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Groups > linux.kernel > #1551375

[PATCH 4.8 01/85] aoe: fix crash in page count manipulation

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4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jens Axboe <axboe@fb.com>

commit 0cbc72a1781250f373327dd7e306e33859a42154 upstream.

aoeblk contains some mysterious code, that wants to elevate the bio
vec page counts while it's under IO. That is not needed, it's
fragile, and it's causing kernel oopses for some.

Reported-by: Tested-by: Don Koch <kochd@us.ibm.com>
Tested-by: Tested-by: Don Koch <kochd@us.ibm.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/block/aoe/aoecmd.c |   41 -----------------------------------------
 1 file changed, 41 deletions(-)

--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -853,45 +853,6 @@ rqbiocnt(struct request *r)
 	return n;
 }
 
-/* This can be removed if we are certain that no users of the block
- * layer will ever use zero-count pages in bios.  Otherwise we have to
- * protect against the put_page sometimes done by the network layer.
- *
- * See http://oss.sgi.com/archives/xfs/2007-01/msg00594.html for
- * discussion.
- *
- * We cannot use get_page in the workaround, because it insists on a
- * positive page count as a precondition.  So we use _refcount directly.
- */
-static void
-bio_pageinc(struct bio *bio)
-{
-	struct bio_vec bv;
-	struct page *page;
-	struct bvec_iter iter;
-
-	bio_for_each_segment(bv, bio, iter) {
-		/* Non-zero page count for non-head members of
-		 * compound pages is no longer allowed by the kernel.
-		 */
-		page = compound_head(bv.bv_page);
-		page_ref_inc(page);
-	}
-}
-
-static void
-bio_pagedec(struct bio *bio)
-{
-	struct page *page;
-	struct bio_vec bv;
-	struct bvec_iter iter;
-
-	bio_for_each_segment(bv, bio, iter) {
-		page = compound_head(bv.bv_page);
-		page_ref_dec(page);
-	}
-}
-
 static void
 bufinit(struct buf *buf, struct request *rq, struct bio *bio)
 {
@@ -899,7 +860,6 @@ bufinit(struct buf *buf, struct request
 	buf->rq = rq;
 	buf->bio = bio;
 	buf->iter = bio->bi_iter;
-	bio_pageinc(bio);
 }
 
 static struct buf *
@@ -1127,7 +1087,6 @@ aoe_end_buf(struct aoedev *d, struct buf
 	if (buf == d->ip.buf)
 		d->ip.buf = NULL;
 	rq = buf->rq;
-	bio_pagedec(buf->bio);
 	mempool_free(buf, d->bufpool);
 	n = (unsigned long) rq->special;
 	rq->special = (void *) --n;

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[PATCH 4.8 00/85] 4.8.16-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:10 +0100
  [PATCH 4.8 13/85] USB: cdc-acm: add device id for GW Instek AFG-125 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 27/85] clk: ti: omap36xx: Work around sprz319 advisory 2.1 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 24/85] ALSA: hda - fix headset-mic problem on a Dell laptop Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 21/85] ALSA: hiface: Fix M2Tech hiFace driver sampling rate change Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 02/85] btrfs: limit async_work allocation and worker func duration Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 33/85] Btrfs: fix memory leak in do_walk_down Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 29/85] Btrfs: bail out if block group has different mixed flag Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 28/85] Btrfs: fix memory leak in reading btree blocks Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 01/85] aoe: fix crash in page count manipulation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 15/85] usb: hub: Fix auto-remount of safely removed or ejected USB-3 devices Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 26/85] ALSA: hda: when comparing pin configurations, ignore assoc in addition to seq Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 34/85] btrfs: fix a possible umount deadlock Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 31/85] Btrfs: dont leak reloc root nodes on error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 32/85] btrfs: clean the old superblocks before freeing the device Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 18/85] USB: UHCI: report non-PME wakeup signalling for Intel hardware Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  [PATCH 4.8 11/85] USB: serial: option: add dlink dwm-158 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 22:20 +0100
  Re: [PATCH 4.8 00/85] 4.8.16-stable review Shuah Khan <shuah.kh@samsung.com> - 2017-01-05 01:50 +0100
  Re: [PATCH 4.8 00/85] 4.8.16-stable review Guenter Roeck <linux@roeck-us.net> - 2017-01-05 05:50 +0100

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