Re: VFS deadlock ?

From: Dave Jones
Date: Thu Mar 21 2013 - 19:07:55 EST


On Thu, Mar 21, 2013 at 03:53:13PM -0700, Linus Torvalds wrote:
> On Thu, Mar 21, 2013 at 3:12 PM, Dave Jones <davej@xxxxxxxxxx> wrote:
> >
> > it's not just irda fwiw..
> >
> > p1=rpc p2=rpc p1parent=net p2parent=net
>
> Ok, good. The only rpc/irda that has something in common is
> /proc/net/, and they both use proc_mkdir() to create the directory:
>
> proc_irda = proc_mkdir("irda", init_net.proc_net);
> ...
> sn->proc_net_rpc = proc_mkdir("rpc", net->proc_net);
>
> so it's almost certainly that case. What I do *not* see is how we got
> two different dentries for the same name in /proc. But if that
> happens, then yes, they will have aliased inodes (because
> proc_get_inode() will look them up by "sb,de->low_ino".
>
> Al, any ideas? There shouldn't be some lookup race, because that's
> done under the parent inode lock. And multiple mount-points will have
> different superblocks, so proc_get_inode() will give them separate
> inodes. And bind mounts should have all the same dentry tree. So what
> the heck am I missing?

Hmm, these also seem to have appeared around about the time I reenabled
all the namespace options after Eric fixed that last proc bug.

could that be related ?

Dave
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