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>
diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c
index d998471..d6667c3 100644
--- a/drivers/ide/ide-cd.c
+++ b/drivers/ide/ide-cd.c
@@ -1195,6 +1195,7 @@
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 @@
*/
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 */
