diff options
Diffstat (limited to 'debian/patches-rt/sched-completion-Fix-a-lockup-in-wait_for_completion.patch')
| -rw-r--r-- | debian/patches-rt/sched-completion-Fix-a-lockup-in-wait_for_completion.patch | 61 |
1 files changed, 0 insertions, 61 deletions
diff --git a/debian/patches-rt/sched-completion-Fix-a-lockup-in-wait_for_completion.patch b/debian/patches-rt/sched-completion-Fix-a-lockup-in-wait_for_completion.patch deleted file mode 100644 index 053dc7f67..000000000 --- a/debian/patches-rt/sched-completion-Fix-a-lockup-in-wait_for_completion.patch +++ /dev/null @@ -1,61 +0,0 @@ -From: Corey Minyard <cminyard@mvista.com> -Date: Thu, 9 May 2019 14:33:20 -0500 -Subject: [PATCH] sched/completion: Fix a lockup in wait_for_completion() -Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.2/older/patches-5.2.17-rt9.tar.xz - -Consider following race: - - T0 T1 T2 - wait_for_completion() - do_wait_for_common() - __prepare_to_swait() - schedule() - complete() - x->done++ (0 -> 1) - raw_spin_lock_irqsave() - swake_up_locked() wait_for_completion() - wake_up_process(T0) - list_del_init() - raw_spin_unlock_irqrestore() - raw_spin_lock_irq(&x->wait.lock) - raw_spin_lock_irq(&x->wait.lock) x->done != UINT_MAX, 1 -> 0 - raw_spin_unlock_irq(&x->wait.lock) - return 1 - while (!x->done && timeout), - continue loop, not enqueued - on &x->wait - -Basically, the problem is that the original wait queues used in -completions did not remove the item from the queue in the wakeup -function, but swake_up_locked() does. - -Fix it by adding the thread to the wait queue inside the do loop. -The design of swait detects if it is already in the list and doesn't -do the list add again. - -Cc: stable-rt@vger.kernel.org -Fixes: a04ff6b4ec4ee7e ("completion: Use simple wait queues") -Signed-off-by: Corey Minyard <cminyard@mvista.com> -Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> -[bigeasy: shorten commit message ] -Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> ---- - kernel/sched/completion.c | 2 +- - 1 file changed, 1 insertion(+), 1 deletion(-) - ---- a/kernel/sched/completion.c -+++ b/kernel/sched/completion.c -@@ -72,12 +72,12 @@ do_wait_for_common(struct completion *x, - if (!x->done) { - DECLARE_SWAITQUEUE(wait); - -- __prepare_to_swait(&x->wait, &wait); - do { - if (signal_pending_state(state, current)) { - timeout = -ERESTARTSYS; - break; - } -+ __prepare_to_swait(&x->wait, &wait); - __set_current_state(state); - raw_spin_unlock_irq(&x->wait.lock); - timeout = action(timeout); |