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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Julien Grall <julien@xen.org>,
	Juergen Gross <jgross@suse.com>,
	Boris Ostrovsky <boris.ostrvsky@oracle.com>
Subject: [PATCH 4.14 25/25] xen/events: reset active flag for lateeoi events later
Date: Fri,  9 Jul 2021 15:18:56 +0200	[thread overview]
Message-ID: <20210709131643.055966920@linuxfoundation.org> (raw)
In-Reply-To: <20210709131627.928131764@linuxfoundation.org>

From: Juergen Gross <jgross@suse.com>

commit 3de218ff39b9e3f0d453fe3154f12a174de44b25 upstream.

In order to avoid a race condition for user events when changing
cpu affinity reset the active flag only when EOI-ing the event.

This is working fine as all user events are lateeoi events. Note that
lateeoi_ack_mask_dynirq() is not modified as there is no explicit call
to xen_irq_lateeoi() expected later.

Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Fixes: b6622798bc50b62 ("xen/events: avoid handling the same event on two cpus at the same time")
Tested-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrvsky@oracle.com>
Link: https://lore.kernel.org/r/20210623130913.9405-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/xen/events/events_base.c |   23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -524,6 +524,9 @@ static void xen_irq_lateeoi_locked(struc
 	}
 
 	info->eoi_time = 0;
+
+	/* is_active hasn't been reset yet, do it now. */
+	smp_store_release(&info->is_active, 0);
 	do_unmask(info, EVT_MASK_REASON_EOI_PENDING);
 }
 
@@ -1780,10 +1783,22 @@ static void lateeoi_ack_dynirq(struct ir
 	struct irq_info *info = info_for_irq(data->irq);
 	evtchn_port_t evtchn = info ? info->evtchn : 0;
 
-	if (VALID_EVTCHN(evtchn)) {
-		do_mask(info, EVT_MASK_REASON_EOI_PENDING);
-		ack_dynirq(data);
-	}
+	if (!VALID_EVTCHN(evtchn))
+		return;
+
+	do_mask(info, EVT_MASK_REASON_EOI_PENDING);
+
+	if (unlikely(irqd_is_setaffinity_pending(data)) &&
+	    likely(!irqd_irq_disabled(data))) {
+		do_mask(info, EVT_MASK_REASON_TEMPORARY);
+
+		clear_evtchn(evtchn);
+
+		irq_move_masked_irq(data);
+
+		do_unmask(info, EVT_MASK_REASON_TEMPORARY);
+	} else
+		clear_evtchn(evtchn);
 }
 
 static void lateeoi_mask_ack_dynirq(struct irq_data *data)



  parent reply	other threads:[~2021-07-09 13:20 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-09 13:18 [PATCH 4.14 00/25] 4.14.239-rc1 review Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 01/25] include/linux/mmdebug.h: make VM_WARN* non-rvals Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 02/25] mm: add VM_WARN_ON_ONCE_PAGE() macro Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 03/25] mm/rmap: remove unneeded semicolon in page_not_mapped() Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 04/25] mm/rmap: use page_not_mapped in try_to_unmap() Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 05/25] mm/thp: try_to_unmap() use TTU_SYNC for safe splitting Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 06/25] mm/thp: fix vma_address() if virtual address below file offset Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 07/25] mm/thp: fix page_address_in_vma() on file THP tails Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 08/25] mm: thp: replace DEBUG_VM BUG with VM_WARN when unmap fails for split Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 09/25] mm: page_vma_mapped_walk(): use page for pvmw->page Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 10/25] mm: page_vma_mapped_walk(): settle PageHuge on entry Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 11/25] mm: page_vma_mapped_walk(): use pmde for *pvmw->pmd Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 12/25] mm: page_vma_mapped_walk(): prettify PVMW_MIGRATION block Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 13/25] mm: page_vma_mapped_walk(): crossing page table boundary Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 14/25] mm: page_vma_mapped_walk(): add a level of indentation Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 15/25] mm: page_vma_mapped_walk(): use goto instead of while (1) Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 16/25] mm: page_vma_mapped_walk(): get vma_address_end() earlier Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 17/25] mm/thp: fix page_vma_mapped_walk() if THP mapped by ptes Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 18/25] mm/thp: another PVMW_SYNC fix in page_vma_mapped_walk() Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 19/25] mm, futex: fix shared futex pgoff on shmem huge page Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 20/25] scsi: sr: Return appropriate error code when disk is ejected Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 21/25] drm/nouveau: fix dma_address check for CPU/GPU sync Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 22/25] kfifo: DECLARE_KIFO_PTR(fifo, u64) does not work on arm 32 bit Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 23/25] kthread_worker: split code for canceling the delayed work timer Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 24/25] kthread: prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync() Greg Kroah-Hartman
2021-07-09 13:18 ` Greg Kroah-Hartman [this message]
2021-07-10 14:05 ` [PATCH 4.14 00/25] 4.14.239-rc1 review Naresh Kamboju
2021-07-10 19:51 ` Guenter Roeck
2021-07-12  0:57 ` Samuel Zou

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