| Message ID | 1369946097-13190-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
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();
This is a note to let you know that I have just added a patch titled drivers/block/brd.c: fix brd_lookup_page() race to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.2. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 92b12b6abad953b7882c777af51a5d5445683bc9 Mon Sep 17 00:00:00 2001 From: Brian Behlendorf <behlendorf1@llnl.gov> Date: Fri, 24 May 2013 15:55:28 -0700 Subject: drivers/block/brd.c: fix brd_lookup_page() race 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@llnl.gov> Reported-by: Chris Wedgwood <cw@f00f.org> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/block/brd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) -- 1.8.1.2