Messages in this thread | | | Subject | Re: md deadlock (was Re: 2.6.18-mm2) | From | Peter Zijlstra <> | Date | Fri, 29 Sep 2006 16:03:17 +0200 |
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On Fri, 2006-09-29 at 22:52 +1000, Neil Brown wrote: > On Friday September 29, a.p.zijlstra@chello.nl wrote: > > On Thu, 2006-09-28 at 13:54 +0200, Michal Piotrowski wrote: > > > > Looks like a real deadlock here. It seems to me #2 is the easiest to > > break. > > I guess it could deadlock if you tried to add /dev/md0 as a component > of /dev/md0. I should probably check for that somewhere. > In other cases the array->member ordering ensures there is no > deadlock. >
1 2
open(/dev/md0)
open(/dev/md0) - do_open() -> bdev->bd_mutex ioctl(/dev/md0, hotadd) - md_ioctl() -> mddev->reconfig_mutex -- hot_add_disk() --- bind_rdev_to_array() ---- bd_claim_by_disk() ----- bd_claim_by_kobject() -- md_open() --- mddev_lock() ---- mutex_lock(mddev->reconfig_mutex) ------ mutex_lock(bdev->bd_mutex)
looks like an AB-BA deadlock to me
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