Re: .17rc5 cfq slab corruption.

[Dave Jones <davej@redhat.com>]

On Fri, May 26, 2006 at 10:56:23PM -0400, Dave Jones wrote:
 > On Fri, May 26, 2006 at 05:39:15PM -0400, Dave Jones 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
 > 
 > After a reboot, I just hit this again.  This time whilst the box was
 > mostly idle (just picking up some email via fetchmail)
 > 
 > Slab corruption: (Not tainted) start=ffff81003dcde8c8, len=168
 > Redzone: 0x5a2cf071/0x5a2cf071.
 > Last user: [<ffffffff8032bb5f>](cfq_free_io_context+0x2f/0x74)
 > 090: d0 1a 65 3b 00 81 ff ff 6b 6b 6b 6b 6b 6b 6b 6b
 > Prev obj: start=ffff81003dcde808, len=168
 > Redzone: 0x170fc2a5/0x170fc2a5.
 > Last user: [<ffffffff8021ce1c>](cfq_set_request+0x3bb/0x41f)
 > 000: 00 00 00 00 00 00 00 00 01 00 00 00 5a 5a 5a 5a
 > 010: 00 00 00 00 00 00 00 00 08 78 44 3c 00 81 ff ff
 > Next obj: start=ffff81003dcde988, len=168
 > Redzone: 0x170fc2a5/0x170fc2a5.
 > Last user: [<ffffffff8021ce1c>](cfq_set_request+0x3bb/0x41f)
 > 000: 88 e6 cd 3d 00 81 ff ff 00 00 00 00 5a 5a 5a 5a
 > 010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 > 
 > 
 > What's interesting is the 00 81 ff ff part of the corruption
 > is there in both cases.  Anyone have any clues what this could be?

<sudden realisation> oh, it's high 32 bits of the address, duh.
Back to head-scratching.

		Dave

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