From patchwork Sun Feb 16 13:16:03 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Filipe Manana X-Patchwork-Id: 13976543 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 774701922E1 for ; Sun, 16 Feb 2025 13:16:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739711771; cv=none; b=ibervbE8k3m3ba6xidFIuPJXZIKS0IYgfORtnMGjzUhvH/2/YMzmSxVNjvKeQjWFDvv+w+ikArcqz1aw+jozaw5YXNfXCc4/kjOCOyM1LA0zosc37Sf0PU3W1+C2w6BlJe+5JfDHf45CPbgC9jfFQUpLUgE/Lc0lK4rtpUnVEBg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739711771; c=relaxed/simple; bh=QfHeRz8iwer6p2OtaUFeKxKIiN2+3pQ3ywUXi2DoRLE=; h=From:To:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=L6SUuCGwyzDMkOsMaQDtk+d0yYZrn0zSqBl/gBzOtZHJId739YYTSr/O2Dd+puzAFkVZJZLAfPiL1LPeFU+jgXTwgUGVS8sXfN9wDqGo5GWnr53qqrhTeCJF7H6viYcP1khhas/IYCj1fQ+7w9nWOV4eQqFLDSGK+lbN8ezOcFY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DyLOMPb1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="DyLOMPb1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6FE43C4CEE2 for ; Sun, 16 Feb 2025 13:16:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739711770; bh=QfHeRz8iwer6p2OtaUFeKxKIiN2+3pQ3ywUXi2DoRLE=; h=From:To:Subject:Date:In-Reply-To:References:From; b=DyLOMPb1HtvF6wAPiWOpMZa0gsrOa7Oa10+oV5hHNLuPeQIJ6LPv+YMuvFCl698ti TpByok6ST6irRsjQFlCM9tUK2q6ydGHo1QjnqAUCw8fmyJk/Tas59GEETxF+n6zlwo BgWGQKFslX0mTBw9K61IjnC30ju6WxLtQf6Yn3U2gVjQVlfMnGrwWYvtz00Nhbc2ae PPvEPjmhmYa4RMl95sd70M2Xlo8kRM0tOKW4gnNi5fa27L1sYKzn1pPUVkP6g2qhOD FkhmlSefYvR1U7rfzUNGYsheCbzbUkLRHiO3ZREZrL3TqkNmvAP2tf32CZUynNOYIJ sK7PfQvxNnfCw== From: fdmanana@kernel.org To: linux-btrfs@vger.kernel.org Subject: [PATCH 1/3] btrfs: fix use-after-free on inode when scanning root during em shrinking Date: Sun, 16 Feb 2025 13:16:03 +0000 Message-Id: <38c908d189e4bd6c5d137c20d9fb905509625069.1739710434.git.fdmanana@suse.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Filipe Manana At btrfs_scan_root() we are accessing the inode's root (and fs_info) in a call to btrfs_fs_closing() after we have scheduled the inode for a delayed iput, and that can result in a use-after-free on the inode in case the cleaner kthread does the iput before we dereference the inode in the call to btrfs_fs_closing(). Fix this by using the fs_info stored already in a local variable instead of doing inode->root->fs_info. Fixes: 102044384056 ("btrfs: make the extent map shrinker run asynchronously as a work queue job") CC: stable@vger.kernel.org # 6.13+ Tested-by: Ivan Shapovalov Link: https://lore.kernel.org/linux-btrfs/0414d690ac5680d0d77dfc930606cdc36e42e12f.camel@intelfx.name/ Signed-off-by: Filipe Manana Reviewed-by: Johannes Thumshirn --- fs/btrfs/extent_map.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index 67ce85ff0ae2..bee1b94a1049 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -1222,8 +1222,7 @@ static long btrfs_scan_root(struct btrfs_root *root, struct btrfs_em_shrink_ctx fs_info->em_shrinker_last_ino = btrfs_ino(inode); btrfs_add_delayed_iput(inode); - if (ctx->scanned >= ctx->nr_to_scan || - btrfs_fs_closing(inode->root->fs_info)) + if (ctx->scanned >= ctx->nr_to_scan || btrfs_fs_closing(fs_info)) break; cond_resched();