Re: .17rc5 cfq slab corruption.

[Dave Jones <davej@redhat.com>]

On Sat, May 27, 2006 at 09:07:24AM +0200, Jens Axboe wrote:
 > On Fri, May 26 2006, Andrew Morton wrote:
 > > Dave Jones <davej@redhat.com> wrote:
 > > >
 > > > Was playing with googles new picasa toy, which hammered the disks
 > > > hunting out every image file it could find, when this popped out:
 > > > 
 > > > Slab corruption: (Not tainted) start=ffff810012b998c8, len=168
 > > > Redzone: 0x5a2cf071/0x5a2cf071.
 > > > Last user: [<ffffffff8032c319>](cfq_free_io_context+0x2f/0x74)
 > > > 090: 10 bd 28 1b 00 81 ff ff 6b 6b 6b 6b 6b 6b 6b 6b
 > > > Prev obj: start=ffff810012b99808, len=168
 > > > Redzone: 0x5a2cf071/0x5a2cf071.
 > > > Last user: [<ffffffff8032c319>](cfq_free_io_context+0x2f/0x74)
 > > > 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
 > > > 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
 > > > Next obj: start=ffff810012b99988, len=168
 > > > Redzone: 0x5a2cf071/0x5a2cf071.
 > > > Last user: [<ffffffff8032c319>](cfq_free_io_context+0x2f/0x74)
 > > > 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
 > > > 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
 > 
 > Pretty baffling... cfq has been hammered pretty thoroughly over the
 > last months and _nothing_ has shown up except some performance anomalies
 > that are now fixed. Since daves case (at least) seems to be
 > use-after-free, I'll see if I can reproduce with some contrived case.
 > I'm asuming that picasa forks and exits a lot with submitted io in
 > between than may not have finished at exit.

The second time I hit it, was actually during boot up.

		Dave

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