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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 885CDC282CE for ; Wed, 22 May 2019 19:52:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59D5F20856 for ; Wed, 22 May 2019 19:52:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558554740; bh=qtDvzC94e9QsmzuSJ45lCF7jx8FzTa1Ty05BUcSIs9E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lBf5U++iKi19b0oSG3+4kCwLKkLaRLlAbOT5yCRfJoEk5nHWNWhywTaOkUtOmrwdN tWDIO8fAiMbibOQ6Oeif0XvqK3fnDJp1eET4LfoPB6gqGqVJXccaPzsFLvsJwOHpFu 0oDrh40smfNuWyQorYHdSY486hWrKsZZ8/PpwEZY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731867AbfEVT0G (ORCPT ); Wed, 22 May 2019 15:26:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:47488 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731844AbfEVT0G (ORCPT ); Wed, 22 May 2019 15:26:06 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E9E7720675; Wed, 22 May 2019 19:26:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558553164; bh=qtDvzC94e9QsmzuSJ45lCF7jx8FzTa1Ty05BUcSIs9E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eq7yM0S0foQQszBXOMM0hfHk9mn/7sHDR5zsQiiz0evuLgQNuJASd22PLlg3cmrsC oDEMLXvBbQ80QWg+L5YbAA9vh+kNt0N08LW+LzLeZokSHXq5Ri8Lqy5SeCPqZUidck 9KwlXMl4pwKM6OtphgMS2y6Aipjd0ofmuHCyi/q4= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Farhan Ali , Eric Farman , Pierre Morel , Cornelia Huck , Sasha Levin , linux-s390@vger.kernel.org, kvm@vger.kernel.org Subject: [PATCH AUTOSEL 5.0 089/317] vfio-ccw: Do not call flush_workqueue while holding the spinlock Date: Wed, 22 May 2019 15:19:50 -0400 Message-Id: <20190522192338.23715-89-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190522192338.23715-1-sashal@kernel.org> References: <20190522192338.23715-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Farhan Ali [ Upstream commit cea5dde42a83b5f0a039da672f8686455936b8d8 ] Currently we call flush_workqueue while holding the subchannel spinlock. But flush_workqueue function can go to sleep, so do not call the function while holding the spinlock. Fixes the following bug: [ 285.203430] BUG: scheduling while atomic: bash/14193/0x00000002 [ 285.203434] INFO: lockdep is turned off. .... [ 285.203485] Preemption disabled at: [ 285.203488] [<000003ff80243e5c>] vfio_ccw_sch_quiesce+0xbc/0x120 [vfio_ccw] [ 285.203496] CPU: 7 PID: 14193 Comm: bash Tainted: G W .... [ 285.203504] Call Trace: [ 285.203510] ([<0000000000113772>] show_stack+0x82/0xd0) [ 285.203514] [<0000000000b7a102>] dump_stack+0x92/0xd0 [ 285.203518] [<000000000017b8be>] __schedule_bug+0xde/0xf8 [ 285.203524] [<0000000000b95b5a>] __schedule+0x7a/0xc38 [ 285.203528] [<0000000000b9678a>] schedule+0x72/0xb0 [ 285.203533] [<0000000000b9bfbc>] schedule_timeout+0x34/0x528 [ 285.203538] [<0000000000b97608>] wait_for_common+0x118/0x1b0 [ 285.203544] [<0000000000166d6a>] flush_workqueue+0x182/0x548 [ 285.203550] [<000003ff80243e6e>] vfio_ccw_sch_quiesce+0xce/0x120 [vfio_ccw] [ 285.203556] [<000003ff80245278>] vfio_ccw_mdev_reset+0x38/0x70 [vfio_ccw] [ 285.203562] [<000003ff802458b0>] vfio_ccw_mdev_remove+0x40/0x78 [vfio_ccw] [ 285.203567] [<000003ff801a499c>] mdev_device_remove_ops+0x3c/0x80 [mdev] [ 285.203573] [<000003ff801a4d5c>] mdev_device_remove+0xc4/0x130 [mdev] [ 285.203578] [<000003ff801a5074>] remove_store+0x6c/0xa8 [mdev] [ 285.203582] [<000000000046f494>] kernfs_fop_write+0x14c/0x1f8 [ 285.203588] [<00000000003c1530>] __vfs_write+0x38/0x1a8 [ 285.203593] [<00000000003c187c>] vfs_write+0xb4/0x198 [ 285.203597] [<00000000003c1af2>] ksys_write+0x5a/0xb0 [ 285.203601] [<0000000000b9e270>] system_call+0xdc/0x2d8 Signed-off-by: Farhan Ali Reviewed-by: Eric Farman Reviewed-by: Pierre Morel Message-Id: <626bab8bb2958ae132452e1ddaf1b20882ad5a9d.1554756534.git.alifm@linux.ibm.com> Signed-off-by: Cornelia Huck Signed-off-by: Sasha Levin --- drivers/s390/cio/vfio_ccw_drv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c index 0b3b9de45c602..64bb121ba5987 100644 --- a/drivers/s390/cio/vfio_ccw_drv.c +++ b/drivers/s390/cio/vfio_ccw_drv.c @@ -54,9 +54,9 @@ int vfio_ccw_sch_quiesce(struct subchannel *sch) wait_for_completion_timeout(&completion, 3*HZ); - spin_lock_irq(sch->lock); private->completion = NULL; flush_workqueue(vfio_ccw_work_q); + spin_lock_irq(sch->lock); ret = cio_cancel_halt_clear(sch, &iretry); }; -- 2.20.1