The patch below does not apply to the 6.0-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
Possible dependencies:
f9e694964503 ("drm/amdgpu: workaround for TLB seq race")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From f9e69496450352fa0504fd5a8fd9134b31116558 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@xxxxxxx>
Date: Wed, 2 Nov 2022 14:55:13 +0100
Subject: [PATCH] drm/amdgpu: workaround for TLB seq race
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
It can happen that we query the sequence value before the callback
had a chance to run.
Workaround that by grabbing the fence lock and releasing it again.
Should be replaced by hw handling soon.
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
CC: stable@xxxxxxxxxxxxxxx # 5.19+
Fixes: 5255e146c99a6 ("drm/amdgpu: rework TLB flushing")
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2113
Acked-by: Alex Deucher <alexander.deucher@xxxxxxx>
Acked-by: Philip Yang <Philip.Yang@xxxxxxx>
Tested-by: Stefan Springer <stefanspr94@xxxxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index 83acb7bd80fe..1d31771b4230 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -492,6 +492,21 @@ void amdgpu_debugfs_vm_bo_info(struct amdgpu_vm *vm, struct seq_file *m);
*/
static inline uint64_t amdgpu_vm_tlb_seq(struct amdgpu_vm *vm)
{
+ unsigned long flags;
+ spinlock_t *lock;
+
+ /*
+ * Workaround to stop racing between the fence signaling and handling
+ * the cb. The lock is static after initially setting it up, just make
+ * sure that the dma_fence structure isn't freed up.
+ */
+ rcu_read_lock();
+ lock = vm->last_tlb_flush->lock;
+ rcu_read_unlock();
+
+ spin_lock_irqsave(lock, flags);
+ spin_unlock_irqrestore(lock, flags);
+
return atomic64_read(&vm->tlb_seq);
}
