Re: todays git: WARNING: at drivers/ata/libata-sff.c:1017 ata_sff_hsm_move+0x45e/0x750()

Alan Cox
2009-01-10T10:41:23Z

> I did some printk debugging.
> __atapi_pio_bytes is called with bytes=18. That means with 32bit transfers
> there is a 2 byte trailing transfer, which triggers this WARN_ON.

Ouch.. that means all that someone issued a multiple segment data
transfer with a 2 byte aligned chunk in the middle.

That is a bit of a suprise because we set blk_queue_dma_alignment to 3 so
the block layer should never hand us an sg list in that form. That means
we've either got a block layer bug or someone somewhere is generating
invalid sg lists internally to libata.

Can you dump qc->cdb[] and see what command is getting issued in the
broken form ?

Alan