| Message ID | 20250214210009.1994543-1-adrian.larumbe@collabora.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/2] drm/panthor: Replace sleep locks with spinlocks in fdinfo path | expand |
On Fri, 14 Feb 2025 20:55:20 +0000 Adrián Larumbe <adrian.larumbe@collabora.com> wrote: > Commit 0590c94c3596 ("drm/panthor: Fix race condition when gathering fdinfo > group samples") introduced an xarray lock to deal with potential > use-after-free errors when accessing groups fdinfo figures. However, this > toggles the kernel's atomic context status, so the next nested mutex lock > will raise a warning when the kernel is compiled with mutex debug options: > > CONFIG_DEBUG_RT_MUTEXES=y > CONFIG_DEBUG_MUTEXES=y > > Replace Panthor's group fdinfo data mutex with a guarded spinlock. > > Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com> > 0590c94c3596 ("drm/panthor: Fix race condition when gathering fdinfo group samples") My previous Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com> stands. > --- > drivers/gpu/drm/panthor/panthor_sched.c | 26 ++++++++++++------------- > 1 file changed, 12 insertions(+), 14 deletions(-) > > diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c > index 1a276db095ff..4d31d1967716 100644 > --- a/drivers/gpu/drm/panthor/panthor_sched.c > +++ b/drivers/gpu/drm/panthor/panthor_sched.c > @@ -9,6 +9,7 @@ > #include <drm/panthor_drm.h> > > #include <linux/build_bug.h> > +#include <linux/cleanup.h> > #include <linux/clk.h> > #include <linux/delay.h> > #include <linux/dma-mapping.h> > @@ -631,10 +632,10 @@ struct panthor_group { > struct panthor_gpu_usage data; > > /** > - * @lock: Mutex to govern concurrent access from drm file's fdinfo callback > - * and job post-completion processing function > + * @fdinfo.lock: Spinlock to govern concurrent access from drm file's fdinfo > + * callback and job post-completion processing function > */ > - struct mutex lock; > + spinlock_t lock; > > /** @fdinfo.kbo_sizes: Aggregate size of private kernel BO's held by the group. */ > size_t kbo_sizes; > @@ -910,8 +911,6 @@ static void group_release_work(struct work_struct *work) > release_work); > u32 i; > > - mutex_destroy(&group->fdinfo.lock); > - > for (i = 0; i < group->queue_count; i++) > group_free_queue(group, group->queues[i]); > > @@ -2861,12 +2860,12 @@ static void update_fdinfo_stats(struct panthor_job *job) > struct panthor_job_profiling_data *slots = queue->profiling.slots->kmap; > struct panthor_job_profiling_data *data = &slots[job->profiling.slot]; > > - mutex_lock(&group->fdinfo.lock); > - if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_CYCLES) > - fdinfo->cycles += data->cycles.after - data->cycles.before; > - if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_TIMESTAMP) > - fdinfo->time += data->time.after - data->time.before; > - mutex_unlock(&group->fdinfo.lock); > + scoped_guard(spinlock, &group->fdinfo.lock) { > + if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_CYCLES) > + fdinfo->cycles += data->cycles.after - data->cycles.before; > + if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_TIMESTAMP) > + fdinfo->time += data->time.after - data->time.before; > + } > } > > void panthor_fdinfo_gather_group_samples(struct panthor_file *pfile) > @@ -2880,12 +2879,11 @@ void panthor_fdinfo_gather_group_samples(struct panthor_file *pfile) > > xa_lock(&gpool->xa); > xa_for_each(&gpool->xa, i, group) { > - mutex_lock(&group->fdinfo.lock); > + guard(spinlock)(&group->fdinfo.lock); > pfile->stats.cycles += group->fdinfo.data.cycles; > pfile->stats.time += group->fdinfo.data.time; > group->fdinfo.data.cycles = 0; > group->fdinfo.data.time = 0; > - mutex_unlock(&group->fdinfo.lock); > } > xa_unlock(&gpool->xa); > } > @@ -3537,7 +3535,7 @@ int panthor_group_create(struct panthor_file *pfile, > mutex_unlock(&sched->reset.lock); > > add_group_kbo_sizes(group->ptdev, group); > - mutex_init(&group->fdinfo.lock); > + spin_lock_init(&group->fdinfo.lock); > > return gid; >
diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c index 1a276db095ff..4d31d1967716 100644 --- a/drivers/gpu/drm/panthor/panthor_sched.c +++ b/drivers/gpu/drm/panthor/panthor_sched.c @@ -9,6 +9,7 @@ #include <drm/panthor_drm.h> #include <linux/build_bug.h> +#include <linux/cleanup.h> #include <linux/clk.h> #include <linux/delay.h> #include <linux/dma-mapping.h> @@ -631,10 +632,10 @@ struct panthor_group { struct panthor_gpu_usage data; /** - * @lock: Mutex to govern concurrent access from drm file's fdinfo callback - * and job post-completion processing function + * @fdinfo.lock: Spinlock to govern concurrent access from drm file's fdinfo + * callback and job post-completion processing function */ - struct mutex lock; + spinlock_t lock; /** @fdinfo.kbo_sizes: Aggregate size of private kernel BO's held by the group. */ size_t kbo_sizes; @@ -910,8 +911,6 @@ static void group_release_work(struct work_struct *work) release_work); u32 i; - mutex_destroy(&group->fdinfo.lock); - for (i = 0; i < group->queue_count; i++) group_free_queue(group, group->queues[i]); @@ -2861,12 +2860,12 @@ static void update_fdinfo_stats(struct panthor_job *job) struct panthor_job_profiling_data *slots = queue->profiling.slots->kmap; struct panthor_job_profiling_data *data = &slots[job->profiling.slot]; - mutex_lock(&group->fdinfo.lock); - if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_CYCLES) - fdinfo->cycles += data->cycles.after - data->cycles.before; - if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_TIMESTAMP) - fdinfo->time += data->time.after - data->time.before; - mutex_unlock(&group->fdinfo.lock); + scoped_guard(spinlock, &group->fdinfo.lock) { + if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_CYCLES) + fdinfo->cycles += data->cycles.after - data->cycles.before; + if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_TIMESTAMP) + fdinfo->time += data->time.after - data->time.before; + } } void panthor_fdinfo_gather_group_samples(struct panthor_file *pfile) @@ -2880,12 +2879,11 @@ void panthor_fdinfo_gather_group_samples(struct panthor_file *pfile) xa_lock(&gpool->xa); xa_for_each(&gpool->xa, i, group) { - mutex_lock(&group->fdinfo.lock); + guard(spinlock)(&group->fdinfo.lock); pfile->stats.cycles += group->fdinfo.data.cycles; pfile->stats.time += group->fdinfo.data.time; group->fdinfo.data.cycles = 0; group->fdinfo.data.time = 0; - mutex_unlock(&group->fdinfo.lock); } xa_unlock(&gpool->xa); } @@ -3537,7 +3535,7 @@ int panthor_group_create(struct panthor_file *pfile, mutex_unlock(&sched->reset.lock); add_group_kbo_sizes(group->ptdev, group); - mutex_init(&group->fdinfo.lock); + spin_lock_init(&group->fdinfo.lock); return gid;
Commit 0590c94c3596 ("drm/panthor: Fix race condition when gathering fdinfo group samples") introduced an xarray lock to deal with potential use-after-free errors when accessing groups fdinfo figures. However, this toggles the kernel's atomic context status, so the next nested mutex lock will raise a warning when the kernel is compiled with mutex debug options: CONFIG_DEBUG_RT_MUTEXES=y CONFIG_DEBUG_MUTEXES=y Replace Panthor's group fdinfo data mutex with a guarded spinlock. Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com> 0590c94c3596 ("drm/panthor: Fix race condition when gathering fdinfo group samples") --- drivers/gpu/drm/panthor/panthor_sched.c | 26 ++++++++++++------------- 1 file changed, 12 insertions(+), 14 deletions(-)