From eaab2a6373909962fb66f24cd1a2de5063dd6c0e Mon Sep 17 00:00:00 2001 From: Joakim Hernberg Date: Thu, 30 Jun 2016 21:39:22 +0200 Subject: bump to 4.4.12_rt19-1 --- ...for-completion-simple-wait-code_Nvidia-RT.patch | 59 ---------------------- 1 file changed, 59 deletions(-) delete mode 100644 fix-race-in-PRT-wait-for-completion-simple-wait-code_Nvidia-RT.patch (limited to 'fix-race-in-PRT-wait-for-completion-simple-wait-code_Nvidia-RT.patch') diff --git a/fix-race-in-PRT-wait-for-completion-simple-wait-code_Nvidia-RT.patch b/fix-race-in-PRT-wait-for-completion-simple-wait-code_Nvidia-RT.patch deleted file mode 100644 index 29a172b..0000000 --- a/fix-race-in-PRT-wait-for-completion-simple-wait-code_Nvidia-RT.patch +++ /dev/null @@ -1,59 +0,0 @@ --NOTE: this patch is a rebase of John Blackwood's patch. On his kernel, he must be using --an older simple wait patch - as his applies to kernel/sched/core.c, while the simple wait --completion code lives in kernel/sched/completion.c ... I have ported this to test with --nvidia, as i would like to see if it fixes the semaphore issues i have seen. - --I've kept the original patch comment in tact; - -I'm not 100% sure that the patch below will fix your problem, but we -saw something that sounds pretty familiar to your issue involving the -nvidia driver and the preempt-rt patch. The nvidia driver uses the -completion support to create their own driver's notion of an internally -used semaphore. - -Fix a race in the PRT wait for completion simple wait code. - -A wait_for_completion() waiter task can be awoken by a task calling -complete(), but fail to consume the 'done' completion resource if it -looses a race with another task calling wait_for_completion() just as -it is waking up. - -In this case, the awoken task will call schedule_timeout() again -without being in the simple wait queue. - -So if the awoken task is unable to claim the 'done' completion resource, -check to see if it needs to be re-inserted into the wait list before -waiting again in schedule_timeout(). - -Fix-by: John Blackwood - ---- linux-3.14/kernel/sched/completion.c 2014-05-22 14:01:03.879734869 -0400 -+++ linux-3.14/kernel/sched/completion.c 2014-05-22 14:13:59.181688658 -0400 -@@ -61,11 +61,19 @@ - do_wait_for_common(struct completion *x, - long (*action)(long), long timeout, int state) - { -+ int again = 0; -+ - if (!x->done) { - DEFINE_SWAITER(wait); - - swait_prepare_locked(&x->wait, &wait); - do { -+ /* Check to see if we lost race for 'done' and are -+ * no longer in the wait list. -+ */ -+ if (unlikely(again) && list_empty(&wait.node)) -+ swait_prepare_locked(&x->wait, &wait); -+ - if (signal_pending_state(state, current)) { - timeout = -ERESTARTSYS; - break; -@@ -74,6 +82,7 @@ - raw_spin_unlock_irq(&x->wait.lock); - timeout = action(timeout); - raw_spin_lock_irq(&x->wait.lock); -+ again = 1; - } while (!x->done && timeout); - swait_finish_locked(&x->wait, &wait); - if (!x->done) -- cgit v1.2.3