From patchwork Thu Sep 29 22:00:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bart Van Assche X-Patchwork-Id: 610811 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 169FBC433F5 for ; Thu, 29 Sep 2022 22:00:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229864AbiI2WAf (ORCPT ); Thu, 29 Sep 2022 18:00:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229841AbiI2WAe (ORCPT ); Thu, 29 Sep 2022 18:00:34 -0400 Received: from mail-pf1-f173.google.com (mail-pf1-f173.google.com [209.85.210.173]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD336127CA1 for ; Thu, 29 Sep 2022 15:00:32 -0700 (PDT) Received: by mail-pf1-f173.google.com with SMTP id w2so2637292pfb.0 for ; Thu, 29 Sep 2022 15:00:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date; bh=O1DkugD4gXENlmzbEb7gYt3Fi1wxgizUir5A5yiHk7Y=; b=mic6a+Wbe5skutpCKjjL5gy6bLrZ8pxGXmb2tt6qwdvPPkSw1TbwnjvopEn8yUJqTQ ji2wNCbwux6+esy4SgmQ0k4ycJo3ng4c0Y7VWnipHxbl17zQ6yl/t77YuA4wCgCVGEGi zY//279xot2kVfHz2jqzfQJ6wMe8xQ7HXgIQfO4+qilKHQFJBuO5dyhqdMB5U69vxpYd EoxI79NUF96iZ2uJSCJgkrsPJEDpqFcO/IAWm0RPgRNmFdZ/uGx1ignMa4BG1V0kwU7N +XSkNueCl1aHB3bwroBG/xgCdi3GWzS2Zx3zXiXRavhJv3O/80mmTQDSiSnvIICGvvC6 wp0Q== X-Gm-Message-State: ACrzQf0gBB+go4l8Bf8lG77zs8HDh+3yyoe9Y8z3xpXdtvcMRzZDl/yV 7BTLCvTqlQTGHI8G9T+5JSw= X-Google-Smtp-Source: AMsMyM5NKjE3bUIhlGXD2N/Qq/BBfxHvzw/L7OpBIaFlZWU9JtYrWnq0ckLpQtxpaHXzrlCCckHOlg== X-Received: by 2002:a63:83c7:0:b0:440:4261:44ab with SMTP id h190-20020a6383c7000000b00440426144abmr4741165pge.266.1664488831746; Thu, 29 Sep 2022 15:00:31 -0700 (PDT) Received: from bvanassche-linux.mtv.corp.google.com ([2620:15c:211:201:56f2:482f:20c2:1d35]) by smtp.gmail.com with ESMTPSA id e3-20020a17090301c300b001782f94f8ebsm407787plh.3.2022.09.29.15.00.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Sep 2022 15:00:31 -0700 (PDT) From: Bart Van Assche To: "Martin K . Petersen" Cc: Jaegeuk Kim , linux-scsi@vger.kernel.org, Adrian Hunter , Bart Van Assche , Keith Busch , Christoph Hellwig , Ming Lei , John Garry , Mike Christie , Hannes Reinecke , "James E.J. Bottomley" , Jens Axboe Subject: [PATCH v3 1/8] scsi: core: Fix a race between scsi_done() and scsi_timeout() Date: Thu, 29 Sep 2022 15:00:14 -0700 Message-Id: <20220929220021.247097-2-bvanassche@acm.org> X-Mailer: git-send-email 2.38.0.rc1.362.ged0d419d3c-goog In-Reply-To: <20220929220021.247097-1-bvanassche@acm.org> References: <20220929220021.247097-1-bvanassche@acm.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org If there is a race between scsi_done() and scsi_timeout() and if scsi_timeout() loses the race, scsi_timeout() should not reset the request timer. Hence change the return value for this case from BLK_EH_RESET_TIMER into BLK_EH_DONE. Although the block layer holds a reference on a request (req->ref) while calling a timeout handler, restarting the timer (blk_add_timer()) while a request is being completed is racy. Cc: Keith Busch Cc: Christoph Hellwig Cc: Ming Lei Cc: John Garry Cc: Mike Christie Cc: Hannes Reinecke Reported-by: Adrian Hunter Fixes: 065990bd198e ("scsi: set timed out out mq requests to complete") Signed-off-by: Bart Van Assche Reviewed-by: Mike Christie --- drivers/scsi/scsi_error.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-) diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 16bd0adc2339..d1b07ff64a96 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -343,19 +343,11 @@ enum blk_eh_timer_return scsi_timeout(struct request *req) if (rtn == BLK_EH_DONE) { /* - * Set the command to complete first in order to prevent a real - * completion from releasing the command while error handling - * is using it. If the command was already completed, then the - * lower level driver beat the timeout handler, and it is safe - * to return without escalating error recovery. - * - * If timeout handling lost the race to a real completion, the - * block layer may ignore that due to a fake timeout injection, - * so return RESET_TIMER to allow error handling another shot - * at this command. + * If scsi_done() has already set SCMD_STATE_COMPLETE, do not + * modify *scmd. */ if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state)) - return BLK_EH_RESET_TIMER; + return BLK_EH_DONE; if (scsi_abort_command(scmd) != SUCCESS) { set_host_byte(scmd, DID_TIME_OUT); scsi_eh_scmd_add(scmd);