tree 5f0d83021afeb7adffce9b41557e1d2e3c8c08bd
parent a2d76bd8fa29f9b6dbf3ee8f6bc7bdda21bc5ce8
author George Anzinger <george@mvista.com> Fri, 29 Jul 2005 11:16:16 -0700
committer Linus Torvalds <[EMAIL PROTECTED]> Fri, 29 Jul 2005 11:46:05 -0700
[PATCH] posix timers: fix normalization problem
(We found this (after a customer complained) and it is in the kernel.org
kernel. Seems that for CLOCK_MONOTONIC absolute timers and clock_nanosleep
calls both the request time and wall_to_monotonic are subtracted prior to
the normalize resulting in an overflow in the existing normalize test.
This causes the result to be shifted ~4 seconds ahead instead of ~2 seconds
back in time.)
The normalize code in posix-timers.c fails when the tv_nsec member is ~1.2
seconds negative. This can happen on absolute timers (and
clock_nanosleeps) requested on CLOCK_MONOTONIC (both the request time and
wall_to_monotonic are subtracted resulting in the possibility of a number
close to -2 seconds.)
This fix uses the set_normalized_timespec() (which does not have an
overflow problem) to fix the problem and as a side effect makes the code
cleaner.
Signed-off-by: George Anzinger <george@mvista.com>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
kernel/posix-timers.c | 17 +++--------------
1 files changed, 3 insertions(+), 14 deletions(-)
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -896,21 +896,10 @@ static int adjust_abs_time(struct k_cloc
jiffies_64_f = get_jiffies_64();
}
/*
- * Take away now to get delta
+ * Take away now to get delta and normalize
*/
- oc.tv_sec -= now.tv_sec;
- oc.tv_nsec -= now.tv_nsec;
- /*
- * Normalize...
- */
- while ((oc.tv_nsec - NSEC_PER_SEC) >= 0) {
- oc.tv_nsec -= NSEC_PER_SEC;
- oc.tv_sec++;
- }
- while ((oc.tv_nsec) < 0) {
- oc.tv_nsec += NSEC_PER_SEC;
- oc.tv_sec--;
- }
+ set_normalized_timespec(&oc, oc.tv_sec - now.tv_sec,
+ oc.tv_nsec - now.tv_nsec);
}else{
jiffies_64_f = get_jiffies_64();
}
-
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