diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2020-03-10 14:24:03 +0000 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2020-03-10 23:12:38 +0000 |
| commit | 326611ddff603ca863adfd797f9e75297ac02539 (patch) | |
| tree | 2e88b4c7094982d618e16aa63511f6367562ed58 /drivers/gpu/drm/i915/i915_request.c | |
| parent | 0690e504b66f369deb0e23b72741afcef8269e2e (diff) | |
drm/i915: Mark up racy read of active rq->engine
As a virtual engine may change the rq->engine to point to the active
request in flight, we need to warn the compiler that an active request's
engine is volatile.
[ 95.017686] write (marked) to 0xffff8881e8386b10 of 8 bytes by interrupt on cpu 2:
[ 95.018123] execlists_dequeue+0x762/0x2150 [i915]
[ 95.018539] __execlists_submission_tasklet+0x48/0x60 [i915]
[ 95.018955] execlists_submission_tasklet+0xd3/0x170 [i915]
[ 95.018986] tasklet_action_common.isra.0+0x42/0xa0
[ 95.019016] __do_softirq+0xd7/0x2cd
[ 95.019043] irq_exit+0xbe/0xe0
[ 95.019068] irq_work_interrupt+0xf/0x20
[ 95.019491] i915_request_retire+0x2c5/0x670 [i915]
[ 95.019937] retire_requests+0xa1/0xf0 [i915]
[ 95.020348] engine_retire+0xa1/0xe0 [i915]
[ 95.020376] process_one_work+0x3b1/0x690
[ 95.020403] worker_thread+0x80/0x670
[ 95.020429] kthread+0x19a/0x1e0
[ 95.020454] ret_from_fork+0x1f/0x30
[ 95.020476]
[ 95.020498] read to 0xffff8881e8386b10 of 8 bytes by task 8909 on cpu 3:
[ 95.020918] __i915_request_commit+0x177/0x220 [i915]
[ 95.021329] i915_gem_do_execbuffer+0x38c4/0x4e50 [i915]
[ 95.021750] i915_gem_execbuffer2_ioctl+0x2c3/0x580 [i915]
[ 95.021784] drm_ioctl_kernel+0xe4/0x120
[ 95.021809] drm_ioctl+0x297/0x4c7
[ 95.021832] ksys_ioctl+0x89/0xb0
[ 95.021865] __x64_sys_ioctl+0x42/0x60
[ 95.021901] do_syscall_64+0x6e/0x2c0
[ 95.021927] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200310142403.5953-1-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/i915/i915_request.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_request.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index 74169671afb5..c0df71d7d0ff 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -977,6 +977,8 @@ emit_semaphore_wait(struct i915_request *to, struct i915_request *from, gfp_t gfp) { + const intel_engine_mask_t mask = READ_ONCE(from->engine)->mask; + if (!intel_context_use_semaphores(to->context)) goto await_fence; @@ -984,7 +986,7 @@ emit_semaphore_wait(struct i915_request *to, goto await_fence; /* Just emit the first semaphore we see as request space is limited. */ - if (already_busywaiting(to) & from->engine->mask) + if (already_busywaiting(to) & mask) goto await_fence; if (i915_request_await_start(to, from) < 0) @@ -997,7 +999,7 @@ emit_semaphore_wait(struct i915_request *to, if (__emit_semaphore_wait(to, from, from->fence.seqno)) goto await_fence; - to->sched.semaphores |= from->engine->mask; + to->sched.semaphores |= mask; to->sched.flags |= I915_SCHED_HAS_SEMAPHORE_CHAIN; return 0; @@ -1338,7 +1340,7 @@ __i915_request_add_to_timeline(struct i915_request *rq) i915_seqno_passed(prev->fence.seqno, rq->fence.seqno)); - if (is_power_of_2(prev->engine->mask | rq->engine->mask)) + if (is_power_of_2(READ_ONCE(prev->engine)->mask | rq->engine->mask)) i915_sw_fence_await_sw_fence(&rq->submit, &prev->submit, &rq->submitq); |