Messages in this thread Patch in this message | | | Date | Wed, 03 Jul 2013 14:39:27 -0400 | From | Steven Rostedt <> | Subject | [030/141] drivers/block/brd.c: fix brd_lookup_page() race |
| |
3.6.11.6 stable review patch. If anyone has any objections, please let me know.
------------------
From: Brian Behlendorf <behlendorf1@llnl.gov>
[ Upstream commit dfd20b2b174d3a9b258ea3b7a35ead33576587b1 ]
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@llnl.gov> Reported-by: Chris Wedgwood <cw@f00f.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- drivers/block/brd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 531ceb3..4e8213a 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -117,13 +117,13 @@ static struct page *brd_insert_page(struct brd_device *brd, sector_t sector) 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(); -- 1.7.10.4
| |