From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5759FCA9EAF for ; Sun, 27 Oct 2019 21:11:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1FAF1214AF for ; Sun, 27 Oct 2019 21:11:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572210666; bh=t/wq/WZPF0b75fqr10+zFJOVGpK2Dc4F7FNpxG8v3bI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Jp7Xm1Zh5hdPKZmumyLeaz1ApcCHVnjKKXQgMkdS8twngTgIOZSydSMcOozy/v9Sd t4fvzHILKioicqHcbj5GDrOLW4VRMes3qaW7auwA9ZvqFKP6vjpu+Em64qNA2weeJg HT2jO8rx4a+mjHtVsstw+tN12uF0OeD8E1VPuxnk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729828AbfJ0VLF (ORCPT ); Sun, 27 Oct 2019 17:11:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:57490 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729814AbfJ0VLA (ORCPT ); Sun, 27 Oct 2019 17:11:00 -0400 Received: from localhost (100.50.158.77.rev.sfr.net [77.158.50.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4C589214E0; Sun, 27 Oct 2019 21:10:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572210659; bh=t/wq/WZPF0b75fqr10+zFJOVGpK2Dc4F7FNpxG8v3bI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bzxS1LnUIxdoIRZqfIfuJZoCSf8mABIKElKH8qZUuZeyTzLEmyfgaMq3YWpMTTHs5 NC4rVFgqakg8/PMunHbBIvdP4N8VGX54X/qVFso5KoerIfWGh4PpP7+XxcfOMOCd82 fahNf43fgEnXTPd+WDbmaQkg+CxnbZwXDEp998VI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hannes Reinecke , Rob Turk , Bart Van Assche , "Martin K. Petersen" Subject: [PATCH 4.14 090/119] scsi: ch: Make it possible to open a ch device multiple times again Date: Sun, 27 Oct 2019 22:01:07 +0100 Message-Id: <20191027203348.205230988@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191027203259.948006506@linuxfoundation.org> References: <20191027203259.948006506@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bart Van Assche commit 6a0990eaa768dfb7064f06777743acc6d392084b upstream. Clearing ch->device in ch_release() is wrong because that pointer must remain valid until ch_remove() is called. This patch fixes the following crash the second time a ch device is opened: BUG: kernel NULL pointer dereference, address: 0000000000000790 RIP: 0010:scsi_device_get+0x5/0x60 Call Trace: ch_open+0x4c/0xa0 [ch] chrdev_open+0xa2/0x1c0 do_dentry_open+0x13a/0x380 path_openat+0x591/0x1470 do_filp_open+0x91/0x100 do_sys_open+0x184/0x220 do_syscall_64+0x5f/0x1a0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: 085e56766f74 ("scsi: ch: add refcounting") Cc: Hannes Reinecke Cc: Link: https://lore.kernel.org/r/20191009173536.247889-1-bvanassche@acm.org Reported-by: Rob Turk Suggested-by: Rob Turk Signed-off-by: Bart Van Assche Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/ch.c | 1 - 1 file changed, 1 deletion(-) --- a/drivers/scsi/ch.c +++ b/drivers/scsi/ch.c @@ -578,7 +578,6 @@ ch_release(struct inode *inode, struct f scsi_changer *ch = file->private_data; scsi_device_put(ch->device); - ch->device = NULL; file->private_data = NULL; kref_put(&ch->ref, ch_destroy); return 0;