This is a note to let you know that I've just added the patch titled
drivers/block/brd.c: fix brd_lookup_page() race
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:
drivers-block-brd.c-fix-brd_lookup_page-race.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 <stable@xxxxxxxxxxxxxxx> know about it.
>From dfd20b2b174d3a9b258ea3b7a35ead33576587b1 Mon Sep 17 00:00:00 2001
From: Brian Behlendorf <behlendorf1@xxxxxxxx>
Date: Fri, 24 May 2013 15:55:28 -0700
Subject: drivers/block/brd.c: fix brd_lookup_page() race
From: Brian Behlendorf <behlendorf1@xxxxxxxx>
commit dfd20b2b174d3a9b258ea3b7a35ead33576587b1 upstream.
The index on the page must be set before it is inserted in the radix
tree. Otherwise there is a small race which can occur during lookup
where the page can be found with the incorrect index. This will trigger
the BUG_ON() in brd_lookup_page().
Signed-off-by: Brian Behlendorf <behlendorf1@xxxxxxxx>
Reported-by: Chris Wedgwood <cw@xxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/block/brd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -117,13 +117,13 @@ static struct page *brd_insert_page(stru
spin_lock(&brd->brd_lock);
idx = sector >> PAGE_SECTORS_SHIFT;
+ page->index = idx;
if (radix_tree_insert(&brd->brd_pages, idx, page)) {
__free_page(page);
page = radix_tree_lookup(&brd->brd_pages, idx);
BUG_ON(!page);
BUG_ON(page->index != idx);
- } else
- page->index = idx;
+ }
spin_unlock(&brd->brd_lock);
radix_tree_preload_end();
Patches currently in stable-queue which might be from behlendorf1@xxxxxxxx are
queue-3.4/drivers-block-brd.c-fix-brd_lookup_page-race.patch
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