Describe the bug
Following up on the previous phase1_cb issue (fixed by 6.18 — thanks): plain HEVC playback now works, but a pipeline that performs an accurate segment seek while PAUSED before going to PLAYING hangs the decoder: the process enters uninterruptible D state (survives SIGKILL), and the machine needs a reboot to recover DRM/the decoder. Sometimes (2 occurrences out of 4) the kernel logs:
WARNING: CPU: 0 PID: 1453 at drivers/media/mc/mc-request.c:470 media_request_object_unbind+0x178/0x1f0 [mc]
…followed by GStreamer reporting "Not enough memory to decode H265 stream" (CMA has 465 MB free). The hang itself is 100 % reproducible (4/4 attempts).
Steps to reproduce the behaviour
Attached: repro_mc_request.py (30 lines: PAUSED → accurate FLUSH|SEGMENT seek to 2 s → PLAYING) and the 44 KB SMPTE-bars test file from the previous issue.
sudo python3 repro_mc_request.py test_hevc_1080p25.mp4
Expected: 60 s of playback then "clean exit". Actual: no output, process wedged in D state, reboot required. Full kernel traces from two occurrences attached (traces_completes.txt).
repro_mc_request.py
Device (s)
Raspberry Pi 4 Mod. B
System
Raspberry Pi 4B rev 1.5 — kernel 6.18.39+rpt-rpi-v8 — GStreamer 1.26.2 (Debian trixie)
Raspberry Pi 5 on the same kernel is NOT affected (same script runs clean)
Plain playback (gst-launch-1.0 filesrc ! qtdemux ! h265parse ! v4l2slh265dec ! kmssink) is also clean — the seek is the trigger
Logs
########## BOOT -1 ###########1 PREEMPT Debian 1:6.18.39-1+rpt1#1 PREEMPT Debian 1:6.18.39-1+rpt1#1 PREEMPT Debian 1:6.18.39-1+rpt1
Additional context
test_hevc_1080p25.mp4
Describe the bug
Following up on the previous phase1_cb issue (fixed by 6.18 — thanks): plain HEVC playback now works, but a pipeline that performs an accurate segment seek while PAUSED before going to PLAYING hangs the decoder: the process enters uninterruptible D state (survives SIGKILL), and the machine needs a reboot to recover DRM/the decoder. Sometimes (2 occurrences out of 4) the kernel logs:
WARNING: CPU: 0 PID: 1453 at drivers/media/mc/mc-request.c:470 media_request_object_unbind+0x178/0x1f0 [mc]…followed by GStreamer reporting "Not enough memory to decode H265 stream" (CMA has 465 MB free). The hang itself is 100 % reproducible (4/4 attempts).
Steps to reproduce the behaviour
Attached: repro_mc_request.py (30 lines: PAUSED → accurate FLUSH|SEGMENT seek to 2 s → PLAYING) and the 44 KB SMPTE-bars test file from the previous issue.
sudo python3 repro_mc_request.py test_hevc_1080p25.mp4Expected: 60 s of playback then "clean exit". Actual: no output, process wedged in D state, reboot required. Full kernel traces from two occurrences attached (traces_completes.txt).
repro_mc_request.py
Device (s)
Raspberry Pi 4 Mod. B
System
Logs
########## BOOT -1 ##########
Aug 03 16:32:58 xxxxx kernel: ------------[ cut here ]------------
Aug 03 16:32:58 xxxxx kernel: WARNING: CPU: 0 PID: 608 at drivers/gpu/drm/vc4/vc4_hvs.c:1064 __vc4_hvs_stop_channel+0x158/0x180 [vc4]
Aug 03 16:32:58 xxxxx kernel: Modules linked in: rfcomm cmac algif_hash aes_arm64 algif_skcipher af_alg bnep brcmfmac_cyw binfmt_misc brcmfmac brcmutil hci_uart btbcm cfg80211 bluetooth ecdh_generic ecc v3d rfkill vc4 raspberrypi_hwmon gpu_sched bcm2835_codec(C) bcm2835_v4l2(C) bcm2835_isp(C) drm_shmem_helper snd_soc_hdmi_codec i2c_brcmstb bcm2835_mmal_vchiq(C) drm_exec drm_display_helper cec snd_bcm2835(C) rpi_hevc_dec drm_dma_helper drm_client_lib raspberrypi_gpiomem vc_sm_cma(C) drm_kms_helper videobuf2_vmalloc v4l2_mem2mem snd_soc_core videobuf2_dma_contig videobuf2_memops videobuf2_v4l2 snd_compress snd_pcm_dmaengine videodev snd_pcm videobuf2_common snd_timer mc snd nvmem_rmem sch_fq_codel i2c_dev zram lz4_compress drm fuse drm_panel_orientation_quirks backlight nfnetlink ipv6 libsha1
Aug 03 16:32:58 xxxxx kernel: CPU: 0 UID: 0 PID: 608 Comm: kworker/0:3 Tainted: G C 6.18.39+rpt-rpi-v8 #1 PREEMPT Debian 1:6.18.39-1+rpt1
Aug 03 16:32:58 xxxxx kernel: Tainted: [C]=CRAP
Aug 03 16:32:58 xxxxx kernel: Hardware name: Raspberry Pi 4 Model B Rev 1.5 (DT)
Aug 03 16:32:58 xxxxx kernel: Workqueue: events console_callback
Aug 03 16:32:58 xxxxx kernel: pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
Aug 03 16:32:58 xxxxx kernel: pc : __vc4_hvs_stop_channel+0x158/0x180 [vc4]
Aug 03 16:32:58 xxxxx kernel: lr : __vc4_hvs_stop_channel+0x50/0x180 [vc4]
Aug 03 16:32:58 xxxxx kernel: sp : ffffffc082c7b7f0
Aug 03 16:32:58 xxxxx kernel: x29: ffffffc082c7b800 x28: ffffff8043018920 x27: 0000000000000038
Aug 03 16:32:58 xxxxx kernel: x26: ffffffedd07a8b80 x25: 00000003edb5ee72 x24: ffffff8047ed3000
Aug 03 16:32:58 xxxxx kernel: x23: ffffff8042dec180 x22: 0000000000000001 x21: ffffff8045730500
Aug 03 16:32:58 xxxxx kernel: x20: ffffff80439f8080 x19: 0000000000000001 x18: 0000000000000000
Aug 03 16:32:58 xxxxx kernel: x17: 0000000000000000 x16: ffffffee0096a558 x15: 000015335a37fe90
Aug 03 16:32:58 xxxxx kernel: x14: 00000007f3904070 x13: 0000000000000115 x12: 0000000000000007
Aug 03 16:32:58 xxxxx kernel: x11: 00000000000000c0 x10: 0000000000001ac0 x9 : ffffffedd041c2cc
Aug 03 16:32:58 xxxxx kernel: x8 : ffffff804754bca0 x7 : 0000000000000001 x6 : 0000000000000000
Aug 03 16:32:58 xxxxx kernel: x5 : 00000000000001ef x4 : 0000000000000000 x3 : 0000000040000000
Aug 03 16:32:58 xxxxx kernel: x2 : 0000000000000000 x1 : 0000000010000000 x0 : 0000000000000000
Aug 03 16:32:58 xxxxx kernel: Call trace:
Aug 03 16:32:58 xxxxx kernel: __vc4_hvs_stop_channel+0x158/0x180 [vc4] (P)
Aug 03 16:32:58 xxxxx kernel: vc4_hvs_stop_channel+0x38/0x50 [vc4]
Aug 03 16:32:58 xxxxx kernel: vc4_crtc_disable+0x13c/0x1e8 [vc4]
Aug 03 16:32:58 xxxxx kernel: vc4_crtc_atomic_disable+0xa0/0xe8 [vc4]
Aug 03 16:32:58 xxxxx kernel: drm_atomic_helper_commit_crtc_disable+0x114/0x1f8 [drm_kms_helper]
Aug 03 16:32:58 xxxxx kernel: drm_atomic_helper_commit_modeset_disables+0x3c/0x80 [drm_kms_helper]
Aug 03 16:32:58 xxxxx kernel: vc4_atomic_commit_tail+0x158/0x990 [vc4]
Aug 03 16:32:58 xxxxx kernel: commit_tail+0xa8/0x1b0 [drm_kms_helper]
Aug 03 16:32:58 xxxxx kernel: drm_atomic_helper_commit+0x184/0x1c0 [drm_kms_helper]
Aug 03 16:32:58 xxxxx kernel: drm_atomic_commit+0x94/0xe0 [drm]
Aug 03 16:32:58 xxxxx kernel: drm_client_modeset_commit_atomic+0x220/0x298 [drm]
Aug 03 16:32:58 xxxxx kernel: drm_client_modeset_dpms+0x90/0x250 [drm]
Aug 03 16:32:58 xxxxx kernel: drm_fb_helper_blank+0x8c/0x118 [drm_kms_helper]
Aug 03 16:32:58 xxxxx kernel: fb_blank+0x4c/0xc0
Aug 03 16:32:58 xxxxx kernel: fbcon_blank+0x148/0x268
Aug 03 16:32:58 xxxxx kernel: do_blank_screen+0xc8/0x208
Aug 03 16:32:58 xxxxx kernel: console_callback+0xdc/0x170
Aug 03 16:32:58 xxxxx kernel: process_one_work+0x158/0x3b8
Aug 03 16:32:58 xxxxx kernel: worker_thread+0x19c/0x328
Aug 03 16:32:58 xxxxx kernel: kthread+0x14c/0x210
Aug 03 16:32:58 xxxxx kernel: ret_from_fork+0x10/0x20
Aug 03 16:32:58 xxxxx kernel: ---[ end trace 0000000000000000 ]---
Aug 03 17:25:22 xxxxx kernel: ------------[ cut here ]------------
Aug 03 17:25:22 xxxxx kernel: WARNING: CPU: 2 PID: 2286 at drivers/media/mc/mc-request.c:470 media_request_object_unbind+0x178/0x1f0 [mc]
Aug 03 17:25:22 xxxxx kernel: Modules linked in: snd_seq_dummy snd_hrtimer snd_seq snd_seq_device tun rfcomm cmac algif_hash aes_arm64 algif_skcipher af_alg bnep brcmfmac_cyw binfmt_misc brcmfmac brcmutil hci_uart btbcm cfg80211 bluetooth ecdh_generic ecc v3d rfkill vc4 raspberrypi_hwmon gpu_sched bcm2835_codec(C) bcm2835_v4l2(C) bcm2835_isp(C) drm_shmem_helper snd_soc_hdmi_codec i2c_brcmstb bcm2835_mmal_vchiq(C) drm_exec drm_display_helper cec snd_bcm2835(C) rpi_hevc_dec drm_dma_helper drm_client_lib raspberrypi_gpiomem vc_sm_cma(C) drm_kms_helper videobuf2_vmalloc v4l2_mem2mem snd_soc_core videobuf2_dma_contig videobuf2_memops videobuf2_v4l2 snd_compress snd_pcm_dmaengine videodev snd_pcm videobuf2_common snd_timer mc snd nvmem_rmem sch_fq_codel i2c_dev zram lz4_compress drm fuse drm_panel_orientation_quirks backlight nfnetlink ipv6 libsha1
Aug 03 17:25:22 xxxxx kernel: CPU: 2 UID: 0 PID: 2286 Comm: queue0:src Tainted: G WC 6.18.39+rpt-rpi-v8 #1 PREEMPT Debian 1:6.18.39-1+rpt1
Aug 03 17:25:22 xxxxx kernel: Tainted: [W]=WARN, [C]=CRAP
Aug 03 17:25:22 xxxxx kernel: Hardware name: Raspberry Pi 4 Model B Rev 1.5 (DT)
Aug 03 17:25:22 xxxxx kernel: pstate: 800000c5 (Nzcv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
Aug 03 17:25:22 xxxxx kernel: pc : media_request_object_unbind+0x178/0x1f0 [mc]
Aug 03 17:25:22 xxxxx kernel: lr : media_request_object_unbind+0x34/0x1f0 [mc]
Aug 03 17:25:22 xxxxx kernel: sp : ffffffc08b2e3b00
Aug 03 17:25:22 xxxxx kernel: x29: ffffffc08b2e3b00 x28: ffffff8041404b48 x27: 0000000000000000
Aug 03 17:25:22 xxxxx kernel: x26: 0000000000000009 x25: 0000000000000000 x24: ffffff8041404900
Aug 03 17:25:22 xxxxx kernel: x23: ffffff80478c6f00 x22: ffffff8042e53b68 x21: 0000000000000000
Aug 03 17:25:22 xxxxx kernel: x20: ffffff8042e53b00 x19: ffffff80424c8c98 x18: 0000000000000150
Aug 03 17:25:22 xxxxx kernel: x17: 0000000000000000 x16: ffffffee0169f148 x15: 0000000000000000
Aug 03 17:25:22 xxxxx kernel: x14: 0000000000000177 x13: 000000001dcd6500 x12: 0000000480000008
Aug 03 17:25:22 xxxxx kernel: x11: ffffffc08002d000 x10: 0000000000001ac0 x9 : ffffffedd04f8e4c
Aug 03 17:25:22 xxxxx kernel: x8 : ffffffc08b2e3b88 x7 : 0000000000000000 x6 : 0000000000000000
Aug 03 17:25:22 xxxxx kernel: x5 : ffffff80478c6f00 x4 : dead000000000122 x3 : ffffff8042e53b38
Aug 03 17:25:22 xxxxx kernel: x2 : 0000000000000002 x1 : dead000000000100 x0 : 0000000000000000
Aug 03 17:25:22 xxxxx kernel: Call trace:
Aug 03 17:25:22 xxxxx kernel: media_request_object_unbind+0x178/0x1f0 [mc] (P)
Aug 03 17:25:22 xxxxx kernel: v4l2_ctrl_handler_free_request+0x74/0xb0 [videodev]
Aug 03 17:25:22 xxxxx kernel: v4l2_ctrl_handler_free+0x38/0x1a0 [videodev]
Aug 03 17:25:22 xxxxx kernel: hevc_d_release+0x30/0x68 [rpi_hevc_dec]
Aug 03 17:25:22 xxxxx kernel: v4l2_release+0x6c/0xf8 [videodev]
Aug 03 17:25:22 xxxxx kernel: __fput+0xd4/0x2f8
Aug 03 17:25:22 xxxxx kernel: ____fput+0x1c/0x30
Aug 03 17:25:22 xxxxx kernel: task_work_run+0x88/0x100
Aug 03 17:25:22 xxxxx kernel: do_exit+0x290/0x9d8
Aug 03 17:25:22 xxxxx kernel: do_group_exit+0x3c/0xa0
Aug 03 17:25:22 xxxxx kernel: get_signal+0x938/0xa10
Aug 03 17:25:22 xxxxx kernel: arch_do_signal_or_restart+0xa0/0x3c0
Aug 03 17:25:22 xxxxx kernel: exit_to_user_mode_loop+0xf8/0x178
Aug 03 17:25:22 xxxxx kernel: el0_svc+0x118/0x120
Aug 03 17:25:22 xxxxx kernel: el0t_64_sync_handler+0xa0/0xe8
Aug 03 17:25:22 xxxxx kernel: el0t_64_sync+0x198/0x1a0
Aug 03 17:25:22 xxxxx kernel: ---[ end trace 0000000000000000 ]---
Aug 03 17:25:22 xxxxx kernel: ------------[ cut here ]------------
Aug 03 17:25:22 xxxxx kernel: WARNING: CPU: 2 PID: 2286 at drivers/media/mc/mc-request.c:470 media_request_object_unbind+0x178/0x1f0 [mc]
Aug 03 17:25:22 xxxxx kernel: Modules linked in: snd_seq_dummy snd_hrtimer snd_seq snd_seq_device tun rfcomm cmac algif_hash aes_arm64 algif_skcipher af_alg bnep brcmfmac_cyw binfmt_misc brcmfmac brcmutil hci_uart btbcm cfg80211 bluetooth ecdh_generic ecc v3d rfkill vc4 raspberrypi_hwmon gpu_sched bcm2835_codec(C) bcm2835_v4l2(C) bcm2835_isp(C) drm_shmem_helper snd_soc_hdmi_codec i2c_brcmstb bcm2835_mmal_vchiq(C) drm_exec drm_display_helper cec snd_bcm2835(C) rpi_hevc_dec drm_dma_helper drm_client_lib raspberrypi_gpiomem vc_sm_cma(C) drm_kms_helper videobuf2_vmalloc v4l2_mem2mem snd_soc_core videobuf2_dma_contig videobuf2_memops videobuf2_v4l2 snd_compress snd_pcm_dmaengine videodev snd_pcm videobuf2_common snd_timer mc snd nvmem_rmem sch_fq_codel i2c_dev zram lz4_compress drm fuse drm_panel_orientation_quirks backlight nfnetlink ipv6 libsha1
Aug 03 17:25:22 xxxxx kernel: CPU: 2 UID: 0 PID: 2286 Comm: queue0:src Tainted: G WC 6.18.39+rpt-rpi-v8 #1 PREEMPT Debian 1:6.18.39-1+rpt1
Aug 03 17:25:22 xxxxx kernel: Tainted: [W]=WARN, [C]=CRAP
Aug 03 17:25:22 xxxxx kernel: Hardware name: Raspberry Pi 4 Model B Rev 1.5 (DT)
Aug 03 17:25:22 xxxxx kernel: pstate: 800000c5 (Nzcv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
Aug 03 17:25:22 xxxxx kernel: pc : media_request_object_unbind+0x178/0x1f0 [mc]
Aug 03 17:25:22 xxxxx kernel: lr : media_request_object_unbind+0x34/0x1f0 [mc]
Aug 03 17:25:22 xxxxx kernel: sp : ffffffc08b2e3b00
Aug 03 17:25:22 xxxxx kernel: x29: ffffffc08b2e3b00 x28: ffffff8041404b48 x27: 0000000000000000
Aug 03 17:25:22 xxxxx kernel: x26: 0000000000000009 x25: 0000000000000000 x24: ffffff8041404900
Aug 03 17:25:22 xxxxx kernel: x23: ffffff80478c6f00 x22: ffffff8041f1f5e8 x21: 0000000000000000
Aug 03 17:25:22 xxxxx kernel: x20: ffffff8041f1f580 x19: ffffff80424c8498 x18: 0000000000000150
Aug 03 17:25:22 xxxxx kernel: x17: 0000000000000000 x16: ffffffee0169f148 x15: 0000000000000000
Aug 03 17:25:22 xxxxx kernel: x14: 0000000000000177 x13: 000000001dcd6500 x12: 0000000480000008
Aug 03 17:25:22 xxxxx kernel: x11: ffffffc08002d000 x10: 0000000000001ac0 x9 : ffffffedd04f8e4c
Additional context
test_hevc_1080p25.mp4