`vc4_atomic_commit_tail` kernel warning log flood on CM4S
Open
Nobody has claimed this yet.
Assessment
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Newbie friendliness
- 25/100
- Issue type
- Bug
- Clarity
- Mostly clear
- Activity status
- Stale
- Tech stack
- c, linux
- Domain
- computer-graphics, operating-systems
Research direction
Reproduce the warning flood on a CM4S using Bookworm and kernel 6.12.20, then inspect drivers/gpu/drm/vc4/vc4_kms.c around vc4_atomic_commit_tail and the reported lines 453, 454, 507, and 508. Compare the resulting dmesg output with the issue logs; done means the underlying warnings are addressed and the repeated log flood no longer occurs.
Written by the indexing model from the issue text.
Description
Describe the bug
On a CM4S, using kernel v6.12.20, I'm experiencing a vc4_atomic_commit_tail kernel warning log flood.
Steps to reproduce the behaviour
- Create a recent Bookworm OS with pi-gen
- Boot on a CM4S
- Examine the output of
dmesg
Device (s)
Other
System
$ vcgencmd version
Mar 19 2025 18:24:21
Copyright (c) 2012 Broadcom
version ca6e8171a80ea46924ffaa629250bfb482f3a02c (clean) (release) (start)
$ uname -a
Linux comfilepi 6.12.20+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.12.20-1+rpt1~bpo12+1 (2025-03-19) aarch64 GNU/Linux
Logs
dmesg:
[ 219.965430] ------------[ cut here ]------------
[ 219.965448] WARNING: CPU: 0 PID: 87 at drivers/gpu/drm/vc4/vc4_kms.c:507 vc4_atomic_commit_tail+0x900/0x920 [vc4]
[ 219.965523] Modules linked in: snd_seq_dummy snd_hrtimer snd_seq snd_seq_device rfkill binfmt_misc rpi_hevc_dec bcm2835_codec(C) bcm2835_isp(C) bcm2835_v4l2(C) bcm2835_mmal_vchiq(C) vc_sm_cma(C) v4l2_mem2mem videobuf2_dma_contig videobuf2_vmalloc joydev videobuf2_memops videobuf2_v4l2 raspberrypi_hwmon videodev videobuf2_common mc snd_bcm2835(C) raspberrypi_gpiomem nvmem_rmem uio_pdrv_genirq uio i2c_dev ledtrig_pattern fuse dm_mod ip_tables x_tables ipv6 rtc_ds1307 regmap_i2c vc4 v3d gpu_sched snd_soc_hdmi_codec drm_shmem_helper drm_display_helper cec drm_dma_helper drm_kms_helper i2c_brcmstb drm drm_panel_orientation_quirks i2c_bcm2835 snd_soc_core snd_compress snd_pcm_dmaengine snd_pcm snd_timer snd backlight
[ 219.965789] CPU: 0 UID: 0 PID: 87 Comm: kworker/u20:2 Tainted: G WC 6.12.20+rpt-rpi-v8 #1 Debian 1:6.12.20-1+rpt1~bpo12+1
[ 219.965808] Tainted: [W]=WARN, [C]=CRAP
[ 219.965814] Hardware name: Raspberry Pi Compute Module 4S Rev 1.0 (DT)
[ 219.965823] Workqueue: events_unbound commit_work [drm_kms_helper]
[ 219.965904] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 219.965917] pc : vc4_atomic_commit_tail+0x900/0x920 [vc4]
[ 219.965975] lr : vc4_atomic_commit_tail+0x1f4/0x920 [vc4]
[ 219.966030] sp : ffffffc08113bd00
[ 219.966036] x29: ffffffc08113bd00 x28: 0000000000000000 x27: 0000000000000000
[ 219.966057] x26: ffffff8041210080 x25: 0000000000000038 x24: ffffff8044fd5300
[ 219.966078] x23: ffffff8041210080 x22: ffffff80410beb00 x21: ffffff804558a000
[ 219.966098] x20: 0000000000000006 x19: 0000000001fb00f8 x18: 0000000000000000
[ 219.966118] x17: 0000000000000000 x16: ffffffe614a2d010 x15: 00000055b2b10a50
[ 219.966139] x14: 0000000000000000 x13: 000000000ee6b280 x12: 0000000480000008
[ 219.966159] x11: ffffffc08002d000 x10: 0000000000001a40 x9 : ffffffe614a23c74
[ 219.966179] x8 : 0000000000000040 x7 : 000000000ee6b280 x6 : 0ee6b28000000004
[ 219.966200] x5 : 0000000000000001 x4 : 0000000000000000 x3 : 0000000000000000
[ 219.966219] x2 : ffffff804592a100 x1 : ffffff804592a100 x0 : 00000000ffffffea
[ 219.966239] Call trace:
[ 219.966245] vc4_atomic_commit_tail+0x900/0x920 [vc4]
[ 219.966301] commit_tail+0xac/0x1a0 [drm_kms_helper]
[ 219.966377] commit_work+0x1c/0x30 [drm_kms_helper]
[ 219.966450] process_one_work+0x158/0x3d0
[ 219.966469] worker_thread+0x2d8/0x3e8
[ 219.966483] kthread+0x11c/0x128
[ 219.966494] ret_from_fork+0x10/0x20
[ 219.966508] ---[ end trace 0000000000000000 ]---
[ 219.966645] ------------[ cut here ]------------
[ 219.966655] WARNING: CPU: 0 PID: 87 at drivers/gpu/drm/vc4/vc4_kms.c:508 vc4_atomic_commit_tail+0x864/0x920 [vc4]
[ 219.966722] Modules linked in: snd_seq_dummy snd_hrtimer snd_seq snd_seq_device rfkill binfmt_misc rpi_hevc_dec bcm2835_codec(C) bcm2835_isp(C) bcm2835_v4l2(C) bcm2835_mmal_vchiq(C) vc_sm_cma(C) v4l2_mem2mem videobuf2_dma_contig videobuf2_vmalloc joydev videobuf2_memops videobuf2_v4l2 raspberrypi_hwmon videodev videobuf2_common mc snd_bcm2835(C) raspberrypi_gpiomem nvmem_rmem uio_pdrv_genirq uio i2c_dev ledtrig_pattern fuse dm_mod ip_tables x_tables ipv6 rtc_ds1307 regmap_i2c vc4 v3d gpu_sched snd_soc_hdmi_codec drm_shmem_helper drm_display_helper cec drm_dma_helper drm_kms_helper i2c_brcmstb drm drm_panel_orientation_quirks i2c_bcm2835 snd_soc_core snd_compress snd_pcm_dmaengine snd_pcm snd_timer snd backlight
[ 219.966981] CPU: 0 UID: 0 PID: 87 Comm: kworker/u20:2 Tainted: G WC 6.12.20+rpt-rpi-v8 #1 Debian 1:6.12.20-1+rpt1~bpo12+1
[ 219.966998] Tainted: [W]=WARN, [C]=CRAP
[ 219.967004] Hardware name: Raspberry Pi Compute Module 4S Rev 1.0 (DT)
[ 219.967012] Workqueue: events_unbound commit_work [drm_kms_helper]
[ 219.967094] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 219.967106] pc : vc4_atomic_commit_tail+0x864/0x920 [vc4]
[ 219.967165] lr : vc4_atomic_commit_tail+0x204/0x920 [vc4]
[ 219.967220] sp : ffffffc08113bd00
[ 219.967226] x29: ffffffc08113bd00 x28: 0000000000000000 x27: 0000000000000000
[ 219.967247] x26: ffffff8041210080 x25: 0000000000000038 x24: ffffff8044fd5300
[ 219.967268] x23: ffffff8041210080 x22: ffffff80410beb00 x21: ffffff804558a000
[ 219.967288] x20: 0000000000000006 x19: 0000000001fb00f8 x18: 0000000000000000
[ 219.967309] x17: 0000000000000000 x16: ffffffe614a2d010 x15: 00000055b2b10a50
[ 219.967329] x14: 0000000000000000 x13: 000000000ee6b280 x12: 0000000480000008
[ 219.967350] x11: ffffffc08002d000 x10: 0000000000001a40 x9 : ffffffe614a23c74
[ 219.967370] x8 : 0000000000000040 x7 : 000000000ee6b280 x6 : 0ee6b28000000004
[ 219.967390] x5 : 0000000000000001 x4 : 0000000000000000 x3 : 0000000000000000
[ 219.967409] x2 : ffffff804592a100 x1 : ffffff804592a100 x0 : 00000000ffffffea
[ 219.967429] Call trace:
[ 219.967435] vc4_atomic_commit_tail+0x864/0x920 [vc4]
[ 219.967492] commit_tail+0xac/0x1a0 [drm_kms_helper]
[ 219.967568] commit_work+0x1c/0x30 [drm_kms_helper]
[ 219.967641] process_one_work+0x158/0x3d0
[ 219.967657] worker_thread+0x2d8/0x3e8
[ 219.967671] kthread+0x11c/0x128
[ 219.967684] ret_from_fork+0x10/0x20
[ 219.967697] ---[ end trace 0000000000000000 ]---
[ 220.958520] ------------[ cut here ]------------
[ 220.958543] WARNING: CPU: 3 PID: 87 at drivers/gpu/drm/vc4/vc4_kms.c:453 vc4_atomic_commit_tail+0x8f8/0x920 [vc4]
[ 220.958630] Modules linked in: snd_seq_dummy snd_hrtimer snd_seq snd_seq_device rfkill binfmt_misc rpi_hevc_dec bcm2835_codec(C) bcm2835_isp(C) bcm2835_v4l2(C) bcm2835_mmal_vchiq(C) vc_sm_cma(C) v4l2_mem2mem videobuf2_dma_contig videobuf2_vmalloc joydev videobuf2_memops videobuf2_v4l2 raspberrypi_hwmon videodev videobuf2_common mc snd_bcm2835(C) raspberrypi_gpiomem nvmem_rmem uio_pdrv_genirq uio i2c_dev ledtrig_pattern fuse dm_mod ip_tables x_tables ipv6 rtc_ds1307 regmap_i2c vc4 v3d gpu_sched snd_soc_hdmi_codec drm_shmem_helper drm_display_helper cec drm_dma_helper drm_kms_helper i2c_brcmstb drm drm_panel_orientation_quirks i2c_bcm2835 snd_soc_core snd_compress snd_pcm_dmaengine snd_pcm snd_timer snd backlight
[ 220.958903] CPU: 3 UID: 0 PID: 87 Comm: kworker/u20:2 Tainted: G WC 6.12.20+rpt-rpi-v8 #1 Debian 1:6.12.20-1+rpt1~bpo12+1
[ 220.958922] Tainted: [W]=WARN, [C]=CRAP
[ 220.958928] Hardware name: Raspberry Pi Compute Module 4S Rev 1.0 (DT)
[ 220.958937] Workqueue: events_unbound commit_work [drm_kms_helper]
[ 220.959029] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 220.959041] pc : vc4_atomic_commit_tail+0x8f8/0x920 [vc4]
[ 220.959100] lr : vc4_atomic_commit_tail+0x394/0x920 [vc4]
[ 220.959156] sp : ffffffc08113bd00
[ 220.959162] x29: ffffffc08113bd00 x28: 0000000000000000 x27: 0000000000000000
[ 220.959184] x26: ffffff80410beb70 x25: ffffff80410beb00 x24: ffffff8044fd53c0
[ 220.959205] x23: ffffff8041210080 x22: ffffff80410be680 x21: ffffff804558a000
[ 220.959225] x20: 000000001dcd6500 x19: ffffff80410be200 x18: 0000000000000000
[ 220.959246] x17: 0000000000000000 x16: ffffffe614a2d010 x15: 0000000000000000
[ 220.959267] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000001
[ 220.959286] x11: ffffff807fbbecc0 x10: 0000000000001a40 x9 : ffffffe614a23c74
[ 220.959307] x8 : ffffffe60456b000 x7 : 0000000000000000 x6 : ffffff804592a100
[ 220.959327] x5 : ffffff804592a100 x4 : 0000000000000000 x3 : 0000000000000000
[ 220.959346] x2 : ffffff804592a100 x1 : ffffff804592a100 x0 : 00000000ffffffea
[ 220.959366] Call trace:
[ 220.959374] vc4_atomic_commit_tail+0x8f8/0x920 [vc4]
[ 220.959431] commit_tail+0xac/0x1a0 [drm_kms_helper]
[ 220.959506] commit_work+0x1c/0x30 [drm_kms_helper]
[ 220.959580] process_one_work+0x158/0x3d0
[ 220.959599] worker_thread+0x2d8/0x3e8
[ 220.959613] kthread+0x11c/0x128
[ 220.959626] ret_from_fork+0x10/0x20
[ 220.959640] ---[ end trace 0000000000000000 ]---
[ 220.959695] ------------[ cut here ]------------
[ 220.959700] WARNING: CPU: 3 PID: 87 at drivers/gpu/drm/vc4/vc4_kms.c:454 vc4_atomic_commit_tail+0x3a8/0x920 [vc4]
[ 220.959763] Modules linked in: snd_seq_dummy snd_hrtimer snd_seq snd_seq_device rfkill binfmt_misc rpi_hevc_dec bcm2835_codec(C) bcm2835_isp(C) bcm2835_v4l2(C) bcm2835_mmal_vchiq(C) vc_sm_cma(C) v4l2_mem2mem videobuf2_dma_contig videobuf2_vmalloc joydev videobuf2_memops videobuf2_v4l2 raspberrypi_hwmon videodev videobuf2_common mc snd_bcm2835(C) raspberrypi_gpiomem nvmem_rmem uio_pdrv_genirq uio i2c_dev ledtrig_pattern fuse dm_mod ip_tables x_tables ipv6 rtc_ds1307 regmap_i2c vc4 v3d gpu_sched snd_soc_hdmi_codec drm_shmem_helper drm_display_helper cec drm_dma_helper drm_kms_helper i2c_brcmstb drm drm_panel_orientation_quirks i2c_bcm2835 snd_soc_core snd_compress snd_pcm_dmaengine snd_pcm snd_timer snd backlight
[ 220.960018] CPU: 3 UID: 0 PID: 87 Comm: kworker/u20:2 Tainted: G WC 6.12.20+rpt-rpi-v8 #1 Debian 1:6.12.20-1+rpt1~bpo12+1
[ 220.960034] Tainted: [W]=WARN, [C]=CRAP
[ 220.960040] Hardware name: Raspberry Pi Compute Module 4S Rev 1.0 (DT)
[ 220.960047] Workqueue: events_unbound commit_work [drm_kms_helper]
[ 220.960127] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 220.960139] pc : vc4_atomic_commit_tail+0x3a8/0x920 [vc4]
[ 220.960196] lr : vc4_atomic_commit_tail+0x3a4/0x920 [vc4]
[ 220.960251] sp : ffffffc08113bd00
[ 220.960257] x29: ffffffc08113bd00 x28: 0000000000000000 x27: 0000000000000000
[ 220.960277] x26: ffffff80410beb70 x25: ffffff80410beb00 x24: ffffff8044fd53c0
[ 220.960298] x23: ffffff8041210080 x22: ffffff80410be680 x21: ffffff804558a000
[ 220.960318] x20: 000000001dcd6500 x19: ffffff80410be200 x18: 0000000000000000
[ 220.960339] x17: 0000000000000000 x16: ffffffe614a2d010 x15: 0000000000000000
[ 220.960360] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000001
[ 220.960380] x11: ffffff807fbbecc0 x10: 0000000000001a40 x9 : ffffffe614a23c74
[ 220.960401] x8 : ffffffe60456b000 x7 : 0000000000000000 x6 : ffffff804592a100
[ 220.960421] x5 : ffffff804592a100 x4 : 0000000000000000 x3 : 0000000000000000
[ 220.960440] x2 : ffffff804592a100 x1 : ffffff804592a100 x0 : 00000000ffffffea
[ 220.960460] Call trace:
[ 220.960466] vc4_atomic_commit_tail+0x3a8/0x920 [vc4]
[ 220.960521] commit_tail+0xac/0x1a0 [drm_kms_helper]
[ 220.960596] commit_work+0x1c/0x30 [drm_kms_helper]
[ 220.960670] process_one_work+0x158/0x3d0
[ 220.960685] worker_thread+0x2d8/0x3e8
[ 220.960698] kthread+0x11c/0x128
[ 220.960709] ret_from_fork+0x10/0x20
[ 220.960721] ---[ end trace 0000000000000000 ]---
[ 220.964396] ------------[ cut here ]------------
[ 220.964411] WARNING: CPU: 3 PID: 87 at drivers/gpu/drm/vc4/vc4_kms.c:507 vc4_atomic_commit_tail+0x900/0x920 [vc4]
[ 220.964482] Modules linked in: snd_seq_dummy snd_hrtimer snd_seq snd_seq_device rfkill binfmt_misc rpi_hevc_dec bcm2835_codec(C) bcm2835_isp(C) bcm2835_v4l2(C) bcm2835_mmal_vchiq(C) vc_sm_cma(C) v4l2_mem2mem videobuf2_dma_contig videobuf2_vmalloc joydev videobuf2_memops videobuf2_v4l2 raspberrypi_hwmon videodev videobuf2_common mc snd_bcm2835(C) raspberrypi_gpiomem nvmem_rmem uio_pdrv_genirq uio i2c_dev ledtrig_pattern fuse dm_mod ip_tables x_tables ipv6 rtc_ds1307 regmap_i2c vc4 v3d gpu_sched snd_soc_hdmi_codec drm_shmem_helper drm_display_helper cec drm_dma_helper drm_kms_helper i2c_brcmstb drm drm_panel_orientation_quirks i2c_bcm2835 snd_soc_core snd_compress snd_pcm_dmaengine snd_pcm snd_timer snd backlight
[ 220.964745] CPU: 3 UID: 0 PID: 87 Comm: kworker/u20:2 Tainted: G WC 6.12.20+rpt-rpi-v8 #1 Debian 1:6.12.20-1+rpt1~bpo12+1
[ 220.964763] Tainted: [W]=WARN, [C]=CRAP
[ 220.964770] Hardware name: Raspberry Pi Compute Module 4S Rev 1.0 (DT)
[ 220.964778] Workqueue: events_unbound commit_work [drm_kms_helper]
[ 220.964859] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 220.964871] pc : vc4_atomic_commit_tail+0x900/0x920 [vc4]
[ 220.964930] lr : vc4_atomic_commit_tail+0x1f4/0x920 [vc4]
[ 220.964985] sp : ffffffc08113bd00
[ 220.964991] x29: ffffffc08113bd00 x28: 0000000000000000 x27: 0000000000000000
[ 220.965012] x26: ffffff8041210080 x25: 0000000000000038 x24: ffffff8044fd53c0
[ 220.965033] x23: ffffff8041210080 x22: ffffff80410be680 x21: ffffff804558a000
[ 220.965053] x20: 0000000000000006 x19: 0000000001fb00f8 x18: 0000000000000000
[ 220.965074] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
[ 220.965094] x14: 0000000000000000 x13: 000000000ee6b280 x12: 0000000480000008
[ 220.965114] x11: ffffffc08002d000 x10: 0000000000001a40 x9 : ffffffe614a23c74
[ 220.965135] x8 : 0000000000000040 x7 : 000000000ee6b280 x6 : 0ee6b28000000004
[ 220.965155] x5 : 0000000000000001 x4 : 0000000000000000 x3 : 0000000000000000
[ 220.965174] x2 : ffffff804592a100 x1 : ffffff804592a100 x0 : 00000000ffffffea
[ 220.965194] Call trace:
[ 220.965201] vc4_atomic_commit_tail+0x900/0x920 [vc4]
[ 220.965257] commit_tail+0xac/0x1a0 [drm_kms_helper]
[ 220.965333] commit_work+0x1c/0x30 [drm_kms_helper]
[ 220.965407] process_one_work+0x158/0x3d0
[ 220.965423] worker_thread+0x2d8/0x3e8
[ 220.965437] kthread+0x11c/0x128
[ 220.965449] ret_from_fork+0x10/0x20
[ 220.965463] ---[ end trace 0000000000000000 ]---
{ More of the same}
Additional context
The problems seems to only occur on a CM4S. I don't see the issue on a CM3+ or CM4.
I don't notice any behavioral anomalies. Everything seems to work fine. The logs are just getting flooded repeatedly with the aforementioned kernel warning.
config.txt
hdmi_group=2
hdmi_mode=87
hdmi_cvt 800 480 60 6 0 0 0
dtparam=i2c_arm=on
dtoverlay=i2c-rtc,ds3231
enable_uart=1
core_freq=250
dtoverlay=uart1,txd1_pin=32,rxd1_pin=33
dtparam=audio=on
dtoverlay=audremap,pins_40_41
otg_mode=1
gpio=31=op,np,dh
gpio=34=op,np,dh
gpio=4-13=ip
gpio=16=ip
gpio=17-27=op,np,dl
gpio=37-39=op,np,dh
dtoverlay=vc4-kms-v3d,noaudio
auto_initramfs=1
disable_fw_kms_setup=1
disable_splash=1
avoid_warnings=1
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