From patchwork Fri Dec 6 11:56:35 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuansheng Liu X-Patchwork-Id: 11276017 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DF014109A for ; Fri, 6 Dec 2019 11:57:13 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id C2A3A2464E for ; Fri, 6 Dec 2019 11:57:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C2A3A2464E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9A6CE6F9DA; Fri, 6 Dec 2019 11:57:12 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by gabe.freedesktop.org (Postfix) with ESMTPS id 14BF36F9DA for ; Fri, 6 Dec 2019 11:57:10 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Dec 2019 03:57:10 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,284,1571727600"; d="scan'208";a="294839321" Received: from cliu38-mobl3.sh.intel.com (HELO 286ab234718b.sh.intel.com) ([10.239.147.26]) by orsmga001.jf.intel.com with ESMTP; 06 Dec 2019 03:57:09 -0800 From: Chuansheng Liu To: intel-gfx@lists.freedesktop.org Date: Fri, 6 Dec 2019 11:56:35 +0000 Message-Id: <20191206115635.46931-1-chuansheng.liu@intel.com> X-Mailer: git-send-email 2.17.1 Subject: [Intel-gfx] [PATCH] drm/i915: Fix the use-after-free between i915_active_ref and __active_retire 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" We easily hit drm/i915 panic on TGL when running glmark2, and finally caught the race condition of use-after-free with enabling KASAN. The call stack is below: === [ 534.472675] BUG: KASAN: use-after-free in __i915_active_fence_set+0x26d/0x3d0 [i915] [ 534.472679] Write of size 8 at addr ffff8883f0372388 by task glmark2/3199 [ 534.472684] CPU: 3 PID: 3199 Comm: glmark2 Tainted: G U E 5.4.0-rc8 #8 [ 534.472687] Call Trace: [ 534.472693] dump_stack+0x95/0xd5 [ 534.472722] ? __i915_active_fence_set+0x26d/0x3d0 [i915] [ 534.472727] print_address_description.constprop.5+0x20/0x320 [ 534.472751] ? __i915_active_fence_set+0x26d/0x3d0 [i915] [ 534.472792] ? __i915_active_fence_set+0x26d/0x3d0 [i915] [ 534.472794] __kasan_report+0x149/0x18c [ 534.472798] ? _raw_spin_lock+0x1/0xd0 [ 534.472820] ? __i915_active_fence_set+0x26d/0x3d0 [i915] [ 534.472822] kasan_report+0x12/0x20 [ 534.472825] __asan_report_store8_noabort+0x17/0x20 [ 534.472847] __i915_active_fence_set+0x26d/0x3d0 [i915] [ 534.472870] i915_active_ref+0x2c8/0x530 [i915] [ 534.472874] ? dma_resv_add_shared_fence+0x291/0x460 [ 534.472902] __i915_vma_move_to_active+0x56/0x70 [i915] [ 534.472927] i915_vma_move_to_active+0x54/0x420 [i915] [ 534.472931] ? mutex_unlock+0x22/0x40 [ 534.472957] i915_gem_do_execbuffer+0x1d45/0x3e20 [i915] [ 534.472959] ? __kmalloc_node+0x12c/0x350 [ 534.472983] ? eb_relocate_slow+0xb40/0xb40 [i915] [ 534.472985] ? _raw_write_trylock+0x110/0x110 [ 534.472987] ? get_partial_node.isra.72+0x51/0x260 [ 534.472991] ? unix_stream_read_generic+0x583/0x1a80 [ 534.472994] ? ___slab_alloc+0x1d8/0x550 [ 534.472998] ? kvmalloc_node+0x31/0x80 [ 534.473000] ? kasan_unpoison_shadow+0x35/0x50 [ 534.473002] ? _raw_spin_lock+0x7b/0xd0 [ 534.473004] ? radix_tree_lookup+0xd/0x10 [ 534.473006] ? idr_find+0x3b/0x60 [ 534.473029] i915_gem_execbuffer2_ioctl+0x634/0x8a0 [i915] [ 534.473052] ? i915_gem_execbuffer_ioctl+0xd50/0xd50 [i915] [ 534.473054] ? unix_stream_recvmsg+0x97/0xd0 [ 534.473056] ? unix_stream_splice_read+0x1c0/0x1c0 [ 534.473058] ? __unix_insert_socket+0x180/0x180 [ 534.473081] ? i915_gem_execbuffer_ioctl+0xd50/0xd50 [i915] [ 534.473094] drm_ioctl_kernel+0x1ed/0x2b0 [drm] [ 534.473103] ? drm_setversion+0x8c0/0x8c0 [drm] [ 534.473106] ? __kasan_check_write+0x14/0x20 [ 534.473115] drm_ioctl+0x68b/0xaa0 [drm] ... [ 534.473239] Allocated by task 3199: [ 534.473241] save_stack+0x21/0x90 [ 534.473243] __kasan_kmalloc.constprop.8+0xa7/0xd0 [ 534.473245] kasan_slab_alloc+0x11/0x20 [ 534.473246] kmem_cache_alloc+0xce/0x240 [ 534.473273] i915_active_ref+0xc2/0x530 [i915] [ 534.473302] __i915_vma_move_to_active+0x56/0x70 [i915] [ 534.473328] i915_vma_move_to_active+0x54/0x420 [i915] [ 534.473355] i915_gem_do_execbuffer+0x1d45/0x3e20 [i915] [ 534.473381] i915_gem_execbuffer2_ioctl+0x634/0x8a0 [i915] [ 534.473392] drm_ioctl_kernel+0x1ed/0x2b0 [drm] [ 534.473402] drm_ioctl+0x68b/0xaa0 [drm] [ 534.473404] do_vfs_ioctl+0x19a/0xf10 [ 534.473405] ksys_ioctl+0x75/0x80 [ 534.473407] __x64_sys_ioctl+0x73/0xb0 [ 534.473408] do_syscall_64+0x9f/0x3a0 [ 534.473410] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 534.473412] Freed by task 0: [ 534.473414] save_stack+0x21/0x90 [ 534.473415] __kasan_slab_free+0x137/0x190 [ 534.473417] kasan_slab_free+0xe/0x10 [ 534.473418] kmem_cache_free+0xeb/0x2c0 [ 534.473444] __active_retire+0x1f2/0x240 [i915] [ 534.473471] active_retire+0x13b/0x1b0 [i915] [ 534.473496] node_retire+0x54/0x80 [i915] [ 534.473523] intel_engine_breadcrumbs_irq+0x5f0/0xd10 [i915] [ 534.473549] cs_irq_handler+0x66/0xb0 [i915] [ 534.473575] gen11_gt_irq_handler+0x26c/0x400 [i915] [ 534.473600] gen11_irq_handler+0xc3/0x250 [i915] [ 534.473603] __handle_irq_event_percpu+0xe0/0x4c0 [ 534.473605] handle_irq_event_percpu+0x71/0x140 [ 534.473606] handle_irq_event+0xad/0x140 [ 534.473608] handle_edge_irq+0x1f6/0x780 [ 534.473610] do_IRQ+0x9f/0x1f0 [ 534.473612] The buggy address belongs to the object at ffff8883f0372380 which belongs to the cache active_node of size 72 [ 534.473615] The buggy address is located 8 bytes inside of === The race scenerio is like: Initially ref->count is 1, interrupt handler is trying to free the node. === CPUA in interrupt context CPUB in i915_gem_execbuffer2_ioctl __active_retire --> spin_lock(&ref->tree_lock) decrease ref->count to 0 i915_active_ref --> increase ref->count to 1 (i915_active_acquire) get the dirty ref->cache (READ_ONCE(ref->cache)) return the dirty node set ref->cache to NULL spin_unlock(&ref->tree_lock) free the node hit use-after-free in __i915_active_fence_set() === Here we need to use spinlock ref->tree_lock to protect the access of READ_ONCE(ref->cache), then the race scenerio can be resolved. with this patch, it passed our stress test for a very long time. Signed-off-by: Chuansheng Liu --- drivers/gpu/drm/i915/i915_active.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c index dca15ace88f6..3d68b910e949 100644 --- a/drivers/gpu/drm/i915/i915_active.c +++ b/drivers/gpu/drm/i915/i915_active.c @@ -214,7 +214,10 @@ active_instance(struct i915_active *ref, struct intel_timeline *tl) * after the previous activity has been retired, or if it matches the * current timeline. */ + spin_lock_irq(&ref->tree_lock); node = READ_ONCE(ref->cache); + spin_unlock_irq(&ref->tree_lock); + if (node && node->timeline == idx) return &node->base;