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 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3CAB7C77B7A for ; Wed, 7 Jun 2023 13:57:53 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 11FC210E4F0; Wed, 7 Jun 2023 13:57:51 +0000 (UTC) Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by gabe.freedesktop.org (Postfix) with ESMTPS id E8CA410E4E4; Wed, 7 Jun 2023 13:57:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1686146268; x=1717682268; h=message-id:date:mime-version:subject:to:references:from: in-reply-to:content-transfer-encoding; bh=DNe5fS5WuKfbKBZJ1ksfduMTgwuqBmlrRmIBZCdeE0Q=; b=Z9mjO0KH0deQnM3tVSarhOBJPWkI69mvQ1110rAoQNzczEljwyPpfpGd 00kLUStp+s9EmJqUVGl3ZNfcAiUqBcREoB9Egm4TQbF8MfcUkwmi628A6 jMp+TlqGgPeU50zpn10dciLZNEVF0yiQ25r39i4XqJ+OW3Xs1M16hPWjA bTRDo1Zrw8D+169G39N8b4r+JD4TnJZ/JMbE/BLKlAl1xYxBgAXiGSlIi RElknhVtCsdgONfOpODNv24EGd65NInvNOdQmxatQT5NyJBSnYXbkNyYh KDdqmclmZZhkij2LAg6NNtCGjp6UAdyYYK3hMZiHqIriI0HWvGpWF/Iqv w==; X-IronPort-AV: E=McAfee;i="6600,9927,10734"; a="336619590" X-IronPort-AV: E=Sophos;i="6.00,224,1681196400"; d="scan'208";a="336619590" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jun 2023 06:57:46 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10734"; a="739277084" X-IronPort-AV: E=Sophos;i="6.00,224,1681196400"; d="scan'208";a="739277084" Received: from ahajda-mobl.ger.corp.intel.com (HELO [10.213.20.254]) ([10.213.20.254]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jun 2023 06:57:45 -0700 Message-ID: <3ea4aefb-3ea5-e565-1b58-455d564264f0@intel.com> Date: Wed, 7 Jun 2023 15:57:43 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.11.2 Content-Language: en-US To: Zhanjun Dong , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org References: <20230606030037.196558-1-zhanjun.dong@intel.com> From: Andrzej Hajda Organization: Intel Technology Poland sp. z o.o. - ul. Slowackiego 173, 80-298 Gdansk - KRS 101882 - NIP 957-07-52-316 In-Reply-To: <20230606030037.196558-1-zhanjun.dong@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Intel-gfx] [PATCH] drm/i915: Avoid circular locking dependency when flush delayed work on gt reset X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On 06.06.2023 05:00, Zhanjun Dong wrote: > This attemps to avoid circular locing dependency between flush delayed work and intel_gt_reset. > > WARNING: possible circular locking dependency detected > 6.4.0-rc1-drmtip_1340-g31e3463b0edb+ #1 Not tainted > ------------------------------------------------------ > kms_pipe_crc_ba/6415 is trying to acquire lock: > ffff88813e6cc640 ((work_completion)(&(&guc->timestamp.work)->work)){+.+.}-{0:0}, at: __flush_work+0x42/0x530 > > but task is already holding lock: > ffff88813e6cce90 (>->reset.mutex){+.+.}-{3:3}, at: intel_gt_reset+0x19e/0x470 [i915] > > which lock already depends on the new lock. > > the existing dependency chain (in reverse order) is: > > -> #3 (>->reset.mutex){+.+.}-{3:3}: > lock_acquire+0xd8/0x2d0 > i915_gem_shrinker_taints_mutex+0x31/0x50 [i915] > intel_gt_init_reset+0x65/0x80 [i915] > intel_gt_common_init_early+0xe1/0x170 [i915] > intel_root_gt_init_early+0x48/0x60 [i915] > i915_driver_probe+0x671/0xcb0 [i915] > i915_pci_probe+0xdc/0x210 [i915] > pci_device_probe+0x95/0x120 > really_probe+0x164/0x3c0 > __driver_probe_device+0x73/0x160 > driver_probe_device+0x19/0xa0 > __driver_attach+0xb6/0x180 > bus_for_each_dev+0x77/0xd0 > bus_add_driver+0x114/0x210 > driver_register+0x5b/0x110 > __pfx_vgem_open+0x3/0x10 [vgem] > do_one_initcall+0x57/0x270 > do_init_module+0x5f/0x220 > load_module+0x1ca4/0x1f00 > __do_sys_finit_module+0xb4/0x130 > do_syscall_64+0x3c/0x90 > entry_SYSCALL_64_after_hwframe+0x72/0xdc > > -> #2 (fs_reclaim){+.+.}-{0:0}: > lock_acquire+0xd8/0x2d0 > fs_reclaim_acquire+0xac/0xe0 > kmem_cache_alloc+0x32/0x260 > i915_vma_instance+0xb2/0xc60 [i915] > i915_gem_object_ggtt_pin_ww+0x175/0x370 [i915] > vm_fault_gtt+0x22d/0xf60 [i915] > __do_fault+0x2f/0x1d0 > do_pte_missing+0x4a/0xd20 > __handle_mm_fault+0x5b0/0x790 > handle_mm_fault+0xa2/0x230 > do_user_addr_fault+0x3ea/0xa10 > exc_page_fault+0x68/0x1a0 > asm_exc_page_fault+0x26/0x30 > > -> #1 (>->reset.backoff_srcu){++++}-{0:0}: > lock_acquire+0xd8/0x2d0 > _intel_gt_reset_lock+0x57/0x330 [i915] > guc_timestamp_ping+0x35/0x130 [i915] > process_one_work+0x250/0x510 > worker_thread+0x4f/0x3a0 > kthread+0xff/0x130 > ret_from_fork+0x29/0x50 > > -> #0 ((work_completion)(&(&guc->timestamp.work)->work)){+.+.}-{0:0}: > check_prev_add+0x90/0xc60 > __lock_acquire+0x1998/0x2590 > lock_acquire+0xd8/0x2d0 > __flush_work+0x74/0x530 > __cancel_work_timer+0x14f/0x1f0 > intel_guc_submission_reset_prepare+0x81/0x4b0 [i915] > intel_uc_reset_prepare+0x9c/0x120 [i915] > reset_prepare+0x21/0x60 [i915] > intel_gt_reset+0x1dd/0x470 [i915] > intel_gt_reset_global+0xfb/0x170 [i915] > intel_gt_handle_error+0x368/0x420 [i915] > intel_gt_debugfs_reset_store+0x5c/0xc0 [i915] > i915_wedged_set+0x29/0x40 [i915] > simple_attr_write_xsigned.constprop.0+0xb4/0x110 > full_proxy_write+0x52/0x80 > vfs_write+0xc5/0x4f0 > ksys_write+0x64/0xe0 > do_syscall_64+0x3c/0x90 > entry_SYSCALL_64_after_hwframe+0x72/0xdc > > other info that might help us debug this: > Chain exists of: > (work_completion)(&(&guc->timestamp.work)->work) --> fs_reclaim --> >->reset.mutex > Possible unsafe locking scenario: > CPU0 CPU1 > ---- ---- > lock(>->reset.mutex); > lock(fs_reclaim); > lock(>->reset.mutex); > lock((work_completion)(&(&guc->timestamp.work)->work)); > > *** DEADLOCK *** > 3 locks held by kms_pipe_crc_ba/6415: > #0: ffff888101541430 (sb_writers#15){.+.+}-{0:0}, at: ksys_write+0x64/0xe0 > #1: ffff888136c7eab8 (&attr->mutex){+.+.}-{3:3}, at: simple_attr_write_xsigned.constprop.0+0x47/0x110 > #2: ffff88813e6cce90 (>->reset.mutex){+.+.}-{3:3}, at: intel_gt_reset+0x19e/0x470 [i915] > > Signed-off-by: Zhanjun Dong This unlocks multiple machines on CI, thx. Reviewed-by: Andrzej Hajda Regards Andrzej > --- > drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > index a0e3ef1c65d2..22390704542e 100644 > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c > @@ -1359,7 +1359,7 @@ static void guc_enable_busyness_worker(struct intel_guc *guc) > > static void guc_cancel_busyness_worker(struct intel_guc *guc) > { > - cancel_delayed_work_sync(&guc->timestamp.work); > + cancel_delayed_work(&guc->timestamp.work); > } > > static void __reset_guc_busyness_stats(struct intel_guc *guc)