From: Ming Lei <ming.lei@redhat.com>
To: Gulam Mohamed <gulam.mohamed@oracle.com>
Cc: "hch@infradead.org" <hch@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
Junxiao Bi <junxiao.bi@oracle.com>,
Martin Petersen <martin.petersen@oracle.com>,
"axboe@kernel.dk" <axboe@kernel.dk>
Subject: Re: Race condition in Kernel
Date: Thu, 25 Mar 2021 09:46:13 +0800 [thread overview]
Message-ID: <YFvrZUzmdLpj7E4F@T590> (raw)
In-Reply-To: <CO1PR10MB4563A6404AD789EEF93F995798639@CO1PR10MB4563.namprd10.prod.outlook.com>
On Wed, Mar 24, 2021 at 12:37:03PM +0000, Gulam Mohamed wrote:
> Hi All,
>
> We are facing a stale link (of the device) issue during the iscsi-logout process if we use parted command just before the iscsi logout. Here are the details:
>
> As part of iscsi logout, the partitions and the disk will be removed. The parted command, used to list the partitions, will open the disk in RW mode which results in systemd-udevd re-reading the partitions. This will trigger the rescan partitions which will also delete and re-add the partitions. So, both iscsi logout processing and the parted (through systemd-udevd) will be involved in add/delete of partitions. In our case, the following sequence of operations happened (the iscsi device is /dev/sdb with partition sdb1):
>
> 1. sdb1 was removed by PARTED
> 2. kworker, as part of iscsi logout, couldn't remove sdb1 as it was already removed by PARTED
> 3. sdb1 was added by parted
After kworker is started for logout, I guess all IOs are supposed to be failed
at that time, so just wondering why 'sdb1' is still added by parted(systemd-udev)?
ioctl(BLKRRPART) needs to read partition table for adding back partitions, if IOs
are failed by iscsi logout, I guess the issue can be avoided too?
--
Ming
next prev parent reply other threads:[~2021-03-25 1:47 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-24 12:37 Race condition in Kernel Gulam Mohamed
2021-03-25 0:37 ` Ming Lei
2021-03-25 0:58 ` Junxiao Bi
2021-03-25 1:46 ` Ming Lei [this message]
2021-04-01 16:27 ` Gulam Mohamed
2021-04-02 2:38 ` Ming Lei
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