From patchwork Tue May 8 15:35:14 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 10386391 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id C69A660353 for ; Tue, 8 May 2018 15:35:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B603B28793 for ; Tue, 8 May 2018 15:35:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AAE6328E7E; Tue, 8 May 2018 15:35:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 32E3B28793 for ; Tue, 8 May 2018 15:35:31 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8BD696EACA; Tue, 8 May 2018 15:35:30 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id 76BC76EACA for ; Tue, 8 May 2018 15:35:29 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from haswell.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 11634661-1500050 for multiple; Tue, 08 May 2018 16:35:14 +0100 Received: by haswell.alporthouse.com (sSMTP sendmail emulation); Tue, 08 May 2018 16:35:15 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Tue, 8 May 2018 16:35:14 +0100 Message-Id: <20180508153514.20251-1-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.17.0 X-Originating-IP: 78.156.65.138 X-Country: code=GB country="United Kingdom" ip=78.156.65.138 Subject: [Intel-gfx] [PATCH] drm/i915: Annotate timeline lock nesting X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP CI noticed <4>[ 23.430701] ============================================ <4>[ 23.430706] WARNING: possible recursive locking detected <4>[ 23.430713] 4.17.0-rc4-CI-CI_DRM_4156+ #1 Not tainted <4>[ 23.430720] -------------------------------------------- <4>[ 23.430725] systemd-udevd/169 is trying to acquire lock: <4>[ 23.430732] (ptrval) (&(&timeline->lock)->rlock){....}, at: move_to_timeline+0x48/0x12c [i915] <4>[ 23.430888] but task is already holding lock: <4>[ 23.430894] (ptrval) (&(&timeline->lock)->rlock){....}, at: i915_request_submit+0x1a/0x40 [i915] <4>[ 23.430995] other info that might help us debug this: <4>[ 23.431002] Possible unsafe locking scenario: <4>[ 23.431007] CPU0 <4>[ 23.431010] ---- <4>[ 23.431013] lock(&(&timeline->lock)->rlock); <4>[ 23.431021] lock(&(&timeline->lock)->rlock); <4>[ 23.431028] *** DEADLOCK *** <4>[ 23.431036] May be due to missing lock nesting notation <4>[ 23.431044] 5 locks held by systemd-udevd/169: <4>[ 23.431049] #0: (ptrval) (&dev->mutex){....}, at: __driver_attach+0x42/0xe0 <4>[ 23.431065] #1: (ptrval) (&dev->mutex){....}, at: __driver_attach+0x50/0xe0 <4>[ 23.431078] #2: (ptrval) (&dev->struct_mutex){+.+.}, at: i915_gem_init+0xca/0x630 [i915] <4>[ 23.431174] #3: (ptrval) (rcu_read_lock){....}, at: submit_notify+0x35/0x124 [i915] <4>[ 23.431271] #4: (ptrval) (&(&timeline->lock)->rlock){....}, at: i915_request_submit+0x1a/0x40 [i915] <4>[ 23.431369] stack backtrace: <4>[ 23.431377] CPU: 0 PID: 169 Comm: systemd-udevd Not tainted 4.17.0-rc4-CI-CI_DRM_4156+ #1 <4>[ 23.431385] Hardware name: Dell Inc. OptiPlex GX280 /0G8310, BIOS A04 02/09/2005 <4>[ 23.431394] Call Trace: <4>[ 23.431403] dump_stack+0x67/0x9b <4>[ 23.431411] __lock_acquire+0xc67/0x1b50 <4>[ 23.431421] ? ring_buffer_lock_reserve+0x154/0x3f0 <4>[ 23.431429] ? lock_acquire+0xa6/0x210 <4>[ 23.431435] lock_acquire+0xa6/0x210 <4>[ 23.431530] ? move_to_timeline+0x48/0x12c [i915] <4>[ 23.431540] _raw_spin_lock+0x2a/0x40 <4>[ 23.431634] ? move_to_timeline+0x48/0x12c [i915] <4>[ 23.431730] move_to_timeline+0x48/0x12c [i915] <4>[ 23.431826] __i915_request_submit+0xfa/0x280 [i915] <4>[ 23.431923] i915_request_submit+0x25/0x40 [i915] <4>[ 23.432024] i9xx_submit_request+0x11/0x140 [i915] <4>[ 23.432120] submit_notify+0x8d/0x124 [i915] <4>[ 23.432202] __i915_sw_fence_complete+0x81/0x250 [i915] <4>[ 23.432300] __i915_request_add+0x31c/0x7c0 [i915] <4>[ 23.432395] i915_gem_init+0x621/0x630 [i915] <4>[ 23.432476] i915_driver_load+0xbee/0x10b0 [i915] <4>[ 23.432485] ? trace_hardirqs_on_caller+0xe0/0x1b0 <4>[ 23.432566] i915_pci_probe+0x29/0x90 [i915] <4>[ 23.432574] pci_device_probe+0xa1/0x130 <4>[ 23.432582] driver_probe_device+0x306/0x480 <4>[ 23.432589] __driver_attach+0xb7/0xe0 <4>[ 23.432596] ? driver_probe_device+0x480/0x480 <4>[ 23.432602] ? driver_probe_device+0x480/0x480 <4>[ 23.432609] bus_for_each_dev+0x74/0xc0 <4>[ 23.432616] bus_add_driver+0x15f/0x250 <4>[ 23.432623] ? 0xffffffffa02d7000 <4>[ 23.432629] driver_register+0x52/0xc0 <4>[ 23.432635] ? 0xffffffffa02d7000 <4>[ 23.432642] do_one_initcall+0x58/0x370 <4>[ 23.432653] ? do_init_module+0x1d/0x1ea <4>[ 23.432660] ? rcu_read_lock_sched_held+0x6f/0x80 <4>[ 23.432667] ? kmem_cache_alloc_trace+0x282/0x2e0 <4>[ 23.432675] do_init_module+0x56/0x1ea <4>[ 23.432682] load_module+0x2435/0x2b20 <4>[ 23.432694] ? __se_sys_finit_module+0xd3/0xf0 <4>[ 23.432701] __se_sys_finit_module+0xd3/0xf0 <4>[ 23.432710] do_syscall_64+0x55/0x190 <4>[ 23.432717] entry_SYSCALL_64_after_hwframe+0x49/0xbe <4>[ 23.432724] RIP: 0033:0x7fa780782839 <4>[ 23.432729] RSP: 002b:00007ffcea73e668 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 <4>[ 23.432738] RAX: ffffffffffffffda RBX: 0000561a472a4b30 RCX: 00007fa780782839 <4>[ 23.432745] RDX: 0000000000000000 RSI: 00007fa7804610e5 RDI: 000000000000000e <4>[ 23.432752] RBP: 00007fa7804610e5 R08: 0000000000000000 R09: 00007ffcea73e780 <4>[ 23.432758] R10: 000000000000000e R11: 0000000000000246 R12: 0000000000000000 <4>[ 23.432765] R13: 0000561a47296450 R14: 0000000000020000 R15: 0000561a472a4b30 but did not report it as an issue as it only occurred during the first module on boot. This is due to the removal of the distinct global timeline, and its separate lock class. So instead mark up the expected nesting. An alternative would be to define a separate lock class for the engine, but since we only expect to have a single point of nesting, we can avoid having multiple lock classes for the struct. Fixes: a89d1f921c15 ("drm/i915: Split i915_gem_timeline into individual timelines") Signed-off-by: Chris Wilson Cc: Chris Wilson Cc: Tvrtko Ursulin Cc: Joonas Lahtinen Tested-by: Michel Thierry Reviewed-by: Tvrtko Ursulin --- drivers/gpu/drm/i915/i915_request.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index f336942229cf..8928894dd9c7 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -502,7 +502,7 @@ static void move_to_timeline(struct i915_request *request, GEM_BUG_ON(request->timeline == &request->engine->timeline); lockdep_assert_held(&request->engine->timeline.lock); - spin_lock(&request->timeline->lock); + spin_lock_nested(&request->timeline->lock, SINGLE_DEPTH_NESTING); list_move_tail(&request->link, &timeline->requests); spin_unlock(&request->timeline->lock); }