[PATCH v3] drm/amdgpu: Call amdgpu_device_unmap_mmio() if device is unplugged to prevent crash in GPU initialization failure

[Chen, Guchun]

[Public]

Reviewed-by: Guchun Chen <guchun.chen at amd.com>

Regards,
Guchun

-----Original Message-----
From: Shi, Leslie <Yuliang.Shi at amd.com> 
Sent: Friday, December 17, 2021 10:26 AM
To: Grodzovsky, Andrey <Andrey.Grodzovsky at amd.com>; Koenig, Christian <Christian.Koenig at amd.com>; Pan, Xinhui <Xinhui.Pan at amd.com>; Deucher, Alexander <Alexander.Deucher at amd.com>; amd-gfx at lists.freedesktop.org
Cc: Chen, Guchun <Guchun.Chen at amd.com>; Shi, Leslie <Yuliang.Shi at amd.com>
Subject: [PATCH v3] drm/amdgpu: Call amdgpu_device_unmap_mmio() if device is unplugged to prevent crash in GPU initialization failure

[Why]
In amdgpu_driver_load_kms, when amdgpu_device_init returns error during driver modprobe, it will start the error handle path immediately and call into amdgpu_device_unmap_mmio as well to release mapped VRAM. However, in the following release callback, driver stills visits the unmapped memory like vcn.inst[i].fw_shared_cpu_addr in vcn_v3_0_sw_fini. So a kernel crash occurs.

[How]
call amdgpu_device_unmap_mmio() if device is unplugged to prevent invalid memory address in
vcn_v3_0_sw_fini() when GPU initialization failure.

Signed-off-by: Leslie Shi <Yuliang.Shi at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index f31caec669e7..f6a47b927cfd 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3899,7 +3899,9 @@ void amdgpu_device_fini_hw(struct amdgpu_device *adev)
 
 	amdgpu_gart_dummy_page_fini(adev);
 
-	amdgpu_device_unmap_mmio(adev);
+	if (drm_dev_is_unplugged(adev_to_drm(adev)))
+		amdgpu_device_unmap_mmio(adev);
+
 }
 
 void amdgpu_device_fini_sw(struct amdgpu_device *adev)
--
2.25.1