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authorThomas Gleixner <tglx@linutronix.de>2006-03-25 03:06:33 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-25 08:22:48 -0800
commitc08b8a49100715b20e6f7c997e992428b5e06078 (patch)
tree014758fb05908a3d49eeadc77f16dfa7585b12ac /kernel/timer.c
parent185ae6d7a32721e9062030a9f2d24ed714fa45df (diff)
[PATCH] sys_alarm() unsigned signed conversion fixup
alarm() calls the kernel with an unsigend int timeout in seconds. The value is stored in the tv_sec field of a struct timeval to setup the itimer. The tv_sec field of struct timeval is of type long, which causes the tv_sec value to be negative on 32 bit machines if seconds > INT_MAX. Before the hrtimer merge (pre 2.6.16) such a negative value was converted to the maximum jiffies timeout by the timeval_to_jiffies conversion. It's not clear whether this was intended or just happened to be done by the timeval_to_jiffies code. hrtimers expect a timeval in canonical form and treat a negative timeout as already expired. This breaks the legitimate usage of alarm() with a timeout value > INT_MAX seconds. For 32 bit machines it is therefor necessary to limit the internal seconds value to avoid API breakage. Instead of doing this in all implementations of sys_alarm the duplicated sys_alarm code is moved into a common function in itimer.c Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/timer.c')
-rw-r--r--kernel/timer.c14
1 files changed, 1 insertions, 13 deletions
diff --git a/kernel/timer.c b/kernel/timer.c
index 17d956cebcb..13fa72cac7d 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -956,19 +956,7 @@ void do_timer(struct pt_regs *regs)
*/
asmlinkage unsigned long sys_alarm(unsigned int seconds)
{
- struct itimerval it_new, it_old;
- unsigned int oldalarm;
-
- it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
- it_new.it_value.tv_sec = seconds;
- it_new.it_value.tv_usec = 0;
- do_setitimer(ITIMER_REAL, &it_new, &it_old);
- oldalarm = it_old.it_value.tv_sec;
- /* ehhh.. We can't return 0 if we have an alarm pending.. */
- /* And we'd better return too much than too little anyway */
- if ((!oldalarm && it_old.it_value.tv_usec) || it_old.it_value.tv_usec >= 500000)
- oldalarm++;
- return oldalarm;
+ return alarm_setitimer(seconds);
}
#endif