From patchwork Tue Sep 26 01:27:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Su Hui X-Patchwork-Id: 13398596 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C8ABE8180B for ; Tue, 26 Sep 2023 01:27:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231249AbjIZB2B (ORCPT ); Mon, 25 Sep 2023 21:28:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39340 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232218AbjIZB2A (ORCPT ); Mon, 25 Sep 2023 21:28:00 -0400 Received: from mail.nfschina.com (unknown [42.101.60.195]) by lindbergh.monkeyblade.net (Postfix) with SMTP id F3DD4101; Mon, 25 Sep 2023 18:27:52 -0700 (PDT) Received: from localhost.localdomain (unknown [180.167.10.98]) by mail.nfschina.com (Maildata Gateway V2.8.8) with ESMTPA id D75F9604DFA33; Tue, 26 Sep 2023 09:27:48 +0800 (CST) X-MD-Sfrom: suhui@nfschina.com X-MD-SrcIP: 180.167.10.98 From: Su Hui To: sfrench@samba.org, pc@manguebit.com, lsahlber@redhat.com, sprasad@microsoft.com, tom@talpey.com Cc: Su Hui , dan.carpenter@linaro.org, linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH v2] cifs: avoid possible NULL dereference Date: Tue, 26 Sep 2023 09:27:34 +0800 Message-Id: <20230926012733.814657-1-suhui@nfschina.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org smatch warn: fs/smb/client/file.c:4910 cifs_oplock_break() warn: variable dereferenced before check 'inode' (see line 4881) If 'inode' is NULL, print some warning and return. Signed-off-by: Su Hui --- fs/smb/client/file.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c index 2108b3b40ce9..de705c8b2d22 100644 --- a/fs/smb/client/file.c +++ b/fs/smb/client/file.c @@ -4878,8 +4878,8 @@ void cifs_oplock_break(struct work_struct *work) struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo, oplock_break); struct inode *inode = d_inode(cfile->dentry); - struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb); - struct cifsInodeInfo *cinode = CIFS_I(inode); + struct cifs_sb_info *cifs_sb; + struct cifsInodeInfo *cinode; struct cifs_tcon *tcon; struct TCP_Server_Info *server; struct tcon_link *tlink; @@ -4888,6 +4888,13 @@ void cifs_oplock_break(struct work_struct *work) __u64 persistent_fid, volatile_fid; __u16 net_fid; + if (!inode) { + cifs_dbg(FYI, "%s : failed to find inode\n", __func__); + return; + } + cifs_sb = CIFS_SB(inode->i_sb); + cinode = CIFS_I(inode); + wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS, TASK_UNINTERRUPTIBLE); @@ -4907,7 +4914,7 @@ void cifs_oplock_break(struct work_struct *work) cinode->oplock = 0; } - if (inode && S_ISREG(inode->i_mode)) { + if (S_ISREG(inode->i_mode)) { if (CIFS_CACHE_READ(cinode)) break_lease(inode, O_RDONLY); else