drm/amdgpu: use spin_lock_irqsave to avoid deadlock by local interrupt

[ Upstream commit 2096b74b1da5ca418827b54ac4904493bd9de89c ]

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: 84ec374bd580 ("drm/amdgpu: create amdgpu_vkms (v4)")
Signed-off-by: Guchun Chen <guchun.chen@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Tested-by: Kelly Zytaruk <kelly.zytaruk@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c
index ac9a8cd..7d58bf4 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vkms.c
@@ -142,15 +142,16 @@ 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;
        }