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authorJiri Bohac <jbohac@suse.cz>2014-04-18 17:23:11 +0200
committerThomas Gleixner <tglx@linutronix.de>2014-04-30 13:46:17 +0200
commit98a01e779f3c66b0b11cd7e64d531c0e41c95762 (patch)
tree318f0b56031e4ee8789002f465ccaa30ffedc249 /kernel
parent012a45e3f4af68e86d85cce060c6c2fed56498b2 (diff)
downloadlinux-98a01e779f3c66b0b11cd7e64d531c0e41c95762.tar.gz
linux-98a01e779f3c66b0b11cd7e64d531c0e41c95762.tar.xz
timer: Prevent overflow in apply_slack
On architectures with sizeof(int) < sizeof (long), the computation of mask inside apply_slack() can be undefined if the computed bit is > 32. E.g. with: expires = 0xffffe6f5 and slack = 25, we get: expires_limit = 0x20000000e bit = 33 mask = (1 << 33) - 1 /* undefined */ On x86, mask becomes 1 and and the slack is not applied properly. On s390, mask is -1, expires is set to 0 and the timer fires immediately. Use 1UL << bit to solve that issue. Suggested-by: Deborah Townsend <dstownse@us.ibm.com> Signed-off-by: Jiri Bohac <jbohac@suse.cz> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20140418152310.GA13654@midget.suse.cz Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/timer.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/timer.c b/kernel/timer.c
index 87bd529..3bb01a3 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -838,7 +838,7 @@ unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
bit = find_last_bit(&mask, BITS_PER_LONG);
- mask = (1 << bit) - 1;
+ mask = (1UL << bit) - 1;
expires_limit = expires_limit & ~(mask);