mbox series

[V3,0/2] block: fix page leak by merging to same page

Message ID 20190610090215.14412-1-ming.lei@redhat.com (mailing list archive)
Headers show
Series block: fix page leak by merging to same page | expand

Message

Ming Lei June 10, 2019, 9:02 a.m. UTC 
Hi,

'pages' retrived by __bio_iov_iter_get_pages() may point to same page,
and finally they can be merged to the same page in bio_add_page(), then
page leak can be caused because bio_release_pages() only drops the page
ref once.

Fixes this issue by dropping the extra page ref.

V3:
	- avoid to call __bio_try_merge_page() two times
	- add comment on the two new flags

V2:
	- V1 breaks multi-page merge, and fix it and only put the page ref
	if the added page is really the 'same page' 


Ming Lei (2):
  block: introduce 'enum bvec_merge_flags' for __bio_try_merge_page
  block: fix page leak in case of merging to same page

 block/bio.c         | 32 ++++++++++++++++++++++----------
 fs/iomap.c          |  3 ++-
 fs/xfs/xfs_aops.c   |  3 ++-
 include/linux/bio.h | 22 +++++++++++++++++++++-
 4 files changed, 47 insertions(+), 13 deletions(-)

Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: linux-xfs@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>