From: Christoph Hellwig <hch@infradead.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: xfs mr_lock vs mmap_sem lock inversion?
Date: Fri, 17 Jul 2009 11:09:22 -0400 [thread overview]
Message-ID: <20090717150922.GA434@infradead.org> (raw)
In-Reply-To: <1247580955.7500.97.camel@twins>
It's a problem in the VM code, which we already discussed a while
ago. The problem is that the VMA manipultation code calls fput
under the mmap_sem, while we can take mmap_sem ue to a page fault
from inside generic_file_aio_read/write. So any filesystem
that nees the same lock held over read/write also in release is
crewed.
Now on the positive side I think we can actually get rid of taking
the iolock in ->release in XFS, but I'm sure other filesystems
might continue hitting similar issues.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: xfs mr_lock vs mmap_sem lock inversion?
Date: Fri, 17 Jul 2009 11:09:22 -0400 [thread overview]
Message-ID: <20090717150922.GA434@infradead.org> (raw)
In-Reply-To: <1247580955.7500.97.camel@twins>
It's a problem in the VM code, which we already discussed a while
ago. The problem is that the VMA manipultation code calls fput
under the mmap_sem, while we can take mmap_sem ue to a page fault
from inside generic_file_aio_read/write. So any filesystem
that nees the same lock held over read/write also in release is
crewed.
Now on the positive side I think we can actually get rid of taking
the iolock in ->release in XFS, but I'm sure other filesystems
might continue hitting similar issues.
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next prev parent reply other threads:[~2009-07-17 15:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-14 14:15 xfs mr_lock vs mmap_sem lock inversion? Peter Zijlstra
2009-07-17 15:09 ` Christoph Hellwig [this message]
2009-07-17 15:09 ` Christoph Hellwig
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