Messages in this thread | | | Date | Wed, 2 Jan 2013 11:01:15 -0500 | From | Chris Mason <> | Subject | Re: memory corruption, possibly caused by i915 |
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On Wed, Jan 02, 2013 at 08:52:33AM -0700, Dave Jones wrote: > We've had a increased number of reports in the last six months or so > from Fedora users getting corrupted page tables. > At first I wrote it off to bad hardware, but they started happening frequently > enough that I began to wonder if it was a real problem. > > The only common thing I could think of was that now that gnome-shell is > our default desktop, we're making a lot more use of DRI than we used to. > > To test a hypothesis, I played a whole lot of quake3 over the holidays, > and was finally able to make it happen too. > > After playing the game for a few hours, I exited it, and all was well. > But when I then went to shut down the laptop, I saw this.. > > [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] > [52460.286556] Pid: 1317, comm: panel-6-systray Not tainted 3.7.0+ #15 > [52460.286926] Call Trace: > [52460.287086] [<ffffffff8114c662>] print_bad_pte+0x1e2/0x250 > [52460.287445] [<ffffffff8114ea1d>] unmap_single_vma+0x5dd/0x8a0 > [52460.287804] [<ffffffff8114f541>] unmap_vmas+0x51/0xa0 > [52460.288087] [<ffffffff81158628>] exit_mmap+0x98/0x170 > [52460.288388] [<ffffffff81047808>] mmput+0x78/0xe0 > [52460.288651] [<ffffffff8104ffae>] do_exit+0x24e/0xa30 > [52460.288944] [<ffffffff8119394e>] ? ____fput+0xe/0x10 > [52460.289268] [<ffffffff8106af3c>] ? task_work_run+0xac/0xe0 > [52460.289608] [<ffffffff8105081f>] do_group_exit+0x3f/0xa0 > [52460.289937] [<ffffffff81050897>] sys_exit_group+0x17/0x20 > [52460.290288] [<ffffffff815f5699>] system_call_fastpath+0x16/0x1b > > 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.
Hi Dave,
It's a btrfs file, but this isn't in our mmap op. The traces are finding bad pages at unmap time.
> > 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.
-chris
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