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 A0C181A3157 for ; Fri, 24 Apr 2026 13:03:58 +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=1777035838; cv=none; b=okLYKDFEwJVtOHJXbr4BvQ+B9S63hy3DdnkdjuBVmy60EzkOihiDidavE9VP7XlCckc8ajeWhRXFwKImpEuUpe0xW5Mwitspy+vvI3c0C1dpjKKy890AYK8fnwPfz1wxA0zUTLQT97oV8k0xVObGaq2zh+HLMVGO5SpY5ozL8SA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777035838; c=relaxed/simple; bh=87vNtkDDGzXGAlaBHvugOdjDIslGu1JM6tFquA0sBIY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Q0M3vyWbIf/GRrv4KHW6JatB5PQsQqjIYAWtovk/xIeQq/6+AJB/5EvBfU8lfL80zzHzV9282zz0dFPYNGRrgpy/FMvX1xCU5Z0Y0AtypGHa+bm6Grayw0THgOPfnQxoUvX/hD226RXxnWO3DNzGXPxcCiooht7Pg9/SrKQL6rE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ePZs84a3; 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="ePZs84a3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 99480C19425; Fri, 24 Apr 2026 13:03:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777035838; bh=87vNtkDDGzXGAlaBHvugOdjDIslGu1JM6tFquA0sBIY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ePZs84a3QaAB0CQhmo70lc+BapuKiGQsNeBTvWizOj2M1uiISRGO2Ac0ZxfBavld9 fk1WH6HYB+5IV6TrCjMvUr8zfyQk7wNJTaQ8S+OP4tcnhi2t2rodPPIzMVrYOG3kwN zTmQ21Tcw1+zqhNNjgDCYoKkeJmFFaAMgkzBKIRml/z4VPvX/EWQa0YmInCRzTPMwH fxiOJ0HPFboOk5QePEHt6NehmoFCaJ6lHuUW95HIpx0GiyTNCBcSq/y6SgtVJdFiQO 4+ZQUbPrS9MDrdHHnZWBC/0lSPHKKmDtsTWBWwXOQmsM4BRqqIbJb11Jc4zmUNUQwi eJ+64otwDk60Q== From: Sasha Levin To: stable@vger.kernel.org Cc: Yongpeng Yang , stable@kernel.org, syzbot+6e4cb1cac5efc96ea0ca@syzkaller.appspotmail.com, Chao Yu , Jaegeuk Kim , Sasha Levin Subject: [PATCH 6.12.y] f2fs: fix UAF caused by decrementing sbi->nr_pages[] in f2fs_write_end_io() Date: Fri, 24 Apr 2026 09:03:55 -0400 Message-ID: <20260424130355.1917635-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026042432-donator-catalyze-5a9f@gregkh> References: <2026042432-donator-catalyze-5a9f@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- fs/f2fs/data.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 7bd6f9f108ec4..598f82386c5f0 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -355,6 +355,8 @@ static void f2fs_write_end_io(struct bio *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 *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); } -- 2.53.0