From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:50075 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755564AbcBXDn4 (ORCPT ); Tue, 23 Feb 2016 22:43:56 -0500 Subject: Patch "scsi: restart list search after unlock in scsi_remove_target" has been added to the 3.14-stable tree To: hch@lst.de, JBottomley@Odin.com, JBottomley@Parallels.com, dan.j.williams@intel.com, djbw@fb.com, gregkh@linuxfoundation.org, jthumshirn@suse.de Cc: , From: Date: Tue, 23 Feb 2016 19:23:54 -0800 Message-ID: <14562842341252@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled scsi: restart list search after unlock in scsi_remove_target to the 3.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: scsi-restart-list-search-after-unlock-in-scsi_remove_target.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 40998193560dab6c3ce8d25f4fa58a23e252ef38 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 19 Oct 2015 16:35:46 +0200 Subject: scsi: restart list search after unlock in scsi_remove_target From: Christoph Hellwig commit 40998193560dab6c3ce8d25f4fa58a23e252ef38 upstream. When dropping a lock while iterating a list we must restart the search as other threads could have manipulated the list under us. Without this we can get stuck in an endless loop. This bug was introduced by commit bc3f02a795d3b4faa99d37390174be2a75d091bd Author: Dan Williams Date: Tue Aug 28 22:12:10 2012 -0700 [SCSI] scsi_remove_target: fix softlockup regression on hot remove Which was itself trying to fix a reported soft lockup issue http://thread.gmane.org/gmane.linux.kernel/1348679 However, we believe even with this revert of the original patch, the soft lockup problem has been fixed by commit f2495e228fce9f9cec84367547813cbb0d6db15a Author: James Bottomley Date: Tue Jan 21 07:01:41 2014 -0800 [SCSI] dual scan thread bug fix Thanks go to Dan Williams for tracking all this prior history down. Reported-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Tested-by: Johannes Thumshirn Reviewed-by: Johannes Thumshirn Fixes: bc3f02a795d3b4faa99d37390174be2a75d091bd Signed-off-by: James Bottomley Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/scsi_sysfs.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -1123,31 +1123,23 @@ static void __scsi_remove_target(struct void scsi_remove_target(struct device *dev) { struct Scsi_Host *shost = dev_to_shost(dev->parent); - struct scsi_target *starget, *last = NULL; + struct scsi_target *starget; unsigned long flags; - /* remove targets being careful to lookup next entry before - * deleting the last - */ +restart: spin_lock_irqsave(shost->host_lock, flags); list_for_each_entry(starget, &shost->__targets, siblings) { if (starget->state == STARGET_DEL) continue; if (starget->dev.parent == dev || &starget->dev == dev) { - /* assuming new targets arrive at the end */ kref_get(&starget->reap_ref); spin_unlock_irqrestore(shost->host_lock, flags); - if (last) - scsi_target_reap(last); - last = starget; __scsi_remove_target(starget); - spin_lock_irqsave(shost->host_lock, flags); + scsi_target_reap(starget); + goto restart; } } spin_unlock_irqrestore(shost->host_lock, flags); - - if (last) - scsi_target_reap(last); } EXPORT_SYMBOL(scsi_remove_target); Patches currently in stable-queue which might be from hch@lst.de are queue-3.14/scsi-restart-list-search-after-unlock-in-scsi_remove_target.patch queue-3.14/iscsi-target-fix-potential-dead-lock-during-node-acl-delete.patch queue-3.14/fix-a-memory-leak-in-scsi_host_dev_release.patch