Messages in this thread | | | Date | Fri, 27 Aug 2010 17:38:01 +0800 | From | liubo <> | Subject | Re: [2.6.35.3] BUG: unable to handle kernel NULL pointer dereference at (null) |
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On 08/26/2010 05:53 PM, Carlos R. Mafra wrote: > Hi, > > I've just got this BUG: message in dmesg which I think is btrfs related. > [...]
> [ 148.152107] Call Trace: > [ 148.152113] [<ffffffff8104e730>] ? process_timeout+0x0/0x10 > [ 148.152118] [<ffffffff8118a42d>] end_workqueue_fn+0x10d/0x130 > [ 148.152122] [<ffffffff811b98f0>] worker_loop+0xb0/0x5a0 > [ 148.152126] [<ffffffff811b9840>] ? worker_loop+0x0/0x5a0 > [ 148.152130] [<ffffffff8105b60e>] kthread+0x8e/0xa0 > [ 148.152135] [<ffffffff81003a54>] kernel_thread_helper+0x4/0x10 > [ 148.152138] [<ffffffff8105b580>] ? kthread+0x0/0xa0 > [ 148.152142] [<ffffffff81003a50>] ? kernel_thread_helper+0x0/0x10 > [ 148.152144] Code: d3 ff ff 89 c2 b8 01 00 00 00 85 d2 75 56 4c 39 eb 77 51 0f 1f 80 00 00 00 00 48 89 de 49 8b 7c 24 10 48 c1 ee 0c e8 3f 21 ef ff <f6> 00 08 74 2a 48 89 c7 48 81 c3 00 10 00 00 e8 4b af ef ff 49 > [ 148.152176] RIP [<ffffffff811b1301>] extent_range_uptodate+0x51/0xa0 > [ 148.152180] RSP <ffff880079acddd0> > [ 148.152182] CR2: 0000000000000000 > [ 148.152185] ---[ end trace c11a5009b12451d7 ]--- > >
Hi, Carlos, Did you hit this bug under heavy memory stress?
And, could you reproduce the bug? or show some reproduce steps for us?
After digging into extent_range_uptodate(), IMO, this NULL pointer bug that issued page can barely be hit.
Maybe, due to heavy memory stress, a page of the extent_buffer has been freed before, which leads that it is missing in page_cache and return NULL.
thanks, liubo
> Full dmesg is here > > http://www.aei.mpg.de/~crmafra/dmesg-2.6.35.3.txt > > Is there something else I should provide to help debug this? > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > > >
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