The patch titled hrtimer: prevent migration for raising softirq has been removed from the -mm tree. Its filename was hrtimer-prevent-migration-for-raising-softirq.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: hrtimer: prevent migration for raising softirq From: Steven Rostedt <rostedt@xxxxxxxxxxx> Due to a possible deadlock, the waking of the softirq was pushed outside of the hrtimer base locks. See commit 0c96c5979a522c3323c30a078a70120e29b5bdbc Unfortunately this allows the task to migrate after setting up the softirq and raising it. Since softirqs run a queue that is per-cpu we may raise the softirq on the wrong CPU and this will keep the queued softirq task from running. To solve this issue, this patch disables preemption around the releasing of the hrtimer lock and raising of the softirq. Signed-off-by: Steven Rostedt <srostedt@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: <stable@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/hrtimer.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff -puN kernel/hrtimer.c~hrtimer-prevent-migration-for-raising-softirq kernel/hrtimer.c --- a/kernel/hrtimer.c~hrtimer-prevent-migration-for-raising-softirq +++ a/kernel/hrtimer.c @@ -1003,10 +1003,18 @@ hrtimer_start(struct hrtimer *timer, kti */ raise = timer->state == HRTIMER_STATE_PENDING; + /* + * We use preempt_disable to prevent this task from migrating after + * setting up the softirq and raising it. Otherwise, if me migrate + * we will raise the softirq on the wrong CPU. + */ + preempt_disable(); + unlock_hrtimer_base(timer, &flags); if (raise) hrtimer_raise_softirq(); + preempt_enable(); return ret; } _ Patches currently in -mm which might be from rostedt@xxxxxxxxxxx are origin.patch linux-next.patch ftrace-disable-function-tracing-bringing-up-new-cpu.patch split-the-typecheck-macros-out-of-include-linux-kernelh.patch locking-add-typecheck-on-irqsave-and-friends-for-correct-flags.patch locking-add-typecheck-on-irqsave-and-friends-for-correct-flags-fix.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html