I can confirm that the fault no longer occurs when the patch is implemented.

Thanks,
Kelly

-----Original Message-----
From: Chen, Guchun <[email protected]> 
Sent: January 10, 2022 12:14 AM
To: [email protected]; Deucher, Alexander 
<[email protected]>; Koenig, Christian <[email protected]>; Pan, 
Xinhui <[email protected]>; Zytaruk, Kelly <[email protected]>; Huang, 
Qiliang (Warden) <[email protected]>; Zhang, Bokun <[email protected]>
Cc: Chen, Guchun <[email protected]>
Subject: [PATCH] drm/amdgpu: use spin_lock_irqsave to avoid deadlock by local 
interrupt

This is observed in SRIOV case with virtual KMS as display.

_raw_spin_lock_irqsave+0x37/0x40
drm_handle_vblank+0x69/0x350 [drm]
? try_to_wake_up+0x432/0x5c0
? amdgpu_vkms_prepare_fb+0x1c0/0x1c0 [amdgpu]
drm_crtc_handle_vblank+0x17/0x20 [drm]
amdgpu_vkms_vblank_simulate+0x4d/0x80 [amdgpu]
__hrtimer_run_queues+0xfb/0x230
hrtimer_interrupt+0x109/0x220
__sysvec_apic_timer_interrupt+0x64/0xe0
asm_call_irq_on_stack+0x12/0x20

Fixes: ba5317109d0c("drm/amdgpu: create amdgpu_vkms (v4)")
Signed-off-by: Guchun Chen <[email protected]>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c
index 2dcc68e04e84..d99c8779b51e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c
@@ -144,15 +144,16 @@ static void amdgpu_vkms_crtc_atomic_disable(struct 
drm_crtc *crtc,  static void amdgpu_vkms_crtc_atomic_flush(struct drm_crtc 
*crtc,
                                          struct drm_atomic_state *state)
 {
+       unsigned long flags;
        if (crtc->state->event) {
-               spin_lock(&crtc->dev->event_lock);
+               spin_lock_irqsave(&crtc->dev->event_lock, flags);
 
                if (drm_crtc_vblank_get(crtc) != 0)
                        drm_crtc_send_vblank_event(crtc, crtc->state->event);
                else
                        drm_crtc_arm_vblank_event(crtc, crtc->state->event);
 
-               spin_unlock(&crtc->dev->event_lock);
+               spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
 
                crtc->state->event = NULL;
        }
--
2.17.1

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