Messages in this thread | | | Date | Fri, 27 Aug 2010 20:03:01 +0200 | From | "Carlos R. Mafra" <> | Subject | Re: [2.6.35.3] BUG: unable to handle kernel NULL pointer dereference at (null) |
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On Fr 27.Aug'10 at 17:38:01 +0800, liubo wrote: > 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?
Not at all!
My laptop had been recently booted (see the timings in the dmesg) and it was basically idle: just a couple xterms and WindowMaker running, apart from the chromium which I tried to open and led to the bug.
> And, could you reproduce the bug? or show some reproduce steps for us?
Unfortunately not. That was the first time, and it didn't repeat so far.
> 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.
Could it be that the memory card had some bad block and btrfs could not recover from the failure?
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