From patchwork Thu Sep 15 16:52:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Janusz Krzysztofik X-Patchwork-Id: 12977662 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 7B9CDC6FA89 for ; Thu, 15 Sep 2022 16:52:33 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id F3CA410E21E; Thu, 15 Sep 2022 16:52:31 +0000 (UTC) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id BC1FB10EB7A; Thu, 15 Sep 2022 16:52:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1663260748; x=1694796748; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=pnw/TWt9EuTrzwHAnGTFiTqRLLQoYn1rh+M5pSCoGzg=; b=fqn/wrarbQ/BcIsJm7iAAi69rI5em+xH74+6BO7xwd2RCbHerLsZ/PK9 VpaFiyzy+XE9Oj5utQWVZ7MO1yrOMrUQ5+TblCxU6+Fb6M064eZZnTnyf QxblfBWGoCmZT0ev+Vjhe31CukLPQTRpsNGZl1y05Lw7dR/hC4L7kBpS8 urblho3C9PoenizSJCjKXCJbKTsEPlQBtko0Vd+RjJ0eY25g+VrZCc6OV impO0nP1YLCIhRMr7cBYnnfdifGR7Ae9wc1w1MyFtrcsw1LRc7xD+qxnO txE6XuX2TD6LMigGGnfZrdcKD/55+o8NMQLmizVDYTbOl1O+2B1NYw+M0 Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10471"; a="297497950" X-IronPort-AV: E=Sophos;i="5.93,318,1654585200"; d="scan'208";a="297497950" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2022 09:52:28 -0700 X-IronPort-AV: E=Sophos;i="5.93,318,1654585200"; d="scan'208";a="568501597" Received: from jkrzyszt-mobl1.ger.corp.intel.com (HELO jkrzyszt-mobl1.lan) ([10.213.25.71]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2022 09:52:25 -0700 From: Janusz Krzysztofik To: intel-gfx@lists.freedesktop.org Subject: [PATCH v2 0/2] drm/i915/gem: Really move i915_gem_context.link under ref protection Date: Thu, 15 Sep 2022 18:52:08 +0200 Message-Id: <20220915165210.193197-1-janusz.krzysztofik@linux.intel.com> X-Mailer: git-send-email 2.25.1 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: Tvrtko Ursulin , dri-devel@lists.freedesktop.org, Chris Wilson , Andi Shyti , Janusz Krzysztofik Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" i915_perf assumes that it can use the i915_gem_context reference to protect its i915->gem.contexts.list iteration. However, this requires that we do not remove the context from the list until after we drop the final reference and release the struct. If, as currently, we remove the context from the list during context_close(), the link.next pointer may be poisoned while we are holding the context reference and cause a GPF: [ 4070.573157] i915 0000:00:02.0: [drm:i915_perf_open_ioctl [i915]] filtering on ctx_id=0x 1fffff ctx_id_mask=0x1fffff [ 4070.574881] general protection fault, probably for non-canonical address 0xdead00000000 0100: 0000 [#1] PREEMPT SMP [ 4070.574897] CPU: 1 PID: 284392 Comm: amd_performance Tainted: G E 5.17.9 #180 [ 4070.574903] Hardware name: Intel Corporation NUC7i5BNK/NUC7i5BNB, BIOS BNKBL357.86A.0052.2017.0918.1346 09/18/2017 [ 4070.574907] RIP: 0010:oa_configure_all_contexts.isra.0+0x222/0x350 [i915] [ 4070.574982] Code: 08 e8 32 6e 10 e1 4d 8b 6d 50 b8 ff ff ff ff 49 83 ed 50 f0 41 0f c1 04 24 83 f8 01 0f 84 e3 00 00 00 85 c0 0f 8e fa 00 00 00 <49> 8b 45 50 48 8d 70 b0 49 8d 45 50 48 39 44 24 10 0f 85 34 fe ff [ 4070.574990] RSP: 0018:ffffc90002077b78 EFLAGS: 00010202 [ 4070.574995] RAX: 0000000000000002 RBX: 0000000000000002 RCX: 0000000000000000 [ 4070.575000] RDX: 0000000000000001 RSI: ffffc90002077b20 RDI: ffff88810ddc7c68 [ 4070.575004] RBP: 0000000000000001 R08: ffff888103242648 R09: fffffffffffffffc [ 4070.575008] R10: ffffffff82c50bc0 R11: 0000000000025c80 R12: ffff888101bf1860 [ 4070.575012] R13: dead0000000000b0 R14: ffffc90002077c04 R15: ffff88810be5cabc [ 4070.575016] FS: 00007f1ed50c0780(0000) GS:ffff88885ec80000(0000) knlGS:0000000000000000 [ 4070.575021] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 4070.575025] CR2: 00007f1ed5590280 CR3: 000000010ef6f005 CR4: 00000000003706e0 [ 4070.575029] Call Trace: [ 4070.575033] [ 4070.575037] lrc_configure_all_contexts+0x13e/0x150 [i915] [ 4070.575103] gen8_enable_metric_set+0x4d/0x90 [i915] [ 4070.575164] i915_perf_open_ioctl+0xbc0/0x1500 [i915] [ 4070.575224] ? asm_common_interrupt+0x1e/0x40 [ 4070.575232] ? i915_oa_init_reg_state+0x110/0x110 [i915] [ 4070.575290] drm_ioctl_kernel+0x85/0x110 [ 4070.575296] ? update_load_avg+0x5f/0x5e0 [ 4070.575302] drm_ioctl+0x1d3/0x370 [ 4070.575307] ? i915_oa_init_reg_state+0x110/0x110 [i915] [ 4070.575382] ? gen8_gt_irq_handler+0x46/0x130 [i915] [ 4070.575445] __x64_sys_ioctl+0x3c4/0x8d0 [ 4070.575451] ? __do_softirq+0xaa/0x1d2 [ 4070.575456] do_syscall_64+0x35/0x80 [ 4070.575461] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 4070.575467] RIP: 0033:0x7f1ed5c10397 [ 4070.575471] Code: 3c 1c e8 1c ff ff ff 85 c0 79 87 49 c7 c4 ff ff ff ff 5b 5d 4c 89 e0 41 5c c3 66 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a9 da 0d 00 f7 d8 64 89 01 48 [ 4070.575478] RSP: 002b:00007ffd65c8d7a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 4070.575484] RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007f1ed5c10397 [ 4070.575488] RDX: 00007ffd65c8d7c0 RSI: 0000000040106476 RDI: 0000000000000006 [ 4070.575492] RBP: 00005620972f9c60 R08: 000000000000000a R09: 0000000000000005 [ 4070.575496] R10: 000000000000000d R11: 0000000000000246 R12: 000000000000000a [ 4070.575500] R13: 000000000000000d R14: 0000000000000000 R15: 00007ffd65c8d7c0 [ 4070.575505] [ 4070.575507] Modules linked in: nls_ascii(E) nls_cp437(E) vfat(E) fat(E) i915(E) x86_pkg_temp_thermal(E) intel_powerclamp(E) crct10dif_pclmul(E) crc32_pclmul(E) crc32c_intel(E) aesni_intel(E) crypto_simd(E) intel_gtt(E) cryptd(E) ttm(E) rapl(E) intel_cstate(E) drm_kms_helper(E) cfbfillrect(E) syscopyarea(E) cfbimgblt(E) intel_uncore(E) sysfillrect(E) mei_me(E) sysimgblt(E) i2c_i801(E) fb_sys_fops(E) mei(E) intel_pch_thermal(E) i2c_smbus(E) cfbcopyarea(E) video(E) button(E) efivarfs(E) autofs4(E) [ 4070.575549] ---[ end trace 0000000000000000 ]--- However, there is a risk of triggering kernel warning on contexts list not empty at driver release time if we deleagate that task to a worker for i915_gem_context_release_work(), unless that work is flushed first. Unfortunately, it is not flushed on driver release. Fix it. Chris Wilson (1): drm/i915/gem: Really move i915_gem_context.link under ref protection Janusz Krzysztofik (1): drm/i915/gem: Flush contexts on driver release drivers/gpu/drm/i915/gem/i915_gem_context.c | 8 ++++---- drivers/gpu/drm/i915/i915_gem.c | 3 ++- 2 files changed, 6 insertions(+), 5 deletions(-)