This is a note to let you know that I've just added the patch titled
ceph: check PG_Private flag before accessing page->private
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
0037-ceph-check-PG_Private-flag-before-accessing-page-pri.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From f0be86dddb0ce060e6ea0b747206b807d446b51f Mon Sep 17 00:00:00 2001
From: "Yan, Zheng" <[email protected]>
Date: Mon, 28 May 2012 14:44:30 +0800
Subject: ceph: check PG_Private flag before accessing page->private
From: "Yan, Zheng" <[email protected]>
(cherry picked from commit 28c0254ede13ab575d2df5c6585ed3d4817c3e6b)
I got lots of NULL pointer dereference Oops when compiling kernel on ceph.
The bug is because the kernel page migration routine replaces some pages
in the page cache with new pages, these new pages' private can be non-zero.
Signed-off-by: Zheng Yan <[email protected]>
Signed-off-by: Sage Weil <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/ceph/addr.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -54,7 +54,12 @@
(CONGESTION_ON_THRESH(congestion_kb) - \
(CONGESTION_ON_THRESH(congestion_kb) >> 2))
-
+static inline struct ceph_snap_context *page_snap_context(struct page *page)
+{
+ if (PagePrivate(page))
+ return (void *)page->private;
+ return NULL;
+}
/*
* Dirty a page. Optimistically adjust accounting, on the assumption
@@ -142,10 +147,9 @@ static void ceph_invalidatepage(struct p
{
struct inode *inode;
struct ceph_inode_info *ci;
- struct ceph_snap_context *snapc = (void *)page->private;
+ struct ceph_snap_context *snapc = page_snap_context(page);
BUG_ON(!PageLocked(page));
- BUG_ON(!page->private);
BUG_ON(!PagePrivate(page));
BUG_ON(!page->mapping);
@@ -182,7 +186,6 @@ static int ceph_releasepage(struct page
struct inode *inode = page->mapping ? page->mapping->host : NULL;
dout("%p releasepage %p idx %lu\n", inode, page, page->index);
WARN_ON(PageDirty(page));
- WARN_ON(page->private);
WARN_ON(PagePrivate(page));
return 0;
}
@@ -443,7 +446,7 @@ static int writepage_nounlock(struct pag
osdc = &fsc->client->osdc;
/* verify this is a writeable snap context */
- snapc = (void *)page->private;
+ snapc = page_snap_context(page);
if (snapc == NULL) {
dout("writepage %p page %p not dirty?\n", inode, page);
goto out;
@@ -451,7 +454,7 @@ static int writepage_nounlock(struct pag
oldest = get_oldest_context(inode, &snap_size);
if (snapc->seq > oldest->seq) {
dout("writepage %p page %p snapc %p not writeable - noop\n",
- inode, page, (void *)page->private);
+ inode, page, snapc);
/* we should only noop if called by kswapd */
WARN_ON((current->flags & PF_MEMALLOC) == 0);
ceph_put_snap_context(oldest);
@@ -591,7 +594,7 @@ static void writepages_finish(struct cep
clear_bdi_congested(&fsc->backing_dev_info,
BLK_RW_ASYNC);
- ceph_put_snap_context((void *)page->private);
+ ceph_put_snap_context(page_snap_context(page));
page->private = 0;
ClearPagePrivate(page);
dout("unlocking %d %p\n", i, page);
@@ -795,7 +798,7 @@ get_more_pages:
}
/* only if matching snap context */
- pgsnapc = (void *)page->private;
+ pgsnapc = page_snap_context(page);
if (pgsnapc->seq > snapc->seq) {
dout("page snapc %p %lld > oldest %p %lld\n",
pgsnapc, pgsnapc->seq, snapc, snapc->seq);
@@ -984,7 +987,7 @@ retry_locked:
BUG_ON(!ci->i_snap_realm);
down_read(&mdsc->snap_rwsem);
BUG_ON(!ci->i_snap_realm->cached_context);
- snapc = (void *)page->private;
+ snapc = page_snap_context(page);
if (snapc && snapc != ci->i_head_snapc) {
/*
* this page is already dirty in another (older) snap
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/0036-rbd-Fix-ceph_snap_context-size-calculation.patch
queue-3.4/0030-rbd-Clear-ceph_msg-bio_iter-for-retransmitted-messag.patch
queue-3.4/0037-ceph-check-PG_Private-flag-before-accessing-page-pri.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
