From 4e46bf89972b9d98a9f282a9fed2359756a5e34e Mon Sep 17 00:00:00 2001
From: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Date: Tue, 17 Nov 2009 14:10:11 -0800
Subject: [SCSI] fix crash when disconnecting usb storage

__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>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
---
 drivers/scsi/hosts.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'drivers/scsi/hosts.c')

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 5fd2da494d08..c968cc31cd86 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);
-- 
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