[PATCH] drm/amdgpu: fix the null pointer to get timeline by scheduler fence
Nayan Deshmukh
nayan26deshmukh at gmail.com
Wed Aug 8 12:00:17 UTC 2018
On Wed, Aug 8, 2018 at 4:58 PM Huang Rui <ray.huang at amd.com> wrote:
> On Wed, Aug 08, 2018 at 03:10:07PM +0800, Koenig, Christian wrote:
> > Yeah that is a known issue, but this solution is not correct either.
> >
> > See the scheduler where the job is execute on is simply not determined
> > yet when we want to trace it.
> >
> > So using the scheduler name from the entity is wrong as well.
> >
> > We should probably move the reschedule from drm_sched_entity_push_job()
> > to drm_sched_job_init() to fix that.
>
> Could you please explain why move reschedule along can fix the issue.
> Seemingly, only s_fence's sched is written to entity rq's sched, it can
> avoid the issue.
>
> sched_job->s_fence->sched = entity->rq->sched
>
> Because entity->rq->sched may not necessarily be the scheduler on which
this job will get scheduled. And assigning a wrong scheduler could lead to
wrong dependency optimizations. Hence it was assigned NULL initially we
don't know scheduler it will be scheduled on to avoid any wrong
optimizations.
Cheers,
Nayan
> Thanks,
> Ray
>
> >
> > I will prepare a patch for that today,
> > Christian.
> >
> > Am 08.08.2018 um 09:05 schrieb Huang Rui:
> > > We won't initialize fence scheduler in drm_sched_fence_create()
> anymore, so it
> > > will refer null fence scheduler if open trace event to get the
> timeline name.
> > > Actually, it is the scheduler name from the entity, so add a macro to
> replace
> > > legacy getting timeline name by job.
> > >
> > > [ 212.844281] BUG: unable to handle kernel NULL pointer dereference
> at 0000000000000018
> > > [ 212.852401] PGD 8000000427c13067 P4D 8000000427c13067 PUD 4235fc067
> PMD 0
> > > [ 212.859419] Oops: 0000 [#1] SMP PTI
> > > [ 212.862981] CPU: 4 PID: 1520 Comm: amdgpu_test Tainted: G
> OE 4.18.0-rc1-custom #1
> > > [ 212.872194] Hardware name: Gigabyte Technology Co., Ltd.
> Z170XP-SLI/Z170XP-SLI-CF, BIOS F20 11/04/2016
> > > [ 212.881704] RIP: 0010:drm_sched_fence_get_timeline_name+0x2b/0x30
> [gpu_sched]
> > > [ 212.888948] Code: 1f 44 00 00 48 8b 47 08 48 3d c0 b1 4f c0 74 13
> 48 83 ef 60 48 3d 60 b1 4f c0 b8 00 00 00 00 48 0f 45 f8 48 8b 87 e0 00 00
> 00 <48> 8b 40 18 c3 0f 1f 44 00 00 b8 01 00 00 00 c3 0f 1f 44 00 00 0f
> > > [ 212.908162] RSP: 0018:ffffa3ed81f27af0 EFLAGS: 00010246
> > > [ 212.913483] RAX: 0000000000000000 RBX: 0000000000070034 RCX:
> ffffa3ed81f27da8
> > > [ 212.920735] RDX: ffff8f24ebfb5460 RSI: ffff8f24e40d3c00 RDI:
> ffff8f24ebfb5400
> > > [ 212.928008] RBP: ffff8f24e40d3c00 R08: 0000000000000000 R09:
> ffffffffae4deafc
> > > [ 212.935263] R10: ffffffffada000ed R11: 0000000000000001 R12:
> ffff8f24e891f898
> > > [ 212.942558] R13: 0000000000000000 R14: ffff8f24ebc46000 R15:
> ffff8f24e3de97a8
> > > [ 212.949796] FS: 00007ffff7fd2700(0000) GS:ffff8f24fed00000(0000)
> knlGS:0000000000000000
> > > [ 212.958047] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > [ 212.963921] CR2: 0000000000000018 CR3: 0000000423422003 CR4:
> 00000000003606e0
> > > [ 212.971201] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> 0000000000000000
> > > [ 212.978482] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
> 0000000000000400
> > > [ 212.985720] Call Trace:
> > > [ 212.988236] trace_event_raw_event_amdgpu_cs_ioctl+0x4c/0x170
> [amdgpu]
> > > [ 212.994904] ? amdgpu_ctx_add_fence+0xa9/0x110 [amdgpu]
> > > [ 213.000246] ? amdgpu_job_free_resources+0x4b/0x70 [amdgpu]
> > > [ 213.005944] amdgpu_cs_ioctl+0x16d1/0x1b50 [amdgpu]
> > > [ 213.010920] ? amdgpu_cs_find_mapping+0xf0/0xf0 [amdgpu]
> > > [ 213.016354] drm_ioctl_kernel+0x8a/0xd0 [drm]
> > > [ 213.020794] ? recalc_sigpending+0x17/0x50
> > > [ 213.024965] drm_ioctl+0x2d7/0x390 [drm]
> > > [ 213.028979] ? amdgpu_cs_find_mapping+0xf0/0xf0 [amdgpu]
> > > [ 213.034366] ? do_signal+0x36/0x700
> > > [ 213.037928] ? signal_wake_up_state+0x15/0x30
> > > [ 213.042375] amdgpu_drm_ioctl+0x46/0x80 [amdgpu]
> > >
> > > Signed-off-by: Huang Rui <ray.huang at amd.com>
> > > ---
> > > drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 2 +-
> > > drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h | 10 ++++++----
> > > 2 files changed, 7 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > > index e12871d..be01e1b 100644
> > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> > > @@ -1247,7 +1247,7 @@ static int amdgpu_cs_submit(struct
> amdgpu_cs_parser *p,
> > >
> > > amdgpu_job_free_resources(job);
> > >
> > > - trace_amdgpu_cs_ioctl(job);
> > > + trace_amdgpu_cs_ioctl(job, entity);
> > > amdgpu_vm_bo_trace_cs(&fpriv->vm, &p->ticket);
> > > priority = job->base.s_priority;
> > > drm_sched_entity_push_job(&job->base, entity);
> > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
> > > index 8c2dab2..25cdcb7 100644
> > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
> > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
> > > @@ -36,6 +36,8 @@
> > >
> > > #define AMDGPU_JOB_GET_TIMELINE_NAME(job) \
> > >
> job->base.s_fence->finished.ops->get_timeline_name(&job->base.s_fence->finished)
> > > +#define AMDGPU_GET_SCHED_NAME(entity) \
> > > + (entity->rq->sched->name)
> > >
> > > TRACE_EVENT(amdgpu_mm_rreg,
> > > TP_PROTO(unsigned did, uint32_t reg, uint32_t value),
> > > @@ -161,11 +163,11 @@ TRACE_EVENT(amdgpu_cs,
> > > );
> > >
> > > TRACE_EVENT(amdgpu_cs_ioctl,
> > > - TP_PROTO(struct amdgpu_job *job),
> > > - TP_ARGS(job),
> > > + TP_PROTO(struct amdgpu_job *job, struct drm_sched_entity
> *entity),
> > > + TP_ARGS(job, entity),
> > > TP_STRUCT__entry(
> > > __field(uint64_t, sched_job_id)
> > > - __string(timeline,
> AMDGPU_JOB_GET_TIMELINE_NAME(job))
> > > + __string(timeline,
> AMDGPU_GET_SCHED_NAME(entity))
> > > __field(unsigned int, context)
> > > __field(unsigned int, seqno)
> > > __field(struct dma_fence *, fence)
> > > @@ -175,7 +177,7 @@ TRACE_EVENT(amdgpu_cs_ioctl,
> > >
> > > TP_fast_assign(
> > > __entry->sched_job_id = job->base.id;
> > > - __assign_str(timeline,
> AMDGPU_JOB_GET_TIMELINE_NAME(job))
> > > + __assign_str(timeline,
> AMDGPU_GET_SCHED_NAME(entity))
> > > __entry->context =
> job->base.s_fence->finished.context;
> > > __entry->seqno =
> job->base.s_fence->finished.seqno;
> > > __entry->ring_name =
> to_amdgpu_ring(job->base.sched)->name;
> >
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/amd-gfx/attachments/20180808/3adbbb44/attachment.html>
More information about the amd-gfx
mailing list