linux-kernel - [PATCH] Xen: Fix warning when hot-unplugging virtual block devices

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 21 Aug 2008 12:37:23 +0100
From:	Alex Nixon <alex.nixon@...rix.com>
To:	Jeremy Fitzhardinge <Jeremy.Fitzhardinge@...rix.com>
CC:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [PATCH] Xen: Fix warning when hot-unplugging virtual block devices

From: Alex Nixon <alex.nixon@...rix.com>
Date: Thu, 21 Aug 2008 12:30:54 +0100
Subject: [PATCH] Xen: Fix warning when hot-unplugging virtual block devices

WARNING: at kernel/softirq.c:136 local_bh_enable+0x3f/0x8a()

del_gendisk needs IRQs enabled, as the code path eventually reaches local_bh_enable.
blk_stop_queue needs them disabled - so do so temporarily.

It shouldn't matter if an interrupt comes in whilst blkif_io_lock is held, as it will block on the lock.  Upon acquisition, it'll realise the device is down and exit cleanly.

Signed-off-by: Alex Nixon <alex.nixon@...rix.com>
---
 drivers/block/xen-blkfront.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index d5e7532..95cee2c 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -899,16 +899,18 @@ static void blkfront_closing(struct xenbus_device *dev)
 	if (info->rq == NULL)
 		goto out;
 
-	spin_lock_irqsave(&blkif_io_lock, flags);
+	spin_lock(&blkif_io_lock);
 
 	del_gendisk(info->gd);
 
+	local_irq_save(flags);
 	/* No more blkif_request(). */
 	blk_stop_queue(info->rq);
+	local_irq_restore(flags);
 
 	/* No more gnttab callback work. */
 	gnttab_cancel_free_callback(&info->callback);
-	spin_unlock_irqrestore(&blkif_io_lock, flags);
+	spin_unlock(&blkif_io_lock);
 
 	/* Flush gnttab callback work. Must be done with no locks held. */
 	flush_scheduled_work();
-- 
1.5.4.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/