[PATCH 1/2] drm/xe: Add a reason string to the devcoredump

Matthew Brost matthew.brost at intel.com
Thu Nov 21 05:36:52 UTC 2024


On Wed, Nov 20, 2024 at 07:38:30PM -0800, Matthew Brost wrote:
> On Wed, Nov 20, 2024 at 03:22:56PM -0800, John.C.Harrison at Intel.com wrote:
> > From: John Harrison <John.C.Harrison at Intel.com>
> > 
> > There are debug level prints giving more information about the cause
> > of the hang immediately before core dumps are created. However, not
> > everyone has debug level prints enabled or saves the dmesg log at all.
> > So include that information in the dump file itself. Also, at least
> > one of those prints included the pid as well as the process name. So
> > include that in the capture too.
> > 
> 
> This looks helpful.
> 
> A couple of nits below.
> 
> > Signed-off-by: John Harrison <John.C.Harrison at Intel.com>
> > ---
> >  drivers/gpu/drm/xe/xe_devcoredump.c       | 20 +++++++++++++++++---
> >  drivers/gpu/drm/xe/xe_devcoredump.h       |  5 +++--
> >  drivers/gpu/drm/xe/xe_devcoredump_types.h |  4 ++++
> >  drivers/gpu/drm/xe/xe_guc_submit.c        | 14 ++++++++++----
> >  4 files changed, 34 insertions(+), 9 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c b/drivers/gpu/drm/xe/xe_devcoredump.c
> > index 0e5edf14a241..b5aebe8fb06d 100644
> > --- a/drivers/gpu/drm/xe/xe_devcoredump.c
> > +++ b/drivers/gpu/drm/xe/xe_devcoredump.c
> > @@ -99,6 +99,7 @@ static ssize_t __xe_devcoredump_read(char *buffer, size_t count,
> >  	p = drm_coredump_printer(&iter);
> >  
> >  	drm_puts(&p, "**** Xe Device Coredump ****\n");
> > +	drm_printf(&p, "Reason: %s\n", ss->reason);
> >  	drm_puts(&p, "kernel: " UTS_RELEASE "\n");
> >  	drm_puts(&p, "module: " KBUILD_MODNAME "\n");
> >  
> > @@ -106,7 +107,7 @@ static ssize_t __xe_devcoredump_read(char *buffer, size_t count,
> >  	drm_printf(&p, "Snapshot time: %lld.%09ld\n", ts.tv_sec, ts.tv_nsec);
> >  	ts = ktime_to_timespec64(ss->boot_time);
> >  	drm_printf(&p, "Uptime: %lld.%09ld\n", ts.tv_sec, ts.tv_nsec);
> > -	drm_printf(&p, "Process: %s\n", ss->process_name);
> > +	drm_printf(&p, "Process: %s [%d]\n", ss->process_name, ss->pid);
> >  	xe_device_snapshot_print(xe, &p);
> >  
> >  	drm_printf(&p, "\n**** GT #%d ****\n", ss->gt->info.id);
> > @@ -138,6 +139,9 @@ static void xe_devcoredump_snapshot_free(struct xe_devcoredump_snapshot *ss)
> >  {
> >  	int i;
> >  
> > +	kvfree(ss->reason);
> 
> Do we need kvalloc / kvfree here? Seems like this would be small in size.
> 
> > +	ss->reason = NULL;
> > +
> >  	xe_guc_log_snapshot_free(ss->guc.log);
> >  	ss->guc.log = NULL;
> >  
> > @@ -253,8 +257,11 @@ static void devcoredump_snapshot(struct xe_devcoredump *coredump,
> >  	ss->snapshot_time = ktime_get_real();
> >  	ss->boot_time = ktime_get_boottime();
> >  
> > -	if (q->vm && q->vm->xef)
> > +	if (q->vm && q->vm->xef) {
> >  		process_name = q->vm->xef->process_name;
> > +		ss->pid = q->vm->xef->pid;
> > +	}
> > +
> >  	strscpy(ss->process_name, process_name);
> >  
> >  	ss->gt = q->gt;
> > @@ -297,10 +304,12 @@ static void devcoredump_snapshot(struct xe_devcoredump *coredump,
> >   * gt_reset. It is skipped if we still have the core dump device available
> >   * with the information of the 'first' snapshot.
> >   */
> 
> Seems like kernel doc should be updated.
> 
> > -void xe_devcoredump(struct xe_exec_queue *q, struct xe_sched_job *job)
> > +__printf(3, 4)
> > +void xe_devcoredump(struct xe_exec_queue *q, struct xe_sched_job *job, const char *fmt, ...)
> >  {
> >  	struct xe_device *xe = gt_to_xe(q->gt);
> >  	struct xe_devcoredump *coredump = &xe->devcoredump;
> > +	va_list varg;
> >  
> >  	if (coredump->captured) {
> >  		drm_dbg(&xe->drm, "Multiple hangs are occurring, but only the first snapshot was taken\n");
> > @@ -308,6 +317,11 @@ void xe_devcoredump(struct xe_exec_queue *q, struct xe_sched_job *job)
> >  	}
> >  
> >  	coredump->captured = true;
> > +
> > +	va_start(varg, fmt);
> > +	coredump->snapshot.reason = kvasprintf(GFP_KERNEL, fmt, varg);
> 
> See above. Off the top my head idk if there is a non-kv* version of this
> function but if there is, maybe use that.

Ok, scratch this comment. I do see these functions defined:

__printf(2, 3) __malloc char *kasprintf(gfp_t gfp, const char *fmt, ...);
__printf(2, 0) __malloc char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);

The former call doesn't work here as va_start is only safe to call once
in a call chain [1]. The former internally needs to call va_start again.
Unsure why this seemly equivalent functions have different signatures
but I think your usage here is correct.

Matt

[1] https://stackoverflow.com/questions/59608636/can-we-call-va-start-twice-without-calling-va-end-in-between

> 
> Nits aside, LGTM:
> Reviewed-by: Matthew Brost <matthew.brost at intel.com>
> 
> > +	va_end(varg);
> > +
> >  	devcoredump_snapshot(coredump, q, job);
> >  
> >  	drm_info(&xe->drm, "Xe device coredump has been created\n");
> > diff --git a/drivers/gpu/drm/xe/xe_devcoredump.h b/drivers/gpu/drm/xe/xe_devcoredump.h
> > index c04a534e3384..6a17e6d60102 100644
> > --- a/drivers/gpu/drm/xe/xe_devcoredump.h
> > +++ b/drivers/gpu/drm/xe/xe_devcoredump.h
> > @@ -14,11 +14,12 @@ struct xe_exec_queue;
> >  struct xe_sched_job;
> >  
> >  #ifdef CONFIG_DEV_COREDUMP
> > -void xe_devcoredump(struct xe_exec_queue *q, struct xe_sched_job *job);
> > +void xe_devcoredump(struct xe_exec_queue *q, struct xe_sched_job *job, const char *fmt, ...);
> >  int xe_devcoredump_init(struct xe_device *xe);
> >  #else
> >  static inline void xe_devcoredump(struct xe_exec_queue *q,
> > -				  struct xe_sched_job *job)
> > +				  struct xe_sched_job *job,
> > +				  const char *fmt, ...)
> >  {
> >  }
> >  
> > diff --git a/drivers/gpu/drm/xe/xe_devcoredump_types.h b/drivers/gpu/drm/xe/xe_devcoredump_types.h
> > index be4d59ea9ac8..e6234e887102 100644
> > --- a/drivers/gpu/drm/xe/xe_devcoredump_types.h
> > +++ b/drivers/gpu/drm/xe/xe_devcoredump_types.h
> > @@ -28,6 +28,10 @@ struct xe_devcoredump_snapshot {
> >  	ktime_t boot_time;
> >  	/** @process_name: Name of process that triggered this gpu hang */
> >  	char process_name[TASK_COMM_LEN];
> > +	/** @pid: Process id of process that triggered this gpu hang */
> > +	pid_t pid;
> > +	/** @reason: The reason the coredump was triggered */
> > +	char *reason;
> >  
> >  	/** @gt: Affected GT, used by forcewake for delayed capture */
> >  	struct xe_gt *gt;
> > diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
> > index e132294fde51..7d0e7cb977ad 100644
> > --- a/drivers/gpu/drm/xe/xe_guc_submit.c
> > +++ b/drivers/gpu/drm/xe/xe_guc_submit.c
> > @@ -898,7 +898,8 @@ static void xe_guc_exec_queue_lr_cleanup(struct work_struct *w)
> >  		if (!ret) {
> >  			xe_gt_warn(q->gt, "Schedule disable failed to respond, guc_id=%d\n",
> >  				   q->guc->id);
> > -			xe_devcoredump(q, NULL);
> > +			xe_devcoredump(q, NULL, "Schedule disable failed to respond, guc_id=%d\n",
> > +				       q->guc->id);
> >  			xe_sched_submission_start(sched);
> >  			xe_gt_reset_async(q->gt);
> >  			return;
> > @@ -906,7 +907,7 @@ static void xe_guc_exec_queue_lr_cleanup(struct work_struct *w)
> >  	}
> >  
> >  	if (!exec_queue_killed(q) && !xe_lrc_ring_is_idle(q->lrc[0]))
> > -		xe_devcoredump(q, NULL);
> > +		xe_devcoredump(q, NULL, "LR job cleanup, guc_id=%d", q->guc->id);
> >  
> >  	xe_sched_submission_start(sched);
> >  }
> > @@ -1132,7 +1133,9 @@ guc_exec_queue_timedout_job(struct drm_sched_job *drm_job)
> >  				xe_gt_warn(guc_to_gt(guc),
> >  					   "Schedule disable failed to respond, guc_id=%d",
> >  					   q->guc->id);
> > -			xe_devcoredump(q, job);
> > +			xe_devcoredump(q, job,
> > +				       "Schedule disable failed to respond, guc_id=%d, ret=%d, guc_read=%d",
> > +				       q->guc->id, ret, xe_guc_read_stopped(guc));
> >  			set_exec_queue_extra_ref(q);
> >  			xe_exec_queue_get(q);	/* GT reset owns this */
> >  			set_exec_queue_banned(q);
> > @@ -1162,7 +1165,10 @@ guc_exec_queue_timedout_job(struct drm_sched_job *drm_job)
> >  	trace_xe_sched_job_timedout(job);
> >  
> >  	if (!exec_queue_killed(q))
> > -		xe_devcoredump(q, job);
> > +		xe_devcoredump(q, job,
> > +			       "Timedout job - seqno=%u, lrc_seqno=%u, guc_id=%d, flags=0x%lx",
> > +			       xe_sched_job_seqno(job), xe_sched_job_lrc_seqno(job),
> > +			       q->guc->id, q->flags);
> >  
> >  	/*
> >  	 * Kernel jobs should never fail, nor should VM jobs if they do
> > -- 
> > 2.47.0
> > 


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