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7771590692
Ensure that the drm_i915_file_private continues to exist as we attempt
to remove a request from its list, which may race with the destruction
of the file.
<6> [38.380714] [IGT] gem_ctx_create: starting subtest basic-files
<0> [42.201329] BUG: spinlock bad magic on CPU#0, kworker/u16:0/7
<4> [42.201356] general protection fault: 0000 [#1] PREEMPT SMP PTI
<4> [42.201371] CPU: 0 PID: 7 Comm: kworker/u16:0 Tainted: G U 5.3.0-rc5-CI-Patchwork_14169+ #1
<4> [42.201391] Hardware name: Dell Inc. OptiPlex 745 /0GW726, BIOS 2.3.1 05/21/2007
<4> [42.201594] Workqueue: i915 retire_work_handler [i915]
<4> [42.201614] RIP: 0010:spin_dump+0x5a/0x90
<4> [42.201625] Code: 00 48 8d 88 c0 06 00 00 48 c7 c7 00 71 09 82 e8 35 ef 00 00 48 85 db 44 8b 4d 08 41 b8 ff ff ff ff 48 c7 c1 0b cd 0f 82 74 0e <44> 8b 83 e0 04 00 00 48 8d 8b c0 06 00 00 8b 55 04 48 89 ee 48 c7
<4> [42.201660] RSP: 0018:ffffc9000004bd80 EFLAGS: 00010202
<4> [42.201673] RAX: 0000000000000031 RBX: 6b6b6b6b6b6b6b6b RCX: ffffffff820fcd0b
<4> [42.201688] RDX: 0000000000000000 RSI: ffff88803de266f8 RDI: 00000000ffffffff
<4> [42.201703] RBP: ffff888038381ff8 R08: 00000000ffffffff R09: 000000006b6b6b6b
<4> [42.201718] R10: 0000000041cb0b89 R11: 646162206b636f6c R12: ffff88802a618500
<4> [42.201733] R13: ffff88802b32c288 R14: ffff888038381ff8 R15: ffff88802b32c250
<4> [42.201748] FS: 0000000000000000(0000) GS:ffff88803de00000(0000) knlGS:0000000000000000
<4> [42.201765] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4> [42.201778] CR2: 00007f2cefc6d180 CR3: 00000000381ee000 CR4: 00000000000006f0
<4> [42.201793] Call Trace:
<4> [42.201805] do_raw_spin_lock+0x66/0xb0
<4> [42.201898] i915_request_retire+0x548/0x7c0 [i915]
<4> [42.201989] retire_requests+0x4d/0x60 [i915]
<4> [42.202078] i915_retire_requests+0x144/0x2e0 [i915]
<4> [42.202169] retire_work_handler+0x10/0x40 [i915]
Recently, in commit 44c22f3f1a ("drm/i915: Serialize insertion into the
file->mm.request_list"), we fixed a race on insertion. Now, it appears
we also have a race with destruction!
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190823181455.31910-1-chris@chris-wilson.co.uk
71 lines
1.9 KiB
C
71 lines
1.9 KiB
C
/*
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* SPDX-License-Identifier: MIT
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*
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* Copyright © 2014-2016 Intel Corporation
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*/
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#include <linux/jiffies.h>
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#include <drm/drm_file.h>
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#include "i915_drv.h"
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#include "i915_gem_ioctls.h"
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#include "i915_gem_object.h"
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/*
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* 20ms is a fairly arbitrary limit (greater than the average frame time)
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* chosen to prevent the CPU getting more than a frame ahead of the GPU
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* (when using lax throttling for the frontbuffer). We also use it to
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* offer free GPU waitboosts for severely congested workloads.
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*/
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#define DRM_I915_THROTTLE_JIFFIES msecs_to_jiffies(20)
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/*
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* Throttle our rendering by waiting until the ring has completed our requests
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* emitted over 20 msec ago.
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*
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* Note that if we were to use the current jiffies each time around the loop,
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* we wouldn't escape the function with any frames outstanding if the time to
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* render a frame was over 20ms.
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*
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* This should get us reasonable parallelism between CPU and GPU but also
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* relatively low latency when blocking on a particular request to finish.
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*/
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int
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i915_gem_throttle_ioctl(struct drm_device *dev, void *data,
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struct drm_file *file)
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{
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struct drm_i915_file_private *file_priv = file->driver_priv;
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unsigned long recent_enough = jiffies - DRM_I915_THROTTLE_JIFFIES;
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struct i915_request *request, *target = NULL;
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long ret;
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/* ABI: return -EIO if already wedged */
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ret = intel_gt_terminally_wedged(&to_i915(dev)->gt);
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if (ret)
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return ret;
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spin_lock(&file_priv->mm.lock);
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list_for_each_entry(request, &file_priv->mm.request_list, client_link) {
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if (time_after_eq(request->emitted_jiffies, recent_enough))
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break;
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if (target && xchg(&target->file_priv, NULL))
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list_del(&target->client_link);
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target = request;
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}
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if (target)
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i915_request_get(target);
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spin_unlock(&file_priv->mm.lock);
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if (!target)
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return 0;
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ret = i915_request_wait(target,
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I915_WAIT_INTERRUPTIBLE,
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MAX_SCHEDULE_TIMEOUT);
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i915_request_put(target);
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return ret < 0 ? ret : 0;
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}
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