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 <[email protected]>
---
commit 8faa94b01e6fd4518b760ce39a2db0ede9444ded
tree c2e3c6ee5f59a4c1e166e4798ddc6e938f448de2
parent c4a1745aa09fc110afdefea0e5d025043e348bae
author Dan Aloni <[email protected]> Tue, 21 Mar 2006 10:19:11 +0200
committer Dan Aloni <[email protected]> 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
[email protected], [email protected], [email protected], [email protected]
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
