diff options
author | George Anzinger <george@mvista.com> | 2005-07-29 04:16:16 (GMT) |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-07-29 04:46:05 (GMT) |
commit | 78fa74a23b16bdb0d944272b696915c4e0bb3ee1 (patch) | |
tree | 5f0d83021afeb7adffce9b41557e1d2e3c8c08bd /kernel | |
parent | a2d76bd8fa29f9b6dbf3ee8f6bc7bdda21bc5ce8 (diff) | |
download | linux-78fa74a23b16bdb0d944272b696915c4e0bb3ee1.tar.xz |
[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 <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/posix-timers.c | 17 |
1 files changed, 3 insertions, 14 deletions
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c index 5b7b473..10b2ad7 100644 --- a/kernel/posix-timers.c +++ b/kernel/posix-timers.c @@ -896,21 +896,10 @@ static int adjust_abs_time(struct k_clock *clock, struct timespec *tp, 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(); } |