@@ -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") Reviewed-by: Liviu Dudau <liviu.dudau@arm.com> Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com> --- drivers/gpu/drm/panthor/panthor_sched.c | 26 ++++++++++++------------- 1 file changed, 12 insertions(+), 14 deletions(-)