diff options
| author | Felix Kuehling <Felix.Kuehling@amd.com> | 2017-10-27 19:35:19 -0400 |
|---|---|---|
| committer | Oded Gabbay <oded.gabbay@gmail.com> | 2017-10-27 19:35:19 -0400 |
| commit | 9b56bb115460cee92a80bf85232b4b7da2f080e6 (patch) | |
| tree | a2c2d9888ab7e38c5659af2e7e47798ac4c2af6b /drivers/gpu | |
| parent | 66b783b4465de05ce6b370b1ae97e95b0fc14a34 (diff) | |
drm/amdkfd: Don't dereference kfd_process.mm
The kfd_process doesn't own a reference to the mm_struct, so it can
disappear without warning even while the kfd_process still exists.
Therefore, avoid dereferencing the kfd_process.mm pointer and make
it opaque. Use get_task_mm to get a temporary reference to the mm
when it's needed.
v2: removed unnecessary WARN_ON
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/amd/amdkfd/kfd_events.c | 19 | ||||
| -rw-r--r-- | drivers/gpu/drm/amd/amdkfd/kfd_priv.h | 7 | ||||
| -rw-r--r-- | drivers/gpu/drm/amd/amdkfd/kfd_process.c | 1 |
3 files changed, 21 insertions, 6 deletions
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_events.c index 944abfad39c1..61ce5476c055 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_events.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_events.c @@ -24,8 +24,8 @@ #include <linux/slab.h> #include <linux/types.h> #include <linux/sched/signal.h> +#include <linux/sched/mm.h> #include <linux/uaccess.h> -#include <linux/mm.h> #include <linux/mman.h> #include <linux/memory.h> #include "kfd_priv.h" @@ -904,14 +904,24 @@ void kfd_signal_iommu_event(struct kfd_dev *dev, unsigned int pasid, * running so the lookup function returns a locked process. */ struct kfd_process *p = kfd_lookup_process_by_pasid(pasid); + struct mm_struct *mm; if (!p) return; /* Presumably process exited. */ + /* Take a safe reference to the mm_struct, which may otherwise + * disappear even while the kfd_process is still referenced. + */ + mm = get_task_mm(p->lead_thread); + if (!mm) { + mutex_unlock(&p->mutex); + return; /* Process is exiting */ + } + memset(&memory_exception_data, 0, sizeof(memory_exception_data)); - down_read(&p->mm->mmap_sem); - vma = find_vma(p->mm, address); + down_read(&mm->mmap_sem); + vma = find_vma(mm, address); memory_exception_data.gpu_id = dev->id; memory_exception_data.va = address; @@ -937,7 +947,8 @@ void kfd_signal_iommu_event(struct kfd_dev *dev, unsigned int pasid, } } - up_read(&p->mm->mmap_sem); + up_read(&mm->mmap_sem); + mmput(mm); mutex_lock(&p->event_mutex); diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h index 7d86ec9790d3..1a483a7ecd4e 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h +++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h @@ -494,7 +494,12 @@ struct kfd_process { */ struct hlist_node kfd_processes; - struct mm_struct *mm; + /* + * Opaque pointer to mm_struct. We don't hold a reference to + * it so it should never be dereferenced from here. This is + * only used for looking up processes by their mm. + */ + void *mm; struct mutex mutex; diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c index 3ccb3b53216e..695fa2ae8e5b 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c @@ -200,7 +200,6 @@ static void kfd_process_destroy_delayed(struct rcu_head *rcu) struct kfd_process *p; p = container_of(rcu, struct kfd_process, rcu); - WARN_ON(atomic_read(&p->mm->mm_count) <= 0); mmdrop(p->mm); |