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authorFelix Kuehling <Felix.Kuehling@amd.com>2017-10-28 01:35:19 +0200
committerOded Gabbay <oded.gabbay@gmail.com>2017-10-28 01:35:19 +0200
commit9b56bb115460cee92a80bf85232b4b7da2f080e6 (patch)
treea2c2d9888ab7e38c5659af2e7e47798ac4c2af6b /drivers/gpu/drm/amd/amdkfd/kfd_events.c
parentdrm/amdkfd: Add SDMA trap src id to the KFD isr wanted list (diff)
downloadlinux-9b56bb115460cee92a80bf85232b4b7da2f080e6.tar.xz
linux-9b56bb115460cee92a80bf85232b4b7da2f080e6.zip
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/drm/amd/amdkfd/kfd_events.c')
-rw-r--r--drivers/gpu/drm/amd/amdkfd/kfd_events.c19
1 files changed, 15 insertions, 4 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);