9:08 p.m.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 0062442ecfef0d82cd69e3e600d5006357f8d8e4
commit: 27a5dcfe73f4b696b3de8c23a560199bb1c193a4 drm/i915/gem: Remove disordered per-file
request list for throttling
config: i386-randconfig-m021-20201115 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp(a)intel.com>
Reported-by: Dan Carpenter <dan.carpenter(a)oracle.com>
smatch warnings:
drivers/gpu/drm/i915/gem/i915_gem_throttle.c:59 i915_gem_throttle_ioctl() error: double
locked 'ctx->engines_mutex' (orig line 59)
vim +59 drivers/gpu/drm/i915/gem/i915_gem_throttle.c
35 int
36 i915_gem_throttle_ioctl(struct drm_device *dev, void *data,
37 struct drm_file *file)
38 {
39 const unsigned long recent_enough = jiffies - DRM_I915_THROTTLE_JIFFIES;
40 struct drm_i915_file_private *file_priv = file->driver_priv;
41 struct i915_gem_context *ctx;
42 unsigned long idx;
43 long ret;
44
45 /* ABI: return -EIO if already wedged */
46 ret = intel_gt_terminally_wedged(&to_i915(dev)->gt);
47 if (ret)
48 return ret;
49
50 rcu_read_lock();
51 xa_for_each(&file_priv->context_xa, idx, ctx) {
52 struct i915_gem_engines_iter it;
53 struct intel_context *ce;
54
55 if (!kref_get_unless_zero(&ctx->ref))
56 continue;
57 rcu_read_unlock();
58
59 for_each_gem_engine(ce,
60 i915_gem_context_lock_engines(ctx),
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I don't understand why this takes the lock every iteration through the
loop
61 it) {
62 struct i915_request *rq, *target = NULL;
63
64 if (!ce->timeline)
65 continue;
66
67 mutex_lock(&ce->timeline->mutex);
68 list_for_each_entry_reverse(rq,
69
&ce->timeline->requests,
70 link) {
71 if (i915_request_completed(rq))
72 break;
73
74 if (time_after(rq->emitted_jiffies,
75 recent_enough))
76 continue;
77
78 target = i915_request_get(rq);
79 break;
80 }
81 mutex_unlock(&ce->timeline->mutex);
82 if (!target)
83 continue;
84
85 ret = i915_request_wait(target,
86 I915_WAIT_INTERRUPTIBLE,
87 MAX_SCHEDULE_TIMEOUT);
88 i915_request_put(target);
89 if (ret < 0)
90 break;
91 }
92 i915_gem_context_unlock_engines(ctx);
But only unlocks the last element
93 i915_gem_context_put(ctx);
94
95 rcu_read_lock();
96 }
97 rcu_read_unlock();
98
99 return ret < 0 ? ret : 0;
100 }
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org