Am Samstag 10 Januar 2009 schrieb Alan Cox: > > 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 ? I instrumented __atapi_pio_bytes to print some variables. This is the dump of the first two: [ 1.484730] count: 36 sg->length: 36 qc->cursg_ofs: 0 bytes: 36 [ 1.485709] qc->cdb[]:12000000240000000000000000000000 That works fine. [ 1.499843] scsi 1:0:0:0: CD-ROM HL-DT-ST DVDRAM GSA-U10N 1.05 PQ: 0 ANSI: 5 [ 1.508389] count: 18 sg->length: 96 qc->cursg_ofs: 0 bytes: 18 [ 1.509369] qc->cdb[]:03000000600000000000000000000000 That one is broken. [ 1.509369] ------------[ cut here ]------------ [ 1.509369] WARNING: at drivers/ata/libata-sff.c:1024 ata_sff_hsm_move+0x69b/0x810() -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
