From patchwork Tue Jun 6 03:00:37 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Dong, Zhanjun" X-Patchwork-Id: 13268193 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 130D7C7EE23 for ; Tue, 6 Jun 2023 03:00:44 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id EF07C10E175; Tue, 6 Jun 2023 03:00:42 +0000 (UTC) Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3D76910E175; Tue, 6 Jun 2023 03:00:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1686020442; x=1717556442; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=iZqaBanXhUULXeSqb5S/giRCGYjE7XmWOqBeZSIJCE4=; b=L9kpGVdNby6dZpgWsJwkHO+1nBY82Cz+K0ATSKXfnKdMjN5mTRMCQ0uu wlfZKj1lwiVHYXykK02U6DuRg9ON3AihtegBRTnC9j8jXP62+u+0nrf2X um530u+1jB4CeEEXMarHR6dEiSMr3Q4Wj4skTLFJ3s/f2FZmJM6UUOMIm OzMjtyNuUwUGxHfRvGYwNX4sDO3UjC/z8oeVarwobXvMyrwiYx4BgEykn HrqLdy0UO9CcRgdaErkIR2SX+WRcPRiEkaV8S313uRBg7iFHSfejDyPpt rNTafaQe/xw6H+v/Xa1Me4Sy+rKtEczy4pdsFVi489tZw9hIlFCX4m/va w==; X-IronPort-AV: E=McAfee;i="6600,9927,10732"; a="336904515" X-IronPort-AV: E=Sophos;i="6.00,219,1681196400"; d="scan'208";a="336904515" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jun 2023 20:00:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10732"; a="708901567" X-IronPort-AV: E=Sophos;i="6.00,219,1681196400"; d="scan'208";a="708901567" Received: from guc-pnp-dev-box-1.fm.intel.com ([10.1.27.12]) by orsmga002.jf.intel.com with ESMTP; 05 Jun 2023 20:00:40 -0700 From: Zhanjun Dong To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: [PATCH] drm/i915: Avoid circular locking dependency when flush delayed work on gt reset Date: Mon, 5 Jun 2023 20:00:37 -0700 Message-Id: <20230606030037.196558-1-zhanjun.dong@intel.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Zhanjun Dong Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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 Reviewed-by: Andrzej Hajda --- 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)