From ff60a5dc4fa584d47022d2533bc5c53b80096fb5 Mon Sep 17 00:00:00 2001 From: "akpm@osdl.org" Date: Wed, 1 Feb 2006 03:05:10 -0800 Subject: [PATCH] hrtimers: fix posix-timer requeue race From: Steven Rostedtrostedt@goodmis.org CPU0 expires a posix-timer and runs the callback function. The signal is queued. After releasing the posix-timer lock and before returning to hrtimer_run_queue CPU0 gets interrupted. CPU1 delivers the queued signal and rearms the timer. CPU0 comes back to hrtimer_run_queue and sets the timer state to expired. The next modification of the timer can result in an oops, because the state information is wrong. Keep track of state = RUNNING and check if the state has been in the return path of hrtimer_run_queue. In case the state has been changed, ignore a restart request and do not touch the state variable. Signed-off-by: Steven Rostedt Signed-off-by: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/hrtimer.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 089bfb1fa01a..c657f3d4924a 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -40,6 +40,7 @@ enum hrtimer_restart { enum hrtimer_state { HRTIMER_INACTIVE, /* Timer is inactive */ HRTIMER_EXPIRED, /* Timer is expired */ + HRTIMER_RUNNING, /* Timer is running the callback function */ HRTIMER_PENDING, /* Timer is pending */ }; -- cgit v1.2.2 From 7978672c4d9a1e6a6081de3a9d9ba5e5b24904a0 Mon Sep 17 00:00:00 2001 From: George Anzinger Date: Wed, 1 Feb 2006 03:05:11 -0800 Subject: [PATCH] hrtimers: cleanups and simplifications Clean up the interface to hrtimers by changing the init code to pass the mode as well as the clock. This allow the init code to select the correct base and eliminates extra timer re-init code in posix-timers. We also simplify the restart interface nanosleep use. Signed-off-by: George Anzinger Signed-off-by: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/hrtimer.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'include/linux/hrtimer.h') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index c657f3d4924a..6361544bb6ae 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -101,9 +101,8 @@ struct hrtimer_base { /* Exported timer functions: */ /* Initialize timers: */ -extern void hrtimer_init(struct hrtimer *timer, const clockid_t which_clock); -extern void hrtimer_rebase(struct hrtimer *timer, const clockid_t which_clock); - +extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, + enum hrtimer_mode mode); /* Basic timer operations: */ extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, -- cgit v1.2.2