From mboxrd@z Thu Jan 1 00:00:00 1970 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 465FE3E3D8F; Mon, 4 May 2026 14:27:51 +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=1777904871; cv=none; b=RzwJg15qgP5n0mupcNWKPNGdyshH6mlzYRijG//XldrcA4LRduT70jlcJY4bkaqe94CY1dEGGaQVi5hJjsD/V459NyCJ6cw5Bg1y9/Ro/HFo5DEXkt5bwWkaRr5ZPZ2UFyb1y7XPTLmkmhQ5yecfDqcmvUYkgUKDVJi4uF939fk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777904871; c=relaxed/simple; bh=kPoDmjoyScaVAYznQs9yrP7VRiOZdZ29AMH5AJaL/yI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GR2+Z6SuZ23Fk9KYbYg0t0j/W1R9hZLIdjZJK9uU4/aJprQhcqyjQRq6Jo+5awVA+K6GovAc55ekOQZeF8jdEQZNAUJ3VMuSmh0pKLxHAN+ypZrmzYTC4qwjp3VH+9aneYCP6rOIqrxcRlgesP2opfzKeOli9EdLQhXbKTLmIyw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DQY14o+x; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="DQY14o+x" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3E88C2BCB8; Mon, 4 May 2026 14:27:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1777904871; bh=kPoDmjoyScaVAYznQs9yrP7VRiOZdZ29AMH5AJaL/yI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DQY14o+xqnF0cig6hstoyFhv2zDVzetWfDXOTkDFOYyQfO+P3nezVcmmZLlzejvnE DVuM01j7g7rCnqEdD8V8gCwGfYLNxSiQDo6Mm3u+9eo9GY2bWgY0nT2LlXUAqX3IiK LRfF2I1YYRIW2Wh9bfM1VaVaO6F3TBon7xwlLWUo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, syzbot+6e4cb1cac5efc96ea0ca@syzkaller.appspotmail.com, Yongpeng Yang , Chao Yu , Jaegeuk Kim , Sasha Levin Subject: [PATCH 6.12 174/215] f2fs: fix UAF caused by decrementing sbi->nr_pages[] in f2fs_write_end_io() Date: Mon, 4 May 2026 15:53:13 +0200 Message-ID: <20260504135136.551763603@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260504135130.169210693@linuxfoundation.org> References: <20260504135130.169210693@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yongpeng Yang [ Upstream commit 2d9c4a4ed4eef1f82c5b16b037aee8bad819fd53 ] The xfstests case "generic/107" and syzbot have both reported a NULL pointer dereference. The concurrent scenario that triggers the panic is as follows: F2FS_WB_CP_DATA write callback umount - f2fs_write_checkpoint - f2fs_wait_on_all_pages(sbi, F2FS_WB_CP_DATA) - blk_mq_end_request - bio_endio - f2fs_write_end_io : dec_page_count(sbi, F2FS_WB_CP_DATA) : wake_up(&sbi->cp_wait) - kill_f2fs_super - kill_block_super - f2fs_put_super : iput(sbi->node_inode) : sbi->node_inode = NULL : f2fs_in_warm_node_list - is_node_folio // sbi->node_inode is NULL and panic The root cause is that f2fs_put_super() calls iput(sbi->node_inode) and sets sbi->node_inode to NULL after sbi->nr_pages[F2FS_WB_CP_DATA] is decremented to zero. As a result, f2fs_in_warm_node_list() may dereference a NULL node_inode when checking whether a folio belongs to the node inode, leading to a panic. This patch fixes the issue by calling f2fs_in_warm_node_list() before decrementing sbi->nr_pages[F2FS_WB_CP_DATA], thus preventing the use-after-free condition. Cc: stable@kernel.org Fixes: 50fa53eccf9f ("f2fs: fix to avoid broken of dnode block list") Reported-by: syzbot+6e4cb1cac5efc96ea0ca@syzkaller.appspotmail.com Signed-off-by: Yongpeng Yang Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim [ folio => page ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/f2fs/data.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -355,6 +355,8 @@ static void f2fs_write_end_io(struct bio f2fs_bug_on(sbi, page->mapping == NODE_MAPPING(sbi) && page_folio(page)->index != nid_of_node(page)); + if (f2fs_in_warm_node_list(sbi, page)) + f2fs_del_fsync_node_entry(sbi, page); dec_page_count(sbi, type); @@ -366,8 +368,6 @@ static void f2fs_write_end_io(struct bio wq_has_sleeper(&sbi->cp_wait)) wake_up(&sbi->cp_wait); - if (f2fs_in_warm_node_list(sbi, page)) - f2fs_del_fsync_node_entry(sbi, page); clear_page_private_gcing(page); end_page_writeback(page); }