[PATCH] drm/v3d: Disable interrupts before resetting the GPU

[Maíra Canal]

On 28/06/25 19:42, Maíra Canal wrote:
> Currently, an interrupt can be triggered during a GPU reset, which can
> lead to GPU hangs and NULL pointer dereference in an interrupt context
> as shown in the following trace:
> 
>   [  314.035040] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000c0
>   [  314.043822] Mem abort info:
>   [  314.046606]   ESR = 0x0000000096000005
>   [  314.050347]   EC = 0x25: DABT (current EL), IL = 32 bits
>   [  314.055651]   SET = 0, FnV = 0
>   [  314.058695]   EA = 0, S1PTW = 0
>   [  314.061826]   FSC = 0x05: level 1 translation fault
>   [  314.066694] Data abort info:
>   [  314.069564]   ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
>   [  314.075039]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
>   [  314.080080]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
>   [  314.085382] user pgtable: 4k pages, 39-bit VAs, pgdp=0000000102728000
>   [  314.091814] [00000000000000c0] pgd=0000000000000000, p4d=0000000000000000, pud=0000000000000000
>   [  314.100511] Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
>   [  314.106770] Modules linked in: v3d i2c_brcmstb vc4 snd_soc_hdmi_codec gpu_sched drm_shmem_helper drm_display_helper cec drm_dma_helper drm_kms_helper drm drm_panel_orientation_quirks snd_soc_core snd_compress snd_pcm_dmaengine snd_pcm snd_timer snd backlight
>   [  314.129654] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.12.25+rpt-rpi-v8 #1  Debian 1:6.12.25-1+rpt1
>   [  314.139388] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT)
>   [  314.145211] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>   [  314.152165] pc : v3d_irq+0xec/0x2e0 [v3d]
>   [  314.156187] lr : v3d_irq+0xe0/0x2e0 [v3d]
>   [  314.160198] sp : ffffffc080003ea0
>   [  314.163502] x29: ffffffc080003ea0 x28: ffffffec1f184980 x27: 021202b000000000
>   [  314.170633] x26: ffffffec1f17f630 x25: ffffff8101372000 x24: ffffffec1f17d9f0
>   [  314.177764] x23: 000000000000002a x22: 000000000000002a x21: ffffff8103252000
>   [  314.184895] x20: 0000000000000001 x19: 00000000deadbeef x18: 0000000000000000
>   [  314.192026] x17: ffffff94e51d2000 x16: ffffffec1dac3cb0 x15: c306000000000000
>   [  314.199156] x14: 0000000000000000 x13: b2fc982e03cc5168 x12: 0000000000000001
>   [  314.206286] x11: ffffff8103f8bcc0 x10: ffffffec1f196868 x9 : ffffffec1dac3874
>   [  314.213416] x8 : 0000000000000000 x7 : 0000000000042a3a x6 : ffffff810017a180
>   [  314.220547] x5 : ffffffec1ebad400 x4 : ffffffec1ebad320 x3 : 00000000000bebeb
>   [  314.227677] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
>   [  314.234807] Call trace:
>   [  314.237243]  v3d_irq+0xec/0x2e0 [v3d]
>   [  314.240906]  __handle_irq_event_percpu+0x58/0x218
>   [  314.245609]  handle_irq_event+0x54/0xb8
>   [  314.249439]  handle_fasteoi_irq+0xac/0x240
>   [  314.253527]  handle_irq_desc+0x48/0x68
>   [  314.257269]  generic_handle_domain_irq+0x24/0x38
>   [  314.261879]  gic_handle_irq+0x48/0xd8
>   [  314.265533]  call_on_irq_stack+0x24/0x58
>   [  314.269448]  do_interrupt_handler+0x88/0x98
>   [  314.273624]  el1_interrupt+0x34/0x68
>   [  314.277193]  el1h_64_irq_handler+0x18/0x28
>   [  314.281281]  el1h_64_irq+0x64/0x68
>   [  314.284673]  default_idle_call+0x3c/0x168
>   [  314.288675]  do_idle+0x1fc/0x230
>   [  314.291895]  cpu_startup_entry+0x3c/0x50
>   [  314.295810]  rest_init+0xe4/0xf0
>   [  314.299030]  start_kernel+0x5e8/0x790
>   [  314.302684]  __primary_switched+0x80/0x90
>   [  314.306691] Code: 940029eb 360ffc13 f9442ea0 52800001 (f9406017)
>   [  314.312775] ---[ end trace 0000000000000000 ]---
>   [  314.317384] Kernel panic - not syncing: Oops: Fatal exception in interrupt
>   [  314.324249] SMP: stopping secondary CPUs
>   [  314.328167] Kernel Offset: 0x2b9da00000 from 0xffffffc080000000
>   [  314.334076] PHYS_OFFSET: 0x0
>   [  314.336946] CPU features: 0x08,00002013,c0200000,0200421b
>   [  314.342337] Memory Limit: none
>   [  314.345382] ---[ end Kernel panic - not syncing: Oops: Fatal exception in interrupt ]---
> 
> Before resetting the GPU, it's necessary to disable all interrupts and
> deal with any interrupt handler still in-flight. Otherwise, the GPU might
> reset with jobs still running, or yet, an interrupt could be handled
> during the reset.
> 
> Cc: stable at vger.kernel.org
> Fixes: 57692c94dcbe ("drm/v3d: Introduce a new DRM driver for Broadcom V3D V3.x+")
> Signed-off-by: Maíra Canal <mcanal at igalia.com>

Applied to misc/kernel.git (drm-misc-fixes). Thanks for the review!

Best Regards,
- Maíra