[tip:tmp.tmp] [sched/fair] eb2db043ab: BUG:kernel_NULL_pointer_dereference,address

[tip:tmp.tmp] [sched/fair] eb2db043ab: BUG:kernel_NULL_pointer_dereference,address

[kernel test robot]

Hello,

kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on:

commit: eb2db043ab3a28ae76800f2a57e144420800d56d ("sched/fair: Skip sched_balance_running cmpxchg when balance is not due")
https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git tmp.tmp

in testcase: fio-basic
version: fio-x86_64-7c8dbca4-1_20251123
with following parameters:

	runtime: 300s
	disk: 1SSD
	fs: btrfs
	nr_task: 100%
	test_size: 128G
	rw: randwrite
	bs: 4M
	ioengine: falloc
	cpufreq_governor: performance



config: x86_64-rhel-9.4
compiler: gcc-14
test machine: 192 threads 4 sockets Intel(R) Xeon(R) Platinum 9242 CPU @ 2.30GHz (Cascade Lake) with 176G memory

(please refer to attached dmesg/kmsg for entire log/backtrace)



If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202511271605.bd46ddc3-lkp@intel.com


[    5.764008][    C0] BUG: kernel NULL pointer dereference, address: 0000000000000000
[    5.764501][    T1] futex hash table entries: 16384 (1048576 bytes on 4 NUMA nodes, total 4096 KiB, linear).
[    5.764999][    C0] #PF: supervisor read access in kernel mode
[    5.764999][    C0] #PF: error_code(0x0000) - not-present page
[    5.764999][    T1] pinctrl core: initialized pinctrl subsystem
[    5.764999][    C0] PGD 0 P4D 0
[    5.764999][    C0] Oops: Oops: 0000 [#1] SMP NOPTI
[    5.764999][    C0] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G S                  6.18.0-rc6-00035-geb2db043ab3a #1 VOLUNTARY
[    5.764999][    C0] Tainted: [S]=CPU_OUT_OF_SPEC
[    5.764999][    C0] Hardware name: Intel Corporation ............/S9200WKBRD2, BIOS SE5C620.86B.0D.01.0552.060220191912 06/02/2019
[    5.764999][    C0] RIP: 0010:sched_balance_rq (arch/x86/include/asm/atomic.h:107 (discriminator 4) include/linux/atomic/atomic-arch-fallback.h:2170 (discriminator 4) include/linux/atomic/atomic-instrumented.h:1302 (discriminator 4) kernel/sched/fair.c:11733 (discriminator 4))
[    5.764999][    C0] Code: b8 00 00 00 65 48 2b 15 c2 47 a7 02 0f 85 30 03 00 00 48 81 c4 c0 00 00 00 89 f0 5b 5d 41 5c 41 5d 41 5e 41 5f e9 bc fb f5 00 <8b> 04 25 00 00 00 00 ba 01 00 00 00 f0 0f b1 15 58 d6 af 02 0f 94
All code
========
   0:	b8 00 00 00 65       	mov    $0x65000000,%eax
   5:	48 2b 15 c2 47 a7 02 	sub    0x2a747c2(%rip),%rdx        # 0x2a747ce
   c:	0f 85 30 03 00 00    	jne    0x342
  12:	48 81 c4 c0 00 00 00 	add    $0xc0,%rsp
  19:	89 f0                	mov    %esi,%eax
  1b:	5b                   	pop    %rbx
  1c:	5d                   	pop    %rbp
  1d:	41 5c                	pop    %r12
  1f:	41 5d                	pop    %r13
  21:	41 5e                	pop    %r14
  23:	41 5f                	pop    %r15
  25:	e9 bc fb f5 00       	jmp    0xf5fbe6
  2a:*	8b 04 25 00 00 00 00 	mov    0x0,%eax		<-- trapping instruction
  31:	ba 01 00 00 00       	mov    $0x1,%edx
  36:	f0 0f b1 15 58 d6 af 	lock cmpxchg %edx,0x2afd658(%rip)        # 0x2afd696
  3d:	02 
  3e:	0f                   	.byte 0xf
  3f:	94                   	xchg   %eax,%esp

Code starting with the faulting instruction
===========================================
   0:	8b 04 25 00 00 00 00 	mov    0x0,%eax
   7:	ba 01 00 00 00       	mov    $0x1,%edx
   c:	f0 0f b1 15 58 d6 af 	lock cmpxchg %edx,0x2afd658(%rip)        # 0x2afd66c
  13:	02 
  14:	0f                   	.byte 0xf
  15:	94                   	xchg   %eax,%esp
[    5.764999][    C0] RSP: 0000:ffffc90000003e30 EFLAGS: 00010202
[    5.764999][    C0] RAX: 0000000000000001 RBX: ffff8881002c2ba0 RCX: 0000000000000000
[    5.764999][    C0] RDX: ffff8881002dbc01 RSI: 00000000000000c0 RDI: 00000000000000c0
[    5.764999][    C0] RBP: 0000000000000000 R08: ffff8881002dbcc0 R09: ffff8881002c2020
[    5.764999][    C0] R10: 00ffffff00000000 R11: 0000000000000000 R12: 0000000000000000
[    5.764999][    C0] R13: ffffc90000003ed8 R14: ffffc90000003e80 R15: ffffc90000003f4c
[    5.764999][    C0] FS:  0000000000000000(0000) GS:ffff888ccb7f2000(0000) knlGS:0000000000000000
[    5.764999][    C0] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    5.764999][    C0] CR2: 0000000000000000 CR3: 0000002c7de24001 CR4: 00000000007706f0
[    5.764999][    C0] PKRU: 55555554
[    5.764999][    C0] Call Trace:
[    5.764999][    C0]  <IRQ>
[    5.764999][    C0]  ? rcu_do_batch (kernel/rcu/tree.c:2612 (discriminator 1))
[    5.764999][    C0]  sched_balance_domains (kernel/sched/fair.c:12186 (discriminator 1))
[    5.764999][    C0]  ? sched_balance_update_blocked_averages (arch/x86/include/asm/irqflags.h:158 (discriminator 1) kernel/sched/sched.h:1577 (discriminator 1) kernel/sched/sched.h:1884 (discriminator 1) kernel/sched/fair.c:9857 (discriminator 1))
[    5.764999][    C0]  handle_softirqs (arch/x86/include/asm/jump_label.h:36 include/trace/events/irq.h:142 kernel/softirq.c:623)
[    5.764999][    C0]  __irq_exit_rcu (kernel/softirq.c:657 kernel/softirq.c:496 kernel/softirq.c:723)
[    5.764999][    C0]  sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1052 (discriminator 35) arch/x86/kernel/apic/apic.c:1052 (discriminator 35))
[    5.764999][    C0]  </IRQ>
[    5.764999][    C0]  <TASK>
[    5.764999][    C0]  asm_sysvec_apic_timer_interrupt (arch/x86/include/asm/idtentry.h:697)
[    5.764999][    C0] RIP: 0010:mwait_idle (arch/x86/include/asm/irqflags.h:37 arch/x86/include/asm/irqflags.h:114 arch/x86/kernel/process.c:930)
[    5.764999][    C0] Code: 2d c0 8e 10 00 f0 80 0e 40 48 8b 06 a8 10 75 1b 48 89 f0 0f 1f 00 31 c9 89 ca 0f 01 c8 48 8b 06 a8 10 75 07 89 c8 fb 0f 01 c9 <fa> f0 80 26 bf e9 c5 e1 00 00 0f 1f 44 00 00 66 66 2e 0f 1f 84 00
All code
========
   0:	2d c0 8e 10 00       	sub    $0x108ec0,%eax
   5:	f0 80 0e 40          	lock orb $0x40,(%rsi)
   9:	48 8b 06             	mov    (%rsi),%rax
   c:	a8 10                	test   $0x10,%al
   e:	75 1b                	jne    0x2b
  10:	48 89 f0             	mov    %rsi,%rax
  13:	0f 1f 00             	nopl   (%rax)
  16:	31 c9                	xor    %ecx,%ecx
  18:	89 ca                	mov    %ecx,%edx
  1a:	0f 01 c8             	monitor %rax,%ecx,%edx
  1d:	48 8b 06             	mov    (%rsi),%rax
  20:	a8 10                	test   $0x10,%al
  22:	75 07                	jne    0x2b
  24:	89 c8                	mov    %ecx,%eax
  26:	fb                   	sti
  27:	0f 01 c9             	mwait  %eax,%ecx
  2a:*	fa                   	cli		<-- trapping instruction
  2b:	f0 80 26 bf          	lock andb $0xbf,(%rsi)
  2f:	e9 c5 e1 00 00       	jmp    0xe1f9
  34:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  39:	66                   	data16
  3a:	66                   	data16
  3b:	2e                   	cs
  3c:	0f                   	.byte 0xf
  3d:	1f                   	(bad)
  3e:	84 00                	test   %al,(%rax)

Code starting with the faulting instruction
===========================================
   0:	fa                   	cli
   1:	f0 80 26 bf          	lock andb $0xbf,(%rsi)
   5:	e9 c5 e1 00 00       	jmp    0xe1cf
   a:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
   f:	66                   	data16
  10:	66                   	data16
  11:	2e                   	cs
  12:	0f                   	.byte 0xf
  13:	1f                   	(bad)
  14:	84 00                	test   %al,(%rax)
[    5.764999][    C0] RSP: 0000:ffffffff82e03e90 EFLAGS: 00000246
[    5.764999][    C0] RAX: 0000000000000000 RBX: ffffffff82e12940 RCX: 0000000000000000
[    5.764999][    C0] RDX: 0000000000000000 RSI: ffffffff82e12940 RDI: 0000000001655ddc
[    5.764999][    C0] RBP: 0000000000000000 R08: 0000000000000000 R09: ffff888105016728
[    5.764999][    C0] R10: 000000000000001d R11: 0000000000000011 R12: 0000000000000000
[    5.764999][    C0] R13: 0000000000000000 R14: 0000000000000000 R15: 0000002c7fff1000
[    5.764999][    C0]  default_idle_call (include/linux/cpuidle.h:144 kernel/sched/idle.c:123)
[    5.764999][    C0]  cpuidle_idle_call (kernel/sched/idle.c:191)
[    5.764999][    C0]  do_idle (kernel/sched/idle.c:332)
[    5.764999][    C0]  cpu_startup_entry (kernel/sched/idle.c:427)
[    5.764999][    C0]  rest_init (init/main.c:757)
[    5.764999][    C0]  start_kernel (init/main.c:1111)
[    5.764999][    C0]  x86_64_start_reservations (arch/x86/kernel/head64.c:310)
[    5.764999][    C0]  x86_64_start_kernel (??:?)
[    5.764999][    C0]  common_startup_64 (arch/x86/kernel/head_64.S:419)
[    5.764999][    C0]  </TASK>
[    5.764999][    C0] Modules linked in:
[    5.764999][    C0] CR2: 0000000000000000
[    5.764999][    C0] ---[ end trace 0000000000000000 ]---


The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20251127/202511271605.bd46ddc3-lkp@intel.com



-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [tip:tmp.tmp] [sched/fair] eb2db043ab: BUG:kernel_NULL_pointer_dereference,address

[Peter Zijlstra]

On Thu, Nov 27, 2025 at 04:35:37PM +0800, kernel test robot wrote:
> 
> 
> Hello,
> 
> kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on:
> 
> commit: eb2db043ab3a28ae76800f2a57e144420800d56d ("sched/fair: Skip sched_balance_running cmpxchg when balance is not due")
> https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git tmp.tmp

Not sure what this branch is, but tip/sched/core has the fixed commit.

Re: [tip:tmp.tmp] [sched/fair] eb2db043ab: BUG:kernel_NULL_pointer_dereference,address

[Ingo Molnar]

* Peter Zijlstra <peterz@infradead.org> wrote:

> On Thu, Nov 27, 2025 at 04:35:37PM +0800, kernel test robot wrote:
> > 
> > 
> > Hello,
> > 
> > kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on:
> > 
> > commit: eb2db043ab3a28ae76800f2a57e144420800d56d ("sched/fair: Skip sched_balance_running cmpxchg when balance is not due")
> > https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git tmp.tmp
> 
> Not sure what this branch is, but tip/sched/core has the fixed commit.

Not sure how the test-bot picked up this temporary 
branch and reported it despite it being gone from the 
repo, but the branch hasn't been in -tip for days.

This report can be safely ignored.

Thanks,

	Ingo

Re: [tip:tmp.tmp] [sched/fair] eb2db043ab: BUG:kernel_NULL_pointer_dereference,address

[Oliver Sang]

hi,

On Thu, Nov 27, 2025 at 10:07:28AM +0100, Ingo Molnar wrote:
> 
> * Peter Zijlstra <peterz@infradead.org> wrote:
> 
> > On Thu, Nov 27, 2025 at 04:35:37PM +0800, kernel test robot wrote:
> > > 
> > > 
> > > Hello,
> > > 
> > > kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on:
> > > 
> > > commit: eb2db043ab3a28ae76800f2a57e144420800d56d ("sched/fair: Skip sched_balance_running cmpxchg when balance is not due")
> > > https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git tmp.tmp
> > 
> > Not sure what this branch is, but tip/sched/core has the fixed commit.
> 
> Not sure how the test-bot picked up this temporary 
> branch and reported it despite it being gone from the 
> repo, but the branch hasn't been in -tip for days.
> 
> This report can be safely ignored.

sorry for the noise. yeah, our so-called 'gitmirror' mechnism fetched the
tmp.tmp branch about 10 days ago, then it merged into our hourly kernel to
be running tests. so it's kind of 'stored' in our repo.

since the bad commit caused crash issue on various test machines, we made out
the report, but missed the check of whether branch is still existing remotely.

we will refine our code/process to avoid this kind of meaningless report.

thanks

> 
> Thanks,
> 
> 	Ingo
> 

Re: [tip:tmp.tmp] [sched/fair] eb2db043ab: BUG:kernel_NULL_pointer_dereference,address

[Peter Zijlstra]

On Fri, Nov 28, 2025 at 09:42:04AM +0800, Oliver Sang wrote:
> hi,
> 
> On Thu, Nov 27, 2025 at 10:07:28AM +0100, Ingo Molnar wrote:
> > 
> > * Peter Zijlstra <peterz@infradead.org> wrote:
> > 
> > > On Thu, Nov 27, 2025 at 04:35:37PM +0800, kernel test robot wrote:
> > > > 
> > > > 
> > > > Hello,
> > > > 
> > > > kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on:
> > > > 
> > > > commit: eb2db043ab3a28ae76800f2a57e144420800d56d ("sched/fair: Skip sched_balance_running cmpxchg when balance is not due")
> > > > https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git tmp.tmp
> > > 
> > > Not sure what this branch is, but tip/sched/core has the fixed commit.
> > 
> > Not sure how the test-bot picked up this temporary 
> > branch and reported it despite it being gone from the 
> > repo, but the branch hasn't been in -tip for days.
> > 
> > This report can be safely ignored.
> 
> sorry for the noise. yeah, our so-called 'gitmirror' mechnism fetched the
> tmp.tmp branch about 10 days ago, then it merged into our hourly kernel to
> be running tests. so it's kind of 'stored' in our repo.
> 
> since the bad commit caused crash issue on various test machines, we made out
> the report, but missed the check of whether branch is still existing remotely.
> 
> we will refine our code/process to avoid this kind of meaningless report.

Might it make sense to exclude all branches named tmp ? IIRC there are
some patterns that the robot skips over, but I forever forget what they
are :/

Re: [tip:tmp.tmp] [sched/fair] eb2db043ab: BUG:kernel_NULL_pointer_dereference,address

[Ingo Molnar]

* Peter Zijlstra <peterz@infradead.org> wrote:

> On Fri, Nov 28, 2025 at 09:42:04AM +0800, Oliver Sang wrote:
> > hi,
> > 
> > On Thu, Nov 27, 2025 at 10:07:28AM +0100, Ingo Molnar wrote:
> > > 
> > > * Peter Zijlstra <peterz@infradead.org> wrote:
> > > 
> > > > On Thu, Nov 27, 2025 at 04:35:37PM +0800, kernel test robot wrote:
> > > > > 
> > > > > 
> > > > > Hello,
> > > > > 
> > > > > kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on:
> > > > > 
> > > > > commit: eb2db043ab3a28ae76800f2a57e144420800d56d ("sched/fair: Skip sched_balance_running cmpxchg when balance is not due")
> > > > > https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git tmp.tmp
> > > > 
> > > > Not sure what this branch is, but tip/sched/core has the fixed commit.
> > > 
> > > Not sure how the test-bot picked up this temporary 
> > > branch and reported it despite it being gone from the 
> > > repo, but the branch hasn't been in -tip for days.
> > > 
> > > This report can be safely ignored.
> > 
> > sorry for the noise. yeah, our so-called 'gitmirror' mechnism fetched the
> > tmp.tmp branch about 10 days ago, then it merged into our hourly kernel to
> > be running tests. so it's kind of 'stored' in our repo.
> > 
> > since the bad commit caused crash issue on various test machines, we made out
> > the report, but missed the check of whether branch is still existing remotely.
> > 
> > we will refine our code/process to avoid this kind of meaningless report.
> 
> Might it make sense to exclude all branches named tmp ?

So the tmpfs project might disagree. ;-)

But a '^tmp\.' prefix exclusion pattern should be 
pretty robust IMO.

> [...] IIRC there are some patterns that the robot 
> skips over, but I forever forget what they are :/

I'm curious about those patterns, although 99% of the 
time I'm *happy* when the LKP robot finds a new 
development branch that I pushed out, quite often it 
will find bugs that my own testing doesn't catch, and 
the reports are useful & relevant these days. Beyond 
the bugreports the 'SUCCESS' reports are useful as 
well, as they can be used to phase the flow of 
development commits. So no complaints from me.

This tmp.tmp case was an exception to the rule really, 
and given the overwhelmingly positive net utility of 
the LKP test-bot I'd just ignore it, especially since 
the LKP bot was technically correct and the crashes 
were real (albeit fixed already).

Thanks,

	Ingo

Re: [tip:tmp.tmp] [sched/fair] eb2db043ab: BUG:kernel_NULL_pointer_dereference,address

[Oliver Sang]

hi, Ingo Molnar, hi, Peter Zijlstra,

On Tue, Dec 02, 2025 at 06:11:36AM +0100, Ingo Molnar wrote:
> 
> * Peter Zijlstra <peterz@infradead.org> wrote:
> 
> > On Fri, Nov 28, 2025 at 09:42:04AM +0800, Oliver Sang wrote:
> > > hi,
> > > 
> > > On Thu, Nov 27, 2025 at 10:07:28AM +0100, Ingo Molnar wrote:
> > > > 
> > > > * Peter Zijlstra <peterz@infradead.org> wrote:
> > > > 
> > > > > On Thu, Nov 27, 2025 at 04:35:37PM +0800, kernel test robot wrote:
> > > > > > 
> > > > > > 
> > > > > > Hello,
> > > > > > 
> > > > > > kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on:
> > > > > > 
> > > > > > commit: eb2db043ab3a28ae76800f2a57e144420800d56d ("sched/fair: Skip sched_balance_running cmpxchg when balance is not due")
> > > > > > https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git tmp.tmp
> > > > > 
> > > > > Not sure what this branch is, but tip/sched/core has the fixed commit.
> > > > 
> > > > Not sure how the test-bot picked up this temporary 
> > > > branch and reported it despite it being gone from the 
> > > > repo, but the branch hasn't been in -tip for days.
> > > > 
> > > > This report can be safely ignored.
> > > 
> > > sorry for the noise. yeah, our so-called 'gitmirror' mechnism fetched the
> > > tmp.tmp branch about 10 days ago, then it merged into our hourly kernel to
> > > be running tests. so it's kind of 'stored' in our repo.
> > > 
> > > since the bad commit caused crash issue on various test machines, we made out
> > > the report, but missed the check of whether branch is still existing remotely.
> > > 
> > > we will refine our code/process to avoid this kind of meaningless report.
> > 
> > Might it make sense to exclude all branches named tmp ?
> 
> So the tmpfs project might disagree. ;-)
> 
> But a '^tmp\.' prefix exclusion pattern should be 
> pretty robust IMO.
> 
> > [...] IIRC there are some patterns that the robot 
> > skips over, but I forever forget what they are :/
> 
> I'm curious about those patterns, although 99% of the 
> time I'm *happy* when the LKP robot finds a new 
> development branch that I pushed out, quite often it 
> will find bugs that my own testing doesn't catch, and 
> the reports are useful & relevant these days. Beyond 
> the bugreports the 'SUCCESS' reports are useful as 
> well, as they can be used to phase the flow of 
> development commits. So no complaints from me.
> 
> This tmp.tmp case was an exception to the rule really, 
> and given the overwhelmingly positive net utility of 
> the LKP test-bot I'd just ignore it, especially since 
> the LKP bot was technically correct and the crashes 
> were real (albeit fixed already).

we do have some default pattern for branches to ignore:
default_branch_denylist: (.*experimental.*|.*dont-build|origin/.*|remotes/.*|.*/orphan-.*)
(https://github.com/intel/lkp-tests/blob/master/repo/linux/DEFAULTS#L5)

but we also support repo specific configurations. such like for tip:
branch_denylist: auto-.*|tmp.*|base-.*|test.*|.*-for-linus|tip
(https://github.com/intel/lkp-tests/blob/master/repo/linux/tip#L19)

the "tmp.*" is just updated from previous "tmp-.*" to cover tmp.tmp
(https://github.com/intel/lkp-tests/commit/acd36193a0dd2bbc1c6d4ef59dd2b33a2eece3e0)

thanks

> 
> Thanks,
> 
> 	Ingo
> 

Re: [tip:tmp.tmp] [sched/fair] eb2db043ab: BUG:kernel_NULL_pointer_dereference,address

[Ingo Molnar]

* Oliver Sang <oliver.sang@intel.com> wrote:

> we do have some default pattern for branches to ignore:
> default_branch_denylist: (.*experimental.*|.*dont-build|origin/.*|remotes/.*|.*/orphan-.*)
> (https://github.com/intel/lkp-tests/blob/master/repo/linux/DEFAULTS#L5)
> 
> but we also support repo specific configurations. such like for tip:
> branch_denylist: auto-.*|tmp.*|base-.*|test.*|.*-for-linus|tip
> (https://github.com/intel/lkp-tests/blob/master/repo/linux/tip#L19)

That's useful to know, thanks!

> the "tmp.*" is just updated from previous "tmp-.*" to cover tmp.tmp
> (https://github.com/intel/lkp-tests/commit/acd36193a0dd2bbc1c6d4ef59dd2b33a2eece3e0)

Thank you for the change, and LOL, I *swear* I didn't name it
tmp.tmp just to break the pattern. ;-)

Thanks,

	Ingo

Re: [tip:tmp.tmp] [sched/fair] eb2db043ab: BUG:kernel_NULL_pointer_dereference,address

[Ingo Molnar]

* Oliver Sang <oliver.sang@intel.com> wrote:

> hi,
> 
> On Thu, Nov 27, 2025 at 10:07:28AM +0100, Ingo Molnar wrote:
> > 
> > * Peter Zijlstra <peterz@infradead.org> wrote:
> > 
> > > On Thu, Nov 27, 2025 at 04:35:37PM +0800, kernel test robot wrote:
> > > > 
> > > > 
> > > > Hello,
> > > > 
> > > > kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on:
> > > > 
> > > > commit: eb2db043ab3a28ae76800f2a57e144420800d56d ("sched/fair: Skip sched_balance_running cmpxchg when balance is not due")
> > > > https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git tmp.tmp
> > > 
> > > Not sure what this branch is, but tip/sched/core has the fixed commit.
> > 
> > Not sure how the test-bot picked up this temporary 
> > branch and reported it despite it being gone from the 
> > repo, but the branch hasn't been in -tip for days.
> > 
> > This report can be safely ignored.
> 
> sorry for the noise. yeah, our so-called 'gitmirror' mechnism fetched the
> tmp.tmp branch about 10 days ago, then it merged into our hourly kernel to
> be running tests. so it's kind of 'stored' in our repo.
>
> since the bad commit caused crash issue on various test machines, we made out
> the report, but missed the check of whether branch is still existing remotely.
>
> we will refine our code/process to avoid this kind of meaningless report.

Thank you, much appreciated!

	Ingo