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 BF9E23D5241; Fri, 24 Apr 2026 13:32:05 +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=1777037525; cv=none; b=Z7VSdZEPzJcWjrFjLSudJWUqDuLU3D4N3chAXiHmcNUR7hEHNpRaGqnkYyRsSG3wL6ks0X/qmjF5Ol02i5+KL6N0G2bBui4bqSC3xdX0hnLer2h8nBbzuGnxafrpjd3xlQAIvkraF67Qt7jg+ZsCQ252jxChlO/WVLkpX5Qiga8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777037525; c=relaxed/simple; bh=Lkf+VAwZX5TikFG2irmCaN9kQAg33GGjFkif9gmHr4s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=j8pfbS6znfHUYJf+ietIGP2I8zEpK9PFSWrVjPcjIL+AlewBvOBJyeDr8tg04zn9IyzDOAF/FYiTltpUHWe9FlJJHPBbeptC0PFY/Szcq00UX3Cd49cnZxJdRVt4Az8GbzJx69AVn60HfQ2pF8/1i0wnmEy6LyUaklU4uZeeqH8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=N3bL9hwt; 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="N3bL9hwt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 14AD7C19425; Fri, 24 Apr 2026 13:32:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1777037525; bh=Lkf+VAwZX5TikFG2irmCaN9kQAg33GGjFkif9gmHr4s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N3bL9hwtIQsRs8w/xTbKda6HMRxtQIpAhX5UxI6j4nRjP2x7FbX/522C9lucMILqn Q0Ji7sZ+y0JU0jl3OGSHu85sGx/xerCnXGv8FkEQtsTYtuv8oIooKI29XGJ0vH9YcH fx3fjiVClCMTStMS0uCzE31DPEvydf3zboWxSLnA= 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 Subject: [PATCH 7.0 12/42] f2fs: fix UAF caused by decrementing sbi->nr_pages[] in f2fs_write_end_io() Date: Fri, 24 Apr 2026 15:30:37 +0200 Message-ID: <20260424132423.010310567@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260424132420.410310336@linuxfoundation.org> References: <20260424132420.410310336@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yongpeng Yang commit 2d9c4a4ed4eef1f82c5b16b037aee8bad819fd53 upstream. 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 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 @@ -386,6 +386,8 @@ static void f2fs_write_end_io(struct bio folio->index, NODE_TYPE_REGULAR, true); f2fs_bug_on(sbi, folio->index != nid_of_node(folio)); } + if (f2fs_in_warm_node_list(sbi, folio)) + f2fs_del_fsync_node_entry(sbi, folio); dec_page_count(sbi, type); @@ -397,8 +399,6 @@ 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, folio)) - f2fs_del_fsync_node_entry(sbi, folio); folio_clear_f2fs_gcing(folio); folio_end_writeback(folio); }