Commit 4e46bf89 authored Nov 17, 2009 by Alexey Kuznetsov Committed by James Bottomley Nov 26, 2009

[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>

parent 860dc736

drivers/scsi/hosts.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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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