.hu> +--- + +Adjusted to apply to Debian's 2.6.18 by dann frazier <dannf@debian.org> + +diff -urpN linux-source-2.6.18.orig/kernel/hrtimer.c linux-source-2.6.18/kernel/hrtimer.c +--- linux-source-2.6.18.orig/kernel/hrtimer.c 2006-09-19 21:42:06.000000000 -0600 ++++ linux-source-2.6.18/kernel/hrtimer.c 2007-12-16 18:43:03.000000000 -0700 +@@ -443,6 +443,14 @@ hrtimer_start(struct hrtimer *timer, kti + #ifdef CONFIG_TIME_LOW_RES + tim = ktime_add(tim, base->resolution); + #endif ++ /* ++ * Careful here: User space might have asked for a ++ * very long sleep, so the add above might result in a ++ * negative number, which enqueues the timer in front ++ * of the queue. ++ */ ++ if (tim.tv64 < 0) ++ tim.tv64 = KTIME_MAX; + } + timer->expires = tim; + |