From: Greg Kroah-Hartman Date: Sat, 13 Apr 2024 05:43:43 +0000 (+0200) Subject: drop queue-4.19/timers-move-clearing-of-base-timer_running-under-base-lock.patch X-Git-Tag: v4.19.312~8 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2fe49e80fad6456c8fc892509f8acdcd477db594;p=thirdparty%2Fkernel%2Fstable-queue.git drop queue-4.19/timers-move-clearing-of-base-timer_running-under-base-lock.patch --- diff --git a/queue-4.19/series b/queue-4.19/series index a9a0e826d27..c5137450466 100644 --- a/queue-4.19/series +++ b/queue-4.19/series @@ -104,7 +104,6 @@ usb-dwc2-gadget-lpm-flow-fix.patch usb-udc-remove-warning-when-queue-disabled-ep.patch scsi-qla2xxx-fix-command-flush-on-cable-pull.patch x86-cpu-enable-stibp-on-amd-if-automatic-ibrs-is-enabled.patch -timers-move-clearing-of-base-timer_running-under-base-lock.patch scsi-lpfc-correct-size-for-wqe-for-memset.patch usb-core-fix-deadlock-in-usb_deauthorize_interface.patch nfc-nci-fix-uninit-value-in-nci_dev_up-and-nci_ntf_p.patch diff --git a/queue-4.19/timers-move-clearing-of-base-timer_running-under-base-lock.patch b/queue-4.19/timers-move-clearing-of-base-timer_running-under-base-lock.patch deleted file mode 100644 index 7af8f7b363d..00000000000 --- a/queue-4.19/timers-move-clearing-of-base-timer_running-under-base-lock.patch +++ /dev/null @@ -1,84 +0,0 @@ -From bb7262b295472eb6858b5c49893954794027cd84 Mon Sep 17 00:00:00 2001 -From: Thomas Gleixner -Date: Sun, 6 Dec 2020 22:40:07 +0100 -Subject: timers: Move clearing of base::timer_running under base:: Lock - -From: Thomas Gleixner - -commit bb7262b295472eb6858b5c49893954794027cd84 upstream. - -syzbot reported KCSAN data races vs. timer_base::timer_running being set to -NULL without holding base::lock in expire_timers(). - -This looks innocent and most reads are clearly not problematic, but -Frederic identified an issue which is: - - int data = 0; - - void timer_func(struct timer_list *t) - { - data = 1; - } - - CPU 0 CPU 1 - ------------------------------ -------------------------- - base = lock_timer_base(timer, &flags); raw_spin_unlock(&base->lock); - if (base->running_timer != timer) call_timer_fn(timer, fn, baseclk); - ret = detach_if_pending(timer, base, true); base->running_timer = NULL; - raw_spin_unlock_irqrestore(&base->lock, flags); raw_spin_lock(&base->lock); - - x = data; - -If the timer has previously executed on CPU 1 and then CPU 0 can observe -base->running_timer == NULL and returns, assuming the timer has completed, -but it's not guaranteed on all architectures. The comment for -del_timer_sync() makes that guarantee. Moving the assignment under -base->lock prevents this. - -For non-RT kernel it's performance wise completely irrelevant whether the -store happens before or after taking the lock. For an RT kernel moving the -store under the lock requires an extra unlock/lock pair in the case that -there is a waiter for the timer, but that's not the end of the world. - -Reported-by: syzbot+aa7c2385d46c5eba0b89@syzkaller.appspotmail.com -Reported-by: syzbot+abea4558531bae1ba9fe@syzkaller.appspotmail.com -Fixes: 030dcdd197d7 ("timers: Prepare support for PREEMPT_RT") -Signed-off-by: Thomas Gleixner -Tested-by: Sebastian Andrzej Siewior -Link: https://lore.kernel.org/r/87lfea7gw8.fsf@nanos.tec.linutronix.de -Cc: stable@vger.kernel.org -Signed-off-by: Greg Kroah-Hartman ---- - kernel/time/timer.c | 6 ++++-- - 1 file changed, 4 insertions(+), 2 deletions(-) - ---- a/kernel/time/timer.c -+++ b/kernel/time/timer.c -@@ -1304,8 +1304,10 @@ static inline void timer_base_unlock_exp - static void timer_sync_wait_running(struct timer_base *base) - { - if (atomic_read(&base->timer_waiters)) { -+ raw_spin_unlock_irq(&base->lock); - spin_unlock(&base->expiry_lock); - spin_lock(&base->expiry_lock); -+ raw_spin_lock_irq(&base->lock); - } - } - -@@ -1490,14 +1492,14 @@ static void expire_timers(struct timer_b - if (timer->flags & TIMER_IRQSAFE) { - raw_spin_unlock(&base->lock); - call_timer_fn(timer, fn, baseclk); -- base->running_timer = NULL; - raw_spin_lock(&base->lock); -+ base->running_timer = NULL; - } else { - raw_spin_unlock_irq(&base->lock); - call_timer_fn(timer, fn, baseclk); -+ raw_spin_lock_irq(&base->lock); - base->running_timer = NULL; - timer_sync_wait_running(base); -- raw_spin_lock_irq(&base->lock); - } - } - }