mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-04-29 05:52:38 -04:00
d1d90147c9
Since commit4ad23a9764("MD: use per-cpu counter for writes_pending"), the wait_queue is only got invoked if THREAD_WAKEUP is not set previously. With above change, I can see process_metadata_update could always hang on the wait queue, because mddev->thread could stay on 'D' status and the THREAD_WAKEUP flag is not cleared since there are lots of place to wake up mddev->thread. Then deadlock happened as follows: linux175:~ # ps aux|grep md|grep D root 20117 0.0 0.0 0 0 ? D 03:45 0:00 [md0_raid1] root 20125 0.0 0.0 0 0 ? D 03:45 0:00 [md0_cluster_rec] linux175:~ # cat /proc/20117/stack [<ffffffffa0635604>] dlm_lock_sync+0x94/0xd0 [md_cluster] [<ffffffffa0635674>] lock_token+0x34/0xd0 [md_cluster] [<ffffffffa0635804>] metadata_update_start+0x64/0x110 [md_cluster] [<ffffffffa04d985b>] md_update_sb.part.58+0x9b/0x860 [md_mod] [<ffffffffa04da035>] md_update_sb+0x15/0x30 [md_mod] [<ffffffffa04dc066>] md_check_recovery+0x266/0x490 [md_mod] [<ffffffffa06450e2>] raid1d+0x42/0x810 [raid1] [<ffffffffa04d2252>] md_thread+0x122/0x150 [md_mod] [<ffffffff81091741>] kthread+0x101/0x140 linux175:~ # cat /proc/20125/stack [<ffffffffa0636679>] recv_daemon+0x3f9/0x5c0 [md_cluster] [<ffffffffa04d2252>] md_thread+0x122/0x150 [md_mod] [<ffffffff81091741>] kthread+0x101/0x140 So let's revert the part of code in the commit to resovle the problem since we can't get lots of benefits of previous change. Fixes:4ad23a9764("MD: use per-cpu counter for writes_pending") Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.