Am 27.08.24 um 10:39 schrieb Danilo Krummrich:
On 8/27/24 9:45 AM, Philipp Stanner wrote:
In drm_sched_job_init(), commit 56e449603f0a ("drm/sched: Convert the GPU scheduler to variable number of run-queues") implemented a call to drm_err(), which uses the job's scheduler pointer as a parameter. job->sched, however, is not yet valid as it gets set by drm_sched_job_arm(), which is always called after drm_sched_job_init().
Since the scheduler code has no control over how the API-User has allocated or set 'job', the pointer's dereference is undefined behavior.
Fix the UB by replacing drm_err() with pr_err().
Cc: stable@vger.kernel.org # 6.7+ Fixes: 56e449603f0a ("drm/sched: Convert the GPU scheduler to variable number of run-queues") Reported-by: Danilo Krummrich dakr@redhat.com Closes: https://lore.kernel.org/lkml/20231108022716.15250-1-dakr@redhat.com/ Signed-off-by: Philipp Stanner pstanner@redhat.com
drivers/gpu/drm/scheduler/sched_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c index 7e90c9f95611..356c30fa24a8 100644 --- a/drivers/gpu/drm/scheduler/sched_main.c +++ b/drivers/gpu/drm/scheduler/sched_main.c @@ -797,7 +797,7 @@ int drm_sched_job_init(struct drm_sched_job *job, * or worse--a blank screen--leave a trail in the * logs, so this can be debugged easier. */ - drm_err(job->sched, "%s: entity has no rq!\n", __func__); + pr_err("*ERROR* %s: entity has no rq!\n", __func__);
I don't think the "*ERROR*" string is necessary, it's pr_err() already.
Good point. I will remove that and also add a comment why drm_err won't work here before pushing it to drm-misc-fixes.
Thanks, Christian.
Otherwise,
Acked-by: Danilo Krummrich dakr@kernel.org
return -ENOENT; }