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=-19.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 95A92C4320A for ; Tue, 10 Aug 2021 14:21:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7E6B060EBB for ; Tue, 10 Aug 2021 14:21:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239155AbhHJOWM (ORCPT ); Tue, 10 Aug 2021 10:22:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:54320 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242450AbhHJORl (ORCPT ); Tue, 10 Aug 2021 10:17:41 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0025B60FC4; Tue, 10 Aug 2021 14:16:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1628604993; bh=giHaAstC8Bh46xIwh8NrBSVBtLrPa6XnDBRZqx876pc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=H472t2iLz06im9VSAqtAJ4G1GAMZ+y4esDNZSg6uDJN6bEIiX938qcxD23HCLcnhZ jmAfrqpuRtYB73aBtlCqFzEnvEeIYrDCRBHJCcMnFHSM7IU/7nBSQhbeaiUepuOT93 c4ORCeHf703b8FN0UAgjH4xMzZVTz66ur7QJRaIrX2KSYNi+dXrGDJ3TtTBEz03d3F hdYkcJymBXqsLdaALEP2RTutXoeT4+AHp5DR2EkADHibnG3AKohgXFP3kiJlCripON BCfvc0j2jsxddeyrsNbSWrZ7k7wEDK2oYjiqlN3g8i3nHFszC/gaQyFvcYJeVmCMld 7GXue/7QRCY9Q== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ye Bin , Bart Van Assche , "Martin K . Petersen" , Sasha Levin , linux-scsi@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 06/11] scsi: scsi_dh_rdac: Avoid crash during rdac_bus_attach() Date: Tue, 10 Aug 2021 10:16:19 -0400 Message-Id: <20210810141625.3118097-6-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210810141625.3118097-1-sashal@kernel.org> References: <20210810141625.3118097-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ye Bin [ Upstream commit bc546c0c9abb3bb2fb46866b3d1e6ade9695a5f6 ] The following BUG_ON() was observed during RDAC scan: [595952.944297] kernel BUG at drivers/scsi/device_handler/scsi_dh_rdac.c:427! [595952.951143] Internal error: Oops - BUG: 0 [#1] SMP ...... [595953.251065] Call trace: [595953.259054] check_ownership+0xb0/0x118 [595953.269794] rdac_bus_attach+0x1f0/0x4b0 [595953.273787] scsi_dh_handler_attach+0x3c/0xe8 [595953.278211] scsi_dh_add_device+0xc4/0xe8 [595953.282291] scsi_sysfs_add_sdev+0x8c/0x2a8 [595953.286544] scsi_probe_and_add_lun+0x9fc/0xd00 [595953.291142] __scsi_scan_target+0x598/0x630 [595953.295395] scsi_scan_target+0x120/0x130 [595953.299481] fc_user_scan+0x1a0/0x1c0 [scsi_transport_fc] [595953.304944] store_scan+0xb0/0x108 [595953.308420] dev_attr_store+0x44/0x60 [595953.312160] sysfs_kf_write+0x58/0x80 [595953.315893] kernfs_fop_write+0xe8/0x1f0 [595953.319888] __vfs_write+0x60/0x190 [595953.323448] vfs_write+0xac/0x1c0 [595953.326836] ksys_write+0x74/0xf0 [595953.330221] __arm64_sys_write+0x24/0x30 Code is in check_ownership: list_for_each_entry_rcu(tmp, &h->ctlr->dh_list, node) { /* h->sdev should always be valid */ BUG_ON(!tmp->sdev); tmp->sdev->access_state = access_state; } rdac_bus_attach initialize_controller list_add_rcu(&h->node, &h->ctlr->dh_list); h->sdev = sdev; rdac_bus_detach list_del_rcu(&h->node); h->sdev = NULL; Fix the race between rdac_bus_attach() and rdac_bus_detach() where h->sdev is NULL when processing the RDAC attach. Link: https://lore.kernel.org/r/20210113063103.2698953-1-yebin10@huawei.com Reviewed-by: Bart Van Assche Signed-off-by: Ye Bin Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/scsi/device_handler/scsi_dh_rdac.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c index 6c629ef1bc4e..b3c23edd4b6c 100644 --- a/drivers/scsi/device_handler/scsi_dh_rdac.c +++ b/drivers/scsi/device_handler/scsi_dh_rdac.c @@ -453,8 +453,8 @@ static int initialize_controller(struct scsi_device *sdev, if (!h->ctlr) err = SCSI_DH_RES_TEMP_UNAVAIL; else { - list_add_rcu(&h->node, &h->ctlr->dh_list); h->sdev = sdev; + list_add_rcu(&h->node, &h->ctlr->dh_list); } spin_unlock(&list_lock); err = SCSI_DH_OK; @@ -779,11 +779,11 @@ static void rdac_bus_detach( struct scsi_device *sdev ) spin_lock(&list_lock); if (h->ctlr) { list_del_rcu(&h->node); - h->sdev = NULL; kref_put(&h->ctlr->kref, release_controller); } spin_unlock(&list_lock); sdev->handler_data = NULL; + synchronize_rcu(); kfree(h); } -- 2.30.2