From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CBA7111C88 for ; Mon, 12 Jun 2023 10:43:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 54FBCC433EF; Mon, 12 Jun 2023 10:43:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1686566584; bh=Tj5pIUHrwKbgZKMQUQA49EpM6LyQZLQbHXh/SbjZEW4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=y6h6WLM7AgihR+RjXXxyMYs7HgN1LNqCq3ZoneZnsqOldQwrH3TWuvZpXT5iy8e3e 89MlyHLFEx39Gb5/8qjZ7pmhd2fUyIgkK+iwJQf9YDA6/GBbtIbnMZK2mO+fh+y1UO TS1OJbCUFaauIK/sXCGd3OKD5tbR7Lc2UnaHGQAI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Jan=20H=C3=B6ppner?= , Stefan Haberland , Jens Axboe Subject: [PATCH 6.1 087/132] s390/dasd: Use correct lock while counting channel queue length Date: Mon, 12 Jun 2023 12:27:01 +0200 Message-ID: <20230612101714.230735749@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230612101710.279705932@linuxfoundation.org> References: <20230612101710.279705932@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Jan Höppner commit ccc45cb4e7271c74dbb27776ae8f73d84557f5c6 upstream. The lock around counting the channel queue length in the BIODASDINFO ioctl was incorrectly changed to the dasd_block->queue_lock with commit 583d6535cb9d ("dasd: remove dead code"). This can lead to endless list iterations and a subsequent crash. The queue_lock is supposed to be used only for queue lists belonging to dasd_block. For dasd_device related queue lists the ccwdev lock must be used. Fix the mentioned issues by correctly using the ccwdev lock instead of the queue lock. Fixes: 583d6535cb9d ("dasd: remove dead code") Cc: stable@vger.kernel.org # v5.0+ Signed-off-by: Jan Höppner Reviewed-by: Stefan Haberland Signed-off-by: Stefan Haberland Link: https://lore.kernel.org/r/20230609153750.1258763-2-sth@linux.ibm.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/s390/block/dasd_ioctl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/s390/block/dasd_ioctl.c +++ b/drivers/s390/block/dasd_ioctl.c @@ -552,10 +552,10 @@ static int __dasd_ioctl_information(stru memcpy(dasd_info->type, base->discipline->name, 4); - spin_lock_irqsave(&block->queue_lock, flags); + spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags); list_for_each(l, &base->ccw_queue) dasd_info->chanq_len++; - spin_unlock_irqrestore(&block->queue_lock, flags); + spin_unlock_irqrestore(get_ccwdev_lock(base->cdev), flags); return 0; }