On Mon, Mar 13, 2017 at 07:06:01PM +0200, Krzysztof Kozlowski wrote: > > I bisected this to commit f1c131b45410 ("crypto: xts - Convert to > skcipher"). The s5p-sss driver stays the same... but the xts changes and > as a result we have a NULL pointer dereference (actually of value > 00000004): > [ 18.930195] Unable to handle kernel NULL pointer dereference at virtual address 00000004 > ... > [ 18.972325] [<c0313c98>] (post_crypt) from [<c031408c>] (decrypt_done+0x4c/0x54) > [ 18.972343] [<c031408c>] (decrypt_done) from [<c056309c>] (s5p_aes_interrupt+0x1bc/0x208) > [ 18.972360] [<c056309c>] (s5p_aes_interrupt) from [<c0164930>] (irq_thread_fn+0x1c/0x54) > > Any hints? I haven't found any smoking guns, but the locking between the tasklet and the IRQ routine looks suspect. First of all the tasklet is modifying the dev structure without holding any locks. More importantly, the IRQ routine does not seem to be robust in the face of spurious interrupts. Should a spurious interrupt arrive, it is entirely possible for the tasklet's modifying of dev->req to race with the IRQ routine which reads dev->req. However, this does depend on there being a spurious interrupt so I don't know how likely it is. Anyway, if we can't get to the bottom of this, we should disable the broken functionality. Cheers, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt