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From: Brian King <brking@linux.vnet.ibm.com>
To: linux-scsi@vger.kernel.org
Cc: tyreld@linux.ibm.com, linuxppc-dev@lists.ozlabs.org,
	martin.petersen@oracle.com,
	Brian King <brking@linux.vnet.ibm.com>
Subject: [PATCH] ibmvfc: Protect vhost->task_set increment by the host lock
Date: Wed, 16 Sep 2020 15:09:59 -0500	[thread overview]
Message-ID: <1600286999-22059-1-git-send-email-brking@linux.vnet.ibm.com> (raw)

In the discovery thread, ibmvfc does a vhost->task_set++ without
any lock held. This could result in two targets getting the same
cancel key, which could have strange effects in error recovery.
The actual probability of this occurring should be extremely
small, since this should all be done in a single threaded loop
from the discovery thread, but let's fix it up anyway to be safe.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
---
 drivers/scsi/ibmvscsi/ibmvfc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index 322bb30..b393587 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -4169,11 +4169,11 @@ static int ibmvfc_alloc_target(struct ibmvfc_host *vhost,struct ibmvfc_discover_
 	tgt->wwpn = wwpn;
 	tgt->vhost = vhost;
 	tgt->need_login = 1;
-	tgt->cancel_key = vhost->task_set++;
 	timer_setup(&tgt->timer, ibmvfc_adisc_timeout, 0);
 	kref_init(&tgt->kref);
 	ibmvfc_init_tgt(tgt, ibmvfc_tgt_implicit_logout);
 	spin_lock_irqsave(vhost->host->host_lock, flags);
+	tgt->cancel_key = vhost->task_set++;
 	list_add_tail(&tgt->queue, &vhost->targets);
 
 unlock_out:
-- 
1.8.3.1


WARNING: multiple messages have this Message-ID (diff)
From: Brian King <brking@linux.vnet.ibm.com>
To: linux-scsi@vger.kernel.org
Cc: Brian King <brking@linux.vnet.ibm.com>,
	tyreld@linux.ibm.com, linuxppc-dev@lists.ozlabs.org,
	martin.petersen@oracle.com
Subject: [PATCH] ibmvfc: Protect vhost->task_set increment by the host lock
Date: Wed, 16 Sep 2020 15:09:59 -0500	[thread overview]
Message-ID: <1600286999-22059-1-git-send-email-brking@linux.vnet.ibm.com> (raw)

In the discovery thread, ibmvfc does a vhost->task_set++ without
any lock held. This could result in two targets getting the same
cancel key, which could have strange effects in error recovery.
The actual probability of this occurring should be extremely
small, since this should all be done in a single threaded loop
from the discovery thread, but let's fix it up anyway to be safe.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
---
 drivers/scsi/ibmvscsi/ibmvfc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index 322bb30..b393587 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -4169,11 +4169,11 @@ static int ibmvfc_alloc_target(struct ibmvfc_host *vhost,struct ibmvfc_discover_
 	tgt->wwpn = wwpn;
 	tgt->vhost = vhost;
 	tgt->need_login = 1;
-	tgt->cancel_key = vhost->task_set++;
 	timer_setup(&tgt->timer, ibmvfc_adisc_timeout, 0);
 	kref_init(&tgt->kref);
 	ibmvfc_init_tgt(tgt, ibmvfc_tgt_implicit_logout);
 	spin_lock_irqsave(vhost->host->host_lock, flags);
+	tgt->cancel_key = vhost->task_set++;
 	list_add_tail(&tgt->queue, &vhost->targets);
 
 unlock_out:
-- 
1.8.3.1


             reply	other threads:[~2020-09-16 20:11 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-16 20:09 Brian King [this message]
2020-09-16 20:09 ` [PATCH] ibmvfc: Protect vhost->task_set increment by the host lock Brian King
2020-09-22 21:39 ` Martin K. Petersen
2020-09-22 21:39   ` Martin K. Petersen
2020-09-30  3:34 ` Martin K. Petersen
2020-09-30  3:34   ` Martin K. Petersen

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