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From: "Denis V. Lunev" <den@openvz.org>
To: <akpm@linux-foundation.org>
Cc: <linux-kernel@vger.kernel.org>, <linux-scsi@vger.kernel.org>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	"James E.J. Bottomley" <James.Bottomley@suse.de>,
	"Denis V. Lunev" <den@openvz.org>
Subject: [PATCH 1/2] Crash in linux kernel when disconnecting usb storage
Date: Tue, 3 Nov 2009 12:36:35 +0300	[thread overview]
Message-ID: <1257240996-23118-1-git-send-email-den@openvz.org> (raw)

From: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>

__scsi_remove_device() in scsi_forget_host() is executed out of scan_mutex
and races with scsi_destroy_sdev() <- scsi_sysfs_add_devices()
<- scsi_finish_async_scan(). The result is use after free and/or
double free, oops.

The fix is simple, move scsi_forget_host() under scan_mutex.

scsi_forget_host() is just sequence of __scsi_remove_device().
All another calls of __scsi_remove_device() are made under scan_mutex.
So that it is safe.

Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
CC: James E.J. Bottomley <James.Bottomley@suse.de>
Signed-off-by: Denis V. Lunev <den@openvz.org>
---
 drivers/scsi/hosts.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 5fd2da4..c968cc3 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -164,8 +164,8 @@ void scsi_remove_host(struct Scsi_Host *shost)
 			return;
 		}
 	spin_unlock_irqrestore(shost->host_lock, flags);
-	mutex_unlock(&shost->scan_mutex);
 	scsi_forget_host(shost);
+	mutex_unlock(&shost->scan_mutex);
 	scsi_proc_host_rm(shost);
 
 	spin_lock_irqsave(shost->host_lock, flags);
-- 
1.6.4.4


WARNING: multiple messages have this Message-ID (diff)
From: "Denis V. Lunev" <den@openvz.org>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	"James E.J. Bottomley" <James.Bottomley@suse.de>,
	"Denis V. Lunev" <den@openvz.org>
Subject: [PATCH 1/2] Crash in linux kernel when disconnecting usb storage
Date: Tue, 3 Nov 2009 12:36:35 +0300	[thread overview]
Message-ID: <1257240996-23118-1-git-send-email-den@openvz.org> (raw)

From: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>

__scsi_remove_device() in scsi_forget_host() is executed out of scan_mutex
and races with scsi_destroy_sdev() <- scsi_sysfs_add_devices()
<- scsi_finish_async_scan(). The result is use after free and/or
double free, oops.

The fix is simple, move scsi_forget_host() under scan_mutex.

scsi_forget_host() is just sequence of __scsi_remove_device().
All another calls of __scsi_remove_device() are made under scan_mutex.
So that it is safe.

Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
CC: James E.J. Bottomley <James.Bottomley@suse.de>
Signed-off-by: Denis V. Lunev <den@openvz.org>
---
 drivers/scsi/hosts.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 5fd2da4..c968cc3 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -164,8 +164,8 @@ void scsi_remove_host(struct Scsi_Host *shost)
 			return;
 		}
 	spin_unlock_irqrestore(shost->host_lock, flags);
-	mutex_unlock(&shost->scan_mutex);
 	scsi_forget_host(shost);
+	mutex_unlock(&shost->scan_mutex);
 	scsi_proc_host_rm(shost);
 
 	spin_lock_irqsave(shost->host_lock, flags);
-- 
1.6.4.4


             reply	other threads:[~2009-11-03  9:52 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-03  9:36 Denis V. Lunev [this message]
2009-11-03  9:36 ` [PATCH 1/2] Crash in linux kernel when disconnecting usb storage Denis V. Lunev
2009-11-03  9:36 ` [PATCH 2/2] Another crash in linux kernel at diconnect of usb strorage Denis V. Lunev
2009-11-03  9:36   ` Denis V. Lunev

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