1 files changed, 25 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gv11b/fb_gv11b.c b/drivers/gpu/nvgpu/gv11b/fb_gv11b.c
index ce8f5669..bba7e66c 100644
--- a/drivers/gpu/nvgpu/gv11b/fb_gv11b.c
+++ b/drivers/gpu/nvgpu/gv11b/fb_gv11b.c
@@ -935,12 +935,37 @@ static void gv11b_fb_handle_mmu_fault_common(struct gk20a *g,
                                 id = mmfault->chid;
                                 id_type = ID_TYPE_CHANNEL;
                         }
+                        if (mmfault->refch->mmu_nack_handled) {
+                                /* We have already recovered for the same
+                                 * context, skip doing another recovery.
+                                 */
+                                mmfault->refch->mmu_nack_handled = false;
+                                /*
+                                 * Recovery path can be entered twice for the
+                                 * same error in case of mmu nack. If mmu
+                                 * nack interrupt is handled before mmu fault
+                                 * then channel reference is increased to avoid
+                                 * closing the channel by userspace. Decrement
+                                 * channel reference.
+                                 */
+                                gk20a_channel_put(mmfault->refch);
+                                /* refch in mmfault is assigned at the time
+                                 * of copying fault info from snap reg or bar2
+                                 * fault buf.
+                                 */
+                                gk20a_channel_put(mmfault->refch);
+                                return;
+                        }
                 } else {
                         id_type = ID_TYPE_UNKNOWN;
                 }
                 if (mmfault->faulted_engine != FIFO_INVAL_ENGINE_ID)
                         act_eng_bitmask = BIT(mmfault->faulted_engine);
 
+                /* Indicate recovery is handled if mmu fault is a result of
+                 * mmu nack.
+                 */
+                mmfault->refch->mmu_nack_handled = true;
                 g->ops.fifo.teardown_ch_tsg(g, act_eng_bitmask,
                         id, id_type, RC_TYPE_MMU_FAULT, mmfault);
         } else {