Commit 0b6abc17 authored Jul 16, 2008 by FUJITA Tomonori Committed by Bartlomiej Zolnierkiewicz Jul 16, 2008

ide: avoid DMA on the stack for REQ_TYPE_ATA_PC



Some REQ_TYPE_ATA_PC commands uses the stack buffers for DMA, which
leads to memory corruption on a non-coherent platform.

With regard to alignment and padding, ide-cd has the the dma safe
check for sg requests and REQ_TYPE_ATA_PC. This adds the stack buffer
check to that check.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Borislav Petkov <petkovbb@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

parent 84e0f3f6

drivers/ide/ide-cd.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -1195,6 +1195,7 @@ static ide_startstop_t cdrom_do_block_pc(ide_drive_t drive, struct request rq)
		int mask = drive->queue->dma_alignment;
		unsigned long addr =
		(unsigned long)page_address(bio_page(rq->bio));
		unsigned long stack_mask = ~(THREAD_SIZE - 1);

		info->dma = drive->using_dma;

		@@ -1206,6 +1207,10 @@ static ide_startstop_t cdrom_do_block_pc(ide_drive_t drive, struct request rq)
		*/
		if ((rq->data_len & 15) \|\| (addr & mask))
		info->dma = 0;

		if (!((addr & stack_mask) ^
		((unsigned long)current->stack & stack_mask)))
		info->dma = 0;
		}

		/* start sending the command to the drive */