[dm-devel] Re: NULL data pointer dereference in kcryptd

[Milan Broz]

Herbert Xu wrote:
> On Fri, Jul 31, 2009 at 10:54:45PM +0200, Michael Buesch wrote:
>> [15577.988608] NIP [c0000000000b8034] .mempool_alloc+0x74/0x1a0
>> [15577.988614] LR [c000000000139bdc] .bio_alloc_bioset+0x4c/0x130
>> [15577.988616] Call Trace:
>> [15577.988619] [c0000001f022fb60] [c0000001f022fbf0] 0xc0000001f022fbf0 (unreliable)
>> [15577.988625] [c0000001f022fc40] [c000000000139bdc] .bio_alloc_bioset+0x4c/0x130
>> [15577.988632] [c0000001f022fcf0] [c0000000005334a0] .kcryptd_crypt+0x210/0x520
>> [15577.988637] [c0000001f022fde0] [c000000000068018] .worker_thread+0x248/0x3e0
>> [15577.988642] [c0000001f022ff00] [c00000000006e1e4] .kthread+0x84/0xe0
>> [15577.988648] [c0000001f022ff90] [c000000000021830] .kernel_thread+0x54/0x70

That seems like mempool is NULL in bio_alloc_bioset. That mempool/bioset is destroyed only
when crypt mapping is destroyed, after workqueue is flushed, so it should not happen...

Which command did you exactly run to trigger this? only sync & mkfs on existing
LUKS device or there was also some cryptsetup luksClose (or something removing
mapping) before?

> kcryptd actually belongs to drivers/md/dm-crypt.c.  So please post
> to the DM list.

yes, this is dm-crypt or block layer problem. But I read linux-crypto list too:-)

Milan
--
mbroz at redhat.com