Chris Wilson <[email protected]> writes: > 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 <[email protected]>
Reviewed-by: Mika Kuoppala <[email protected]> > --- > drivers/gpu/drm/i915/i915_request.c | 8 +++++--- > 1 file 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); > -- > 2.20.1 > > _______________________________________________ > Intel-gfx mailing list > [email protected] > https://lists.freedesktop.org/mailman/listinfo/intel-gfx _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
