Messages in this thread | | | Date | Tue, 14 Mar 2023 21:55:08 +0800 | Subject | Re: md_raid: mdX_raid6 looping after sync_action "check" to "idle" transition | From | Guoqing Jiang <> |
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On 3/14/23 21:25, Marc Smith wrote: > On Mon, Feb 8, 2021 at 7:49 PM Guoqing Jiang > <guoqing.jiang@cloud.ionos.com> wrote: >> Hi Donald, >> >> On 2/8/21 19:41, Donald Buczek wrote: >>> Dear Guoqing, >>> >>> On 08.02.21 15:53, Guoqing Jiang wrote: >>>> >>>> On 2/8/21 12:38, Donald Buczek wrote: >>>>>> 5. maybe don't hold reconfig_mutex when try to unregister >>>>>> sync_thread, like this. >>>>>> >>>>>> /* resync has finished, collect result */ >>>>>> mddev_unlock(mddev); >>>>>> md_unregister_thread(&mddev->sync_thread); >>>>>> mddev_lock(mddev); >>>>> As above: While we wait for the sync thread to terminate, wouldn't it >>>>> be a problem, if another user space operation takes the mutex? >>>> I don't think other places can be blocked while hold mutex, otherwise >>>> these places can cause potential deadlock. Please try above two lines >>>> change. And perhaps others have better idea. >>> Yes, this works. No deadlock after >11000 seconds, >>> >>> (Time till deadlock from previous runs/seconds: 1723, 37, 434, 1265, >>> 3500, 1136, 109, 1892, 1060, 664, 84, 315, 12, 820 ) >> Great. I will send a formal patch with your reported-by and tested-by. >> >> Thanks, >> Guoqing > I'm still hitting this issue with Linux 5.4.229 -- it looks like 1/2 > of the patches that supposedly resolve this were applied to the stable > kernels, however, one was omitted due to a regression: > md: don't unregister sync_thread with reconfig_mutex held (upstream > commit 8b48ec23cc51a4e7c8dbaef5f34ebe67e1a80934) > > I don't see any follow-up on the thread from June 8th 2022 asking for > this patch to be dropped from all stable kernels since it caused a > regression. > > The patch doesn't appear to be present in the current mainline kernel > (6.3-rc2) either. So I assume this issue is still present there, or it > was resolved differently and I just can't find the commit/patch.
It should be fixed by commit 9dfbdafda3b3"md: unlock mddev before reap sync_thread in action_store".
Thanks, Guoqing
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