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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Halil Pasic <pasic@linux.ibm.com>,
	Marc Hartmayer <mhartmay@linux.ibm.com>,
	Cornelia Huck <cohuck@redhat.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Sasha Levin <sashal@kernel.org>,
	linux-s390@vger.kernel.org,
	virtualization@lists.linux-foundation.org, kvm@vger.kernel.org
Subject: [PATCH AUTOSEL 4.19 162/167] virtio/s390: fix race on airq_areas[]
Date: Tue,  3 Sep 2019 12:25:14 -0400	[thread overview]
Message-ID: <20190903162519.7136-162-sashal@kernel.org> (raw)
In-Reply-To: <20190903162519.7136-1-sashal@kernel.org>

From: Halil Pasic <pasic@linux.ibm.com>

[ Upstream commit 4f419eb14272e0698e8c55bb5f3f266cc2a21c81 ]

The access to airq_areas was racy ever since the adapter interrupts got
introduced to virtio-ccw, but since commit 39c7dcb15892 ("virtio/s390:
make airq summary indicators DMA") this became an issue in practice as
well. Namely before that commit the airq_info that got overwritten was
still functional. After that commit however the two infos share a
summary_indicator, which aggravates the situation. Which means
auto-online mechanism occasionally hangs the boot with virtio_blk.

Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 96b14536d935 ("virtio-ccw: virtio-ccw adapter interrupt support.")
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/s390/virtio/virtio_ccw.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index ec54538f7ae1c..67efdf25657f3 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -132,6 +132,7 @@ struct airq_info {
 	struct airq_iv *aiv;
 };
 static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
+static DEFINE_MUTEX(airq_areas_lock);
 
 #define CCW_CMD_SET_VQ 0x13
 #define CCW_CMD_VDEV_RESET 0x33
@@ -244,9 +245,11 @@ static unsigned long get_airq_indicator(struct virtqueue *vqs[], int nvqs,
 	unsigned long bit, flags;
 
 	for (i = 0; i < MAX_AIRQ_AREAS && !indicator_addr; i++) {
+		mutex_lock(&airq_areas_lock);
 		if (!airq_areas[i])
 			airq_areas[i] = new_airq_info();
 		info = airq_areas[i];
+		mutex_unlock(&airq_areas_lock);
 		if (!info)
 			return 0;
 		write_lock_irqsave(&info->lock, flags);
-- 
2.20.1


      parent reply	other threads:[~2019-09-03 16:32 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190903162519.7136-1-sashal@kernel.org>
2019-09-03 16:22 ` [PATCH AUTOSEL 4.19 011/167] KVM: x86: hyperv: enforce vp_index < KVM_MAX_VCPUS Sasha Levin
2019-09-03 16:22 ` [PATCH AUTOSEL 4.19 012/167] KVM: x86: hyperv: consistently use 'hv_vcpu' for 'struct kvm_vcpu_hv' variables Sasha Levin
2019-09-03 16:22 ` [PATCH AUTOSEL 4.19 013/167] KVM: x86: hyperv: keep track of mismatched VP indexes Sasha Levin
2019-09-03 16:22 ` [PATCH AUTOSEL 4.19 014/167] KVM: hyperv: define VP assist page helpers Sasha Levin
2019-09-03 16:22 ` [PATCH AUTOSEL 4.19 015/167] x86/kvm/lapic: preserve gfn_to_hva_cache len on cache reinit Sasha Levin
2019-09-03 16:23 ` [PATCH AUTOSEL 4.19 065/167] KVM: VMX: Compare only a single byte for VMCS' "launched" in vCPU-run Sasha Levin
2019-09-03 16:23 ` [PATCH AUTOSEL 4.19 073/167] x86/kvmclock: set offset for kvm unstable clock Sasha Levin
2019-09-03 16:24 ` [PATCH AUTOSEL 4.19 092/167] kvm: mmu: Fix overflow on kvm mmu page limit calculation Sasha Levin
2019-09-03 16:24 ` [PATCH AUTOSEL 4.19 093/167] x86/kvm: move kvm_load/put_guest_xcr0 into atomic context Sasha Levin
2019-09-03 16:24 ` [PATCH AUTOSEL 4.19 094/167] KVM: x86: Always use 32-bit SMRAM save state for 32-bit kernels Sasha Levin
2019-09-03 16:24 ` [PATCH AUTOSEL 4.19 115/167] kvm: Check irqchip mode before assign irqfd Sasha Levin
2019-09-03 16:24 ` [PATCH AUTOSEL 4.19 132/167] KVM: x86: optimize check for valid PAT value Sasha Levin
2019-09-03 16:24 ` [PATCH AUTOSEL 4.19 133/167] KVM: VMX: Always signal #GP on WRMSR to MSR_IA32_CR_PAT with bad value Sasha Levin
2019-09-03 16:24 ` [PATCH AUTOSEL 4.19 134/167] KVM: VMX: Fix handling of #MC that occurs during VM-Entry Sasha Levin
2019-09-03 16:24 ` [PATCH AUTOSEL 4.19 135/167] KVM: VMX: check CPUID before allowing read/write of IA32_XSS Sasha Levin
2019-09-03 16:25 ` Sasha Levin [this message]

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