Messages in this thread | | | Date | Wed, 16 May 2007 17:40:53 +0200 | From | Tejun Heo <> | Subject | Re: Oops and Panics in 2.6.21.1, 2.6.20.6 and 2.6.19.2 |
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Andrew Morton wrote: >>> a number of people have hit that, on and off. >> Yeah, I've been seeing that one. It should have been fixed with the big >> fat patchset. > > Great - fingers crossed. > >>> We were close to having a fix, I think, but then we decided that great >>> chunks of sysfs needed rewriting and I believe that we believe that this >>> great rewrite will fix this bug. >> How were we gonna fix it? If it isn't too complex, I can cook up a >> patch for -stable series. > > Do we actually understand the causes?
Yeah, I think I do. Basically, the problem is that on-demand attach and reclamation update sd->s_dentry but accesses to it aren't synchronized properly. In the big fat patchset, first I tried to fix it by removing sd->s_dentry completely which didn't work because of shadow nodes, so the second try was to fix the synchronization which is in -mm now.
>> The safest approach I can think of is making >> dentries for attributes unreclaimable but those are made reclaimable for >> good reasons. :-( > > Yeah, that was the google workaround. It's OK unless you happen to have > thousands of disks on an ia32 box.
I see. I thought there was different approach on fixing the problem. I'll try to backport the synchronization fix but am afraid it can be too risky for -stable. If it seems too risky, I'll send a patch to disable reclamation.
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