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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 /include
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 'include')
-rw-r--r--include/linux/time.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/time.h b/include/linux/time.h
index d9cdba54b78..bf0e785e2e0 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -101,6 +101,7 @@ extern long do_utimes(int dfd, char __user *filename, struct timeval *times);
struct itimerval;
extern int do_setitimer(int which, struct itimerval *value,
struct itimerval *ovalue);
+extern unsigned int alarm_setitimer(unsigned int seconds);
extern int do_getitimer(int which, struct itimerval *value);
extern void getnstimeofday(struct timespec *tv);