| Message ID | 20240827074521.12828-2-pstanner@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/sched: Fix UB pointer dereference | expand |
Am 27.08.24 um 09:45 schrieb Philipp Stanner: > 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> Good catch, Reviewed-by: Christian König <christian.koenig@amd.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__); > return -ENOENT; > } >
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. Otherwise, Acked-by: Danilo Krummrich <dakr@kernel.org> > return -ENOENT; > } >
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; >> }
On Tue, 2024-08-27 at 11:00 +0200, Christian König wrote: > 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. Well, as we're at it I want to point out that the exact same mechanism occurs just a few lines below, from where I shamelessly copied it: if (unlikely(!credits)) { pr_err("*ERROR* %s: credits cannot be 0!\n", __func__); P. > > Thanks, > Christian. > > > > > Otherwise, > > > > Acked-by: Danilo Krummrich <dakr@kernel.org> > > > > > return -ENOENT; > > > } >
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__); return -ENOENT; }
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(-)