Messages in this thread Patch in this message | | | Date | Tue, 21 Mar 2006 10:38:30 +0200 | From | Dan Aloni <> | Subject | [PATCH] scsi: properly count the number of pages in scsi_req_map_sg() |
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Improper calculation of the number of pages causes bio_alloc() to be called with nr_iovecs=0, and slab corruption later.
For example, a simple scatterlist that fails: {(3644,452), (0, 60)}, (offset, size). bufflen=512 => nr_pages=1 => breakage. The proper page count for this example is 2.
Signed-off-by: Dan Aloni <da-x@monatomic.org>
--- commit 8faa94b01e6fd4518b760ce39a2db0ede9444ded tree c2e3c6ee5f59a4c1e166e4798ddc6e938f448de2 parent c4a1745aa09fc110afdefea0e5d025043e348bae author Dan Aloni <da-x@monatomic.org> Tue, 21 Mar 2006 10:19:11 +0200 committer Dan Aloni <da-x@monatomic.org> Tue, 21 Mar 2006 10:19:11 +0200
drivers/scsi/scsi_lib.c | 9 ++++++++- 1 files changed, 8 insertions(+), 1 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 701a328..a42f3aa 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -368,13 +368,20 @@ static int scsi_req_map_sg(struct reques int nsegs, unsigned bufflen, gfp_t gfp) { struct request_queue *q = rq->q; - int nr_pages = (bufflen + PAGE_SIZE - 1) >> PAGE_SHIFT; + int nr_pages = 0; unsigned int data_len = 0, len, bytes, off; struct page *page; struct bio *bio = NULL; int i, err, nr_vecs = 0; for (i = 0; i < nsegs; i++) { + off = sgl[i].offset; + len = sgl[i].length; + + nr_pages += ((off + len + PAGE_SIZE - 1) >> PAGE_SHIFT) - (off >> PAGE_SHIFT); + } + + for (i = 0; i < nsegs; i++) { page = sgl[i].page; off = sgl[i].offset; len = sgl[i].length;
-- Dan Aloni da-x@monatomic.org, da-x@colinux.org, da-x@gmx.net, dan@xiv.co.il - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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