Re: [PATCH 6.12 0000/1102] 6.12.111-rc1 review

["Barry K. Nathan" <barryn@pobox.com>]

(Added Kuniyuki Iwashima and Eric Dumazet because they were tagged
on the commit that I bisected this to.)

On 9/19/26 12:00 AM, Barry K. Nathan wrote:
> On 9/17/26 7:59 AM, Greg Kroah-Hartman wrote:
>> This is the start of the stable review cycle for the 6.12.111 release.
>> There are 1102 patches in this series, all will be posted as a response
>> to this one.  If anyone has any issues with these being applied, please
>> let me know.
>>
>> Responses should be made by Sat, 19 Sep 2026 15:13:49 +0000.
>> Anything received after that time might be too late.
>>
>> The whole patch series can be found in one patch at:
>>     https://www.kernel.org/pub/linux/kernel/v6.x/stable-review/patch-6.12.111-rc1.gz
>> or in the git tree and branch at:
>>     git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-6.12.y
>> and the diffstat can be found below.
>>
>> thanks,
>>
>> greg k-h
> 
> I tested 6.12.110 + up-to-date stable-queue as of this writing, commit
> 01b20bb84b994fdcda64fd07a66ba84c85d0168f, on my Lenovo ThinkPad T14 Gen 1.
> (If necessary, I can explain later how my workflow ends up giving this
> kernel the version number "6.12.111-pre158", but hopefully that detail
> won't be relevant.)
> 
> I'm seeing different kernel warnings than the other ones that have been
> posted in this thread so far. Here is one of them; I can reproduce this
> with the following steps:
> 
> 1. Boot
> 2. Log in
> 3. Wait 30 seconds or so
> 4. Close the laptop lid and wait for it to suspend
> 5. Open the laptop lid and unlock my desktop
> 6. Check dmesg and see if there's a warning there. If so, I'm done. If not,
>     repeat steps 4 and 5.
> 
> Sometimes the warning appears after only 1 suspend/wake cycle, but it
> always shows up no later than the second suspend/wake cycle.

Now that I've done more testing, it sometimes doesn't happen until a
third suspend/wake cycle. (It also happens within 15 seconds of boot
fairlyoften, though, so maybe I could have tried rebooting several
times instead of doing suspend/wake.)

> I'll verify that this still reproduces with a more minimal config, then
> I'll go ahead and bisect...
> 
> (On this ThinkPad I'm running Debian trixie and GNOME, in case it
> matters.)
> 
> [   98.363836] ------------[ cut here ]------------
> [   98.363843] RTNL: assertion failed at net/ipv6/mcast.c (1014)
> [   98.363896] WARNING: CPU: 6 PID: 961 at net/ipv6/mcast.c:1014 __ipv6_dev_mc_dec+0x17b/0x190 [ipv6]
> [   98.363977] Modules linked in: sd_mod scsi_mod scsi_common snd_seq_dummy snd_hrtimer snd_seq snd_seq_device rfcomm algif_hash algif_skcipher af_alg qrtr bnep snd_soc_skl_hda_dsp snd_soc_intel_sof_board_helpers snd_sof_probes snd_soc_intel_hda_dsp_common intel_uncore_frequency intel_uncore_frequency_common binfmt_misc intel_pmc_core_pltdrv intel_pmc_core intel_vsec pmt_telemetry pmt_class x86_pkg_temp_thermal nls_ascii nls_cp437 snd_hda_codec_realtek vfat fat snd_hda_codec_generic snd_hda_scodec_component snd_soc_dmic snd_sof_pci_intel_cnl snd_sof_intel_hda_generic soundwire_intel soundwire_cadence snd_sof_intel_hda_common snd_soc_hdac_hda intel_powerclamp snd_sof_intel_hda_mlink coretemp snd_sof_intel_hda snd_hda_codec_hdmi snd_sof_pci kvm_intel snd_sof_xtensa_dsp snd_sof snd_sof_utils snd_soc_acpi_intel_match kvm soundwire_generic_allocation snd_soc_acpi soundwire_bus iwlmvm snd_soc_avs irqbypass snd_soc_hda_codec snd_hda_ext_core crct10dif_pclmul mac80211 snd_soc_core 
> ghash_clmulni_intel mei_wdt mei_hdcp
> [   98.364043]  sha512_ssse3 intel_rapl_msr sha256_ssse3 mei_pxp sha1_ssse3 uvcvideo snd_compress snd_pcm_dmaengine aesni_intel libarc4 snd_hda_intel uvc crypto_simd videobuf2_vmalloc snd_intel_dspcfg cryptd btusb videobuf2_memops videobuf2_v4l2 btrtl snd_intel_sdw_acpi btintel rapl btbcm snd_hda_codec videodev intel_cstate iwlwifi btmtk processor_thermal_device_pci_legacy snd_hda_core videobuf2_common rmi_smbus processor_thermal_device intel_uncore snd_ctl_led pcspkr processor_thermal_wt_hint mc bluetooth rmi_core processor_thermal_rfim snd_hwdep processor_thermal_rapl cfg80211 think_lmi intel_wmi_thunderbolt snd_pcm intel_rapl_common firmware_attributes_class thinkpad_acpi ee1004 snd_timer processor_thermal_wt_req crc16 mei_me nvram wmi_bmof processor_thermal_power_floor platform_profile mei processor_thermal_mbox snd intel_soc_dts_iosf intel_pch_thermal int3403_thermal joydev soundcore int340x_thermal_zone ac int3400_thermal intel_hid acpi_thermal_rel sparse_keymap button 
> acpi_pad evdev msr i2c_dev parport_pc ppdev lp
> [   98.364124]  parport dm_mod nvme_fabrics efi_pstore configfs nfnetlink ip_tables x_tables ipv6 autofs4 xfs btrfs blake2b_generic raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 linear md_mod hid_multitouch hid_generic usbhid hid i915 drm_buddy i2c_algo_bit iTCO_wdt drm_display_helper intel_pmc_bxt iTCO_vendor_support rtsx_pci_sdmmc watchdog ucsi_acpi mmc_core psmouse i2c_i801 cec typec_ucsi xhci_pci nvme video crc32_pclmul rc_core thunderbolt xhci_hcd e1000e crc32c_intel serio_raw roles nvme_core ttm i2c_smbus rtsx_pci typec battery wmi efivarfs
> [   98.364208] CPU: 6 UID: 105 PID: 961 Comm: avahi-daemon Not tainted 6.12.111-pre158 #3
> [   98.364214] Hardware name: LENOVO 20S1S6D700/20S1S6D700, BIOS N2XET46W (1.36 ) 06/02/2026
> [   98.364217] RIP: 0010:__ipv6_dev_mc_dec+0x17b/0x190 [ipv6]
> [   98.364291] Code: 88 f5 02 00 00 0f 85 c4 fe ff ff ba f6 03 00 00 48 c7 c6 30 8f 3b c1 48 c7 c7 58 7b 3b c1 c6 05 68 f5 02 00 01 e8 95 fd f5 e4 <0f> 0b e9 9e fe ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90
> [   98.364296] RSP: 0018:ffffd3da8074b8c0 EFLAGS: 00010246
> [   98.364301] RAX: 0000000000000000 RBX: ffff8e5e03638800 RCX: 0000000000000000
> [   98.364304] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> [   98.364307] RBP: ffff8e5e09238540 R08: 0000000000000000 R09: 0000000000000000
> [   98.364311] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8e5e2088ae80
> [   98.364314] R13: ffff8e5e03638800 R14: ffff8e5e03638a70 R15: 0000000000000000
> [   98.364318] FS:  00007f6719a89840(0000) GS:ffff8e652c500000(0000) knlGS:0000000000000000
> [   98.364322] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   98.364326] CR2: 00007f38ae7fcd58 CR3: 000000010b64c004 CR4: 00000000003726f0
> [   98.364329] Call Trace:
> [   98.364334]  <TASK>
> [   98.364339]  ipv6_sock_mc_drop+0x122/0x1e0 [ipv6]
> [   98.364409]  do_ipv6_setsockopt+0xb9b/0x1a30 [ipv6]
> [   98.364479]  ? __wake_up_sync_key+0x3b/0x60
> [   98.364486]  ? sock_def_readable+0x42/0xc0
> [   98.364490]  ? unix_dgram_sendmsg+0x5d5/0x9c0
> [   98.364499]  ipv6_setsockopt+0x5e/0xa0 [ipv6]
> [   98.364570]  do_sock_setsockopt+0xb9/0x190
> [   98.364578]  __sys_setsockopt+0x94/0xe0
> [   98.364584]  __x64_sys_setsockopt+0x1f/0x40
> [   98.364589]  do_syscall_64+0x82/0x1b0
> [   98.364595]  ? syscall_exit_to_user_mode+0x32/0x190
> [   98.364601]  ? do_syscall_64+0x8e/0x1b0
> [   98.364607]  ? file_update_time+0x1b/0x90
> [   98.364615]  ? pipe_write+0x424/0x670
> [   98.364623]  ? vfs_write+0x3b6/0x450
> [   98.364630]  ? arch_exit_to_user_mode_prepare.isra.0+0x1e/0x100
> [   98.364636]  ? syscall_exit_to_user_mode+0x32/0x190
> [   98.364643]  ? do_syscall_64+0x8e/0x1b0
> [   98.364649]  ? do_syscall_64+0x8e/0x1b0
> [   98.364655]  ? arch_exit_to_user_mode_prepare.isra.0+0x1e/0x100
> [   98.364661]  ? syscall_exit_to_user_mode+0x32/0x190
> [   98.364667]  ? do_syscall_64+0x8e/0x1b0
> [   98.364675]  ? __sys_sendmsg+0x87/0xf0
> [   98.364681]  ? arch_exit_to_user_mode_prepare.isra.0+0x1e/0x100
> [   98.364686]  ? syscall_exit_to_user_mode+0x32/0x190
> [   98.364692]  ? do_syscall_64+0x8e/0x1b0
> [   98.364698]  ? do_syscall_64+0x8e/0x1b0
> [   98.364703]  ? arch_exit_to_user_mode_prepare.isra.0+0x1e/0x100
> [   98.364708]  ? syscall_exit_to_user_mode+0x32/0x190
> [   98.364714]  ? do_syscall_64+0x8e/0x1b0
> [   98.364719]  ? clear_bhb_loop+0x70/0xc0
> [   98.364726]  ? clear_bhb_loop+0x70/0xc0
> [   98.364732]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> [   98.364738] RIP: 0033:0x7f6719c8fffa
> [   98.364763] Code: 48 83 ec 10 48 63 c9 48 63 ff 45 89 c9 6a 2c e8 dc d3 f7 ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 49 89 ca b8 36 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 06 c3 0f 1f 44 00 00 48 8b 15 e1 2d 0d 00 f7
> [   98.364767] RSP: 002b:00007ffc2ea2ab08 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
> [   98.364773] RAX: ffffffffffffffda RBX: 000000000000000d RCX: 00007f6719c8fffa
> [   98.364777] RDX: 0000000000000015 RSI: 0000000000000029 RDI: 000000000000000d
> [   98.364781] RBP: 0000000000000002 R08: 0000000000000014 R09: 00000000fffffff9
> [   98.364784] R10: 00007ffc2ea2ab10 R11: 0000000000000246 R12: 0000000000000000
> [   98.364787] R13: 000055cc8f2201a0 R14: 0000000000000000 R15: 000055cc8f21dec0
> [   98.364795]  </TASK>
> [   98.364797] ---[ end trace 0000000000000000 ]---
> 

I bisected it to this patch:
ipv6-mcast-don-t-hold-rtnl-for-ipv6_drop_membership-.patch.

With that patch, the warning happens, without it, it doesn't.


If I take 6.12.110, apply the current stable-queue (as of commit
01b20bb84b994fdcda64fd07a66ba84c85d0168f), then revert the
following patches:

ipv6-mcast-don-t-hold-rtnl-for-ipv6_drop_membership-.patch
ipv6-mcast-don-t-hold-rtnl-for-mcast_-socket-options.patch
ipv6-mcast-use-copy-on-write-rcu-updates-in-ip6_mc_s.patch

then the resulting kernel no longer shows these warnings at all.

-- 
-Barry K. Nathan  <barryn@pobox.com>