This is a note to let you know that I've just added the patch titled xen/evtchn: Change irq_info lock to raw_spinlock_t to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: xen-evtchn-change-irq_info-lock-to-raw_spinlock_t.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From d120198bd5ff1d41808b6914e1eb89aff937415c Mon Sep 17 00:00:00 2001 From: Luca Fancellu <luca.fancellu@xxxxxxx> Date: Tue, 6 Apr 2021 11:51:04 +0100 Subject: xen/evtchn: Change irq_info lock to raw_spinlock_t From: Luca Fancellu <luca.fancellu@xxxxxxx> commit d120198bd5ff1d41808b6914e1eb89aff937415c upstream. Unmask operation must be called with interrupt disabled, on preempt_rt spin_lock_irqsave/spin_unlock_irqrestore don't disable/enable interrupts, so use raw_* implementation and change lock variable in struct irq_info from spinlock_t to raw_spinlock_t Cc: stable@xxxxxxxxxxxxxxx Fixes: 25da4618af24 ("xen/events: don't unmask an event channel when an eoi is pending") Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx> Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx> Reviewed-by: Wei Liu <wei.liu@xxxxxxxxxx> Link: https://lore.kernel.org/r/20210406105105.10141-1-luca.fancellu@xxxxxxx Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/xen/events/events_base.c | 10 +++++----- drivers/xen/events/events_internal.h | 2 +- 2 files changed, 6 insertions(+), 6 deletions(-) --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -222,7 +222,7 @@ static int xen_irq_info_common_setup(str info->evtchn = evtchn; info->cpu = cpu; info->mask_reason = EVT_MASK_REASON_EXPLICIT; - spin_lock_init(&info->lock); + raw_spin_lock_init(&info->lock); ret = set_evtchn_to_irq(evtchn, irq); if (ret < 0) @@ -374,28 +374,28 @@ static void do_mask(struct irq_info *inf { unsigned long flags; - spin_lock_irqsave(&info->lock, flags); + raw_spin_lock_irqsave(&info->lock, flags); if (!info->mask_reason) mask_evtchn(info->evtchn); info->mask_reason |= reason; - spin_unlock_irqrestore(&info->lock, flags); + raw_spin_unlock_irqrestore(&info->lock, flags); } static void do_unmask(struct irq_info *info, u8 reason) { unsigned long flags; - spin_lock_irqsave(&info->lock, flags); + raw_spin_lock_irqsave(&info->lock, flags); info->mask_reason &= ~reason; if (!info->mask_reason) unmask_evtchn(info->evtchn); - spin_unlock_irqrestore(&info->lock, flags); + raw_spin_unlock_irqrestore(&info->lock, flags); } #ifdef CONFIG_X86 --- a/drivers/xen/events/events_internal.h +++ b/drivers/xen/events/events_internal.h @@ -47,7 +47,7 @@ struct irq_info { unsigned short eoi_cpu; /* EOI must happen on this cpu */ unsigned int irq_epoch; /* If eoi_cpu valid: irq_epoch of event */ u64 eoi_time; /* Time in jiffies when to EOI. */ - spinlock_t lock; + raw_spinlock_t lock; union { unsigned short virq; Patches currently in stable-queue which might be from luca.fancellu@xxxxxxx are queue-4.4/xen-evtchn-change-irq_info-lock-to-raw_spinlock_t.patch