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

[Peter Schneider]

Am 17.09.2026 um 22:19 schrieb Peter Schneider:
> Am 17.09.2026 um 21:35 schrieb Brett A C Sheffield:
> > # first 'bad' commit: [22ae428b0045981bd19f8c75f700a67198062f32] mm/hugetlb: initialize gigantic bootmem hugepage 
> > struct pages earlier
>
> Yes, that's what I found, too.
>
> When I revert 22ae428b0045981bd19f8c75f700a67198062f32 from rc1, the boot crash goes away and my machine boots 
> successfully.
>
> However, then I have another weirdo in the dmesg output:
>
> [   65.573304] ------------[ cut here ]------------
> [   65.573307] WARNING: CPU: 14 PID: 0 at kernel/sched/fair.c:5303 place_entity+0x13b/0x140
> [   65.573316] Modules linked in: uas usbhid usb_storage hid isci psmouse igb crc32_pclmul libsas aacraid serio_raw 
> i2c_i801 ioatdma ahci ehci_pci i2c_mux ehci_hcd i2c_algo_bit libahci i2c_smbus scsi_transport_sas lpc_ich dca wmi
> [   65.573336] CPU: 14 UID: 0 PID: 0 Comm: swapper/14 Not tainted 6.12.111-rc1+ #1
> [   65.573339] Hardware name: ASUSTeK COMPUTER INC. Z9PE-D16 Series/Z9PE-D16 Series, BIOS 5601 06/11/2015
> [   65.573342] RIP: 0010:place_entity+0x13b/0x140
> [   65.573345] Code: 41 5d 41 5e 5d 31 c0 31 d2 31 c9 31 f6 31 ff c3 cc cc cc cc be 02 00 00 00 48 c1 e9 0a 48 39 f1 48 
> 0f 42 ce 48 8d 34 11 eb a9 <0f> 0b eb b6 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f
> [   65.573347] RSP: 0018:ffffd09188287cd8 EFLAGS: 00010046
> [   65.573350] RAX: 0000000000000000 RBX: ffff8bc1cb32ce00 RCX: 00000000000003cb
> [   65.573352] RDX: 0000000000000000 RSI: 00000000000003cb RDI: 00000000002d0e7f
> [   65.573353] RBP: ffffd09188287cf8 R08: 0000000000000000 R09: 0000000000000000
> [   65.573355] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000037e492a9
> [   65.573356] R13: ffff8be13f337280 R14: 0000000000000000 R15: 0000000000000000
> [   65.573357] FS:  0000000000000000(0000) GS:ffff8be13f300000(0000) knlGS:0000000000000000
> [   65.573359] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   65.573361] CR2: 0000650f5b7d2118 CR3: 000000208ccca006 CR4: 00000000001706f0
> [   65.573363] Call Trace:
> [   65.573366]  <TASK>
> [   65.573368]  reweight_entity+0x1d2/0x200
> [   65.573372]  update_cfs_group+0xb4/0xf0
> [   65.573374]  enqueue_task_fair+0x285/0x8f0
> [   65.573377]  enqueue_task+0x3b/0x220
> [   65.573383]  ttwu_do_activate+0x75/0x270
> [   65.573386]  sched_ttwu_pending+0xfe/0x1e0
> [   65.573389]  __flush_smp_call_function_queue+0x155/0x440
> [   65.573394]  flush_smp_call_function_queue+0x37/0x80
> [   65.573397]  do_idle+0x15d/0x2c0
> [   65.573401]  ? complete+0x6d/0x80
> [   65.573406]  cpu_startup_entry+0x29/0x30
> [   65.573409]  start_secondary+0x119/0x140
> [   65.573414]  common_startup_64+0x13e/0x141
> [   65.573420]  </TASK>
> [   65.573421] ---[ end trace 0000000000000000 ]---
So I have bisected this warning, and the first bad commit is

[af5775004c9c02f37be06d2035a056b6abb1cb6c] sched/fair: Fix EEVDF entity placement bug causing scheduling lag

Trying to revert this from 6.12.111-rc1 however resulted in some conflicts I was unable to resolve. There are other 
dependencies like:

Stable-dep-of: 51b0e68cfa0a ("sched/eevdf: Fix rb augmented with multi fields"), which is 
[09cd469c733035b01b445a6f916e8ea425330c45] in linux-next-rc)
and also [3bc70680c7ab333ed00a5e1fe33ed669c44d5544] ("sched/fair: Fix lag clamp").

This is my bisect log:


root@linus:/usr/src/linux-stable-rc# cat my_bisect.log
git bisect start
# Status: warte auf guten und schlechten Commit
# bad: [ae53f4b7c7f60eca321af54b4ada3f24082c242e] Revert "mm/hugetlb: initialize gigantic bootmem hugepage struct pages 
earlier"
git bisect bad ae53f4b7c7f60eca321af54b4ada3f24082c242e
# Status: warte auf gute(n) Commit(s), schlechter Commit bekannt
# good: [fa5b06866b643cce7072a4e7c6be7ee3f0f1b95c] Linux 6.12.110
git bisect good fa5b06866b643cce7072a4e7c6be7ee3f0f1b95c
# good: [0b70c4d3654f89b7fdfcae684ea7371fbc7de72c] Bluetooth: hci_core: Fix race condition during device registration
git bisect good 0b70c4d3654f89b7fdfcae684ea7371fbc7de72c
# bad: [818d7fa0a53b82f2e8db56aac615d08d3da72548] ASoC: sprd: validate compress buffer sizes against fixed allocations
git bisect bad 818d7fa0a53b82f2e8db56aac615d08d3da72548
# good: [56c7ca9d7037acb880cad9eae68c479cc4d6f200] net/mlx5: E-Switch: fix use-after-free in mlx5_eswitch_termtbl_put
git bisect good 56c7ca9d7037acb880cad9eae68c479cc4d6f200
# good: [03d4a3b6610bc9f86d8ec4d9a75a2d5376b47bb7] net: ks8851: Fix receiver error in 100BASE-TX mode following software 
power-down
git bisect good 03d4a3b6610bc9f86d8ec4d9a75a2d5376b47bb7
# bad: [1d8ee4f560be8b347173dc7c07fd41e4baa318d7] net: stmmac: add stmmac_tso_header_size()
git bisect bad 1d8ee4f560be8b347173dc7c07fd41e4baa318d7
# bad: [af5775004c9c02f37be06d2035a056b6abb1cb6c] sched/fair: Fix EEVDF entity placement bug causing scheduling lag
git bisect bad af5775004c9c02f37be06d2035a056b6abb1cb6c
# good: [7b6988750feec0bd3da256e9fe80244fa358ab74] net: stmmac: initialize ptp_lock at probe time
git bisect good 7b6988750feec0bd3da256e9fe80244fa358ab74
# good: [52080cefeb2f454cdb14fb7a052d35566609c1ad] perf/core: Check sample_type in perf_sample_save_callchain
git bisect good 52080cefeb2f454cdb14fb7a052d35566609c1ad
# good: [edeca3f32161462596e6e03e69a3443dd80c5603] perf/x86/intel/ds: Remove redundant assignments to sample.period
git bisect good edeca3f32161462596e6e03e69a3443dd80c5603
# good: [fc602eb1451422bf0e4798ac68f8c15904e0b7aa] perf/x86/intel: Correct pt_regs->flags update for PEBS path
git bisect good fc602eb1451422bf0e4798ac68f8c15904e0b7aa
# first bad commit: [af5775004c9c02f37be06d2035a056b6abb1cb6c] sched/fair: Fix EEVDF entity placement bug causing 
scheduling lag


Beste Grüße,
Peter Schneider

--
Climb the mountain not to plant your flag, but to embrace the challenge,
enjoy the air and behold the view. Climb it so you can see the world,
not so the world can see you.                    -- David McCullough Jr.

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