From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 5D2913C3C1E; Tue, 16 Jun 2026 17:47:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781632038; cv=none; b=PNt9xCHbnQYwqNPLE0Fy7Zwecm0ttWCvD0P4ksmg2xODfNKeiEb/wrFRV1+oF3tmHIZzK4PaeUqXwTr5hCdIPpeSyQdx2icGHN3VkFgWHX2r6g1ORTQ/eFE7s5RTq8G8f1ETD2gh2pYCaHLrPrzzPWhDP1h+ZzkdFAV/lbKrpMQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781632038; c=relaxed/simple; bh=yXV0XpI5k1lCRVi8kpJ5fbhQBQPD1Qbhu5fkOkDdKFw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rWxe9MGR1LspH1MQMFRJhiJExOXwMLIgu9eYxeiBXhgpX4neFNNEqfDpLTSOzwvH0ofAwcDfxaEyve4YjzoFRfAK6EG02ZTAFaDW7L7doeRT6pERPemX6af1i1hhqjXUcjlySjZyzLSQjePnHmam1lCw126Ripvi0w5Os/bESXI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qffuAUoe; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qffuAUoe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA30C1F000E9; Tue, 16 Jun 2026 17:47:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781632037; bh=Bc9VIHypQCVnTkMeCPfjqC9ImRjxWPoKKQUZ/bnV0zc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=qffuAUoeJx6cN0xG0z64Xx0bf1a2pnfoUvklf10gAtFWKzXQBFn2fkD37Kwu2zTX2 MyQl7paP56w01Db/7hjBmNCe8jagRxyJ4ORApSQZtBXVXpo5Qc5HxIFvbUmV/yxgzJ eNXsBdSMM3/7nNtiT4MYty5VQ/5+BngLzQulTIgo= 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 6.1 333/522] f2fs: fix UAF caused by decrementing sbi->nr_pages[] in f2fs_write_end_io() Date: Tue, 16 Jun 2026 20:28:00 +0530 Message-ID: <20260616145141.403297957@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145125.307082728@linuxfoundation.org> References: <20260616145125.307082728@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 6.1-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 @@ -356,6 +356,8 @@ static void f2fs_write_end_io(struct bio f2fs_bug_on(sbi, page->mapping == NODE_MAPPING(sbi) && 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); @@ -367,8 +369,6 @@ 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); }