blk_rq_map_kern is used for kernel internal I/Os. Some callers use this function with stack buffers but DMA to/from the stack buffers leads to memory corruption on a non-coherent platform. This patch make blk_rq_map_kern uses the bounce buffers if a caller passes a stack buffer (on the all platforms for simplicity). Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> Cc: Jens Axboe <jens.axboe@xxxxxxxxxx> --- block/blk-map.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/block/blk-map.c b/block/blk-map.c index 0b1af5a..6b0142b 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -268,6 +268,7 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, int reading = rq_data_dir(rq) == READ; int do_copy = 0; struct bio *bio; + unsigned long stack_mask = ~(THREAD_SIZE - 1); if (len > (q->max_hw_sectors << 9)) return -EINVAL; @@ -278,6 +279,10 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, alignment = queue_dma_alignment(q) | q->dma_pad_mask; do_copy = ((kaddr & alignment) || (len & alignment)); + if (!((kaddr & stack_mask) ^ + ((unsigned long)current->stack & stack_mask))) + do_copy = 1; + if (do_copy) bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading); else -- 1.5.4.2 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
