From 4c8cf6bd28d6fea23819f082ddc8063fd6fa963a Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 22 Oct 2025 10:33:31 +0200 Subject: [PATCH] block: require LBA dma_alignment when using PI The block layer PI generation / verification code expects the bio_vecs to have at least LBA size (or more correctly integrity internal) granularity. With the direct I/O alignment relaxation in 2022, user space can now feed bios with less alignment than that, leading to scribbling outside the PI buffers. Apparently this wasn't noticed so far because none of the tests generate such buffers, but since 851c4c96db00 ("xfs: implement XFS_IOC_DIOINFO in terms of vfs_getattr"), xfstests generic/013 by default generates such I/O now that the relaxed alignment is advertised by the XFS_IOC_DIOINFO ioctl. Fix this by increasing the required alignment when using PI, although handling arbitrary alignment in the long run would be even nicer. Fixes: bf8d08532bc1 ("iomap: add support for dma aligned direct-io") Fixes: b1a000d3b8ec ("block: relax direct io memory alignment") Signed-off-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Reviewed-by: Keith Busch Signed-off-by: Jens Axboe --- block/blk-settings.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/block/blk-settings.c b/block/blk-settings.c index 54cffaae4df49..d74b13ec8e548 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -184,6 +184,16 @@ static int blk_validate_integrity_limits(struct queue_limits *lim) if (!bi->interval_exp) bi->interval_exp = ilog2(lim->logical_block_size); + /* + * The PI generation / validation helpers do not expect intervals to + * straddle multiple bio_vecs. Enforce alignment so that those are + * never generated, and that each buffer is aligned as expected. + */ + if (bi->csum_type) { + lim->dma_alignment = max(lim->dma_alignment, + (1U << bi->interval_exp) - 1); + } + return 0; } -- 2.47.3