Re: memory corruption, possibly caused by i915

From: Dave Jones
Date: Wed Jan 02 2013 - 11:30:41 EST

On Wed, Jan 02, 2013 at 11:01:15AM -0500, Chris Mason wrote:
> > [52460.280346] BUG: Bad page map in process panel-6-systray pte:ffff8800b665a0e8 pmd:b6659067
> > [52460.280848] addr:00000038bf3fd000 vm_flags:00000070 anon_vma: (null) mapping:ffff88011052fd98 index:1fd
> > [52460.281547] vma->vm_ops->fault: filemap_fault+0x0/0x470
> > [52460.281878] vma->vm_file->f_op->mmap: btrfs_file_mmap+0x0/0x60 [btrfs]
> >
> > It's falling over in btrfs's mmap op, but I think it's just the victim here,
> > of something else corrupting what had been mmaped in the panel process.
> It's a btrfs file, but this isn't in our mmap op. The traces are
> finding bad pages at unmap time.

Sorry, bad wording on my part.

> > Daniel, can you think of additional sanity checks that could be added to
> > the i915 driver ? (Even if at the expense of speed: a CONFIG_DEBUG option
> > to prove correctness would be very worthwhile imo)
> If the bad pages are getting all the way to btrfs,
> CONFIG_DEBUG_PAGE_ALOC may help? You've got lockdep on so maybe you
> already enabled it.

Yeah, already enabled.


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