[peterz-queue:sched/flat] [sched/eevdf] d464c12d2d: Oops:divide_error:#[##]

[peterz-queue:sched/flat] [sched/eevdf] d464c12d2d: Oops:divide_error:#[##]

[kernel test robot]

Hello,

kernel test robot noticed "Oops:divide_error:#[##]" on:

commit: d464c12d2d0562f4cc32bd0e62fad20f0d87e9ff ("sched/eevdf: Move to a single runqueue")
https://git.kernel.org/cgit/linux/kernel/git/peterz/queue.git sched/flat

in testcase: boot

config: x86_64-randconfig-005-20260514
compiler: clang-20
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 32G

(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/202605201620.d44e2cd6-lkp@intel.com



[   16.137634][  T102] Oops: divide error: 0000 [#1]
[   16.139003][  T102] CPU: 0 UID: 0 PID: 102 Comm: udevd Tainted: G                T   7.1.0-rc2+ #1 PREEMPT
[   16.142054][  T102] Tainted: [T]=RANDSTRUCT
[   16.143709][  T102] RIP: 0010:update_protect_slice (kbuild/src/kernel/sched/fair.c:290 kbuild/src/kernel/sched/fair.c:300 kbuild/src/kernel/sched/fair.c:1070)
[   16.145953][  T102] Code: 49 48 48 39 c8 48 0f 43 c1 48 8b 8e 98 00 00 00 4c 8b 46 10 48 8b be 88 00 00 00 49 81 f8 00 00 10 00 74 09 48 c1 e0 14 31 d2 <49> f7 f0 48 01 f8 48 39 c8 48 0f 49 c1 48 89 86 98 00 00 00 c3 cc
All code
========
   0:	49                   	rex.WB
   1:	48                   	rex.W
   2:	48 39 c8             	cmp    %rcx,%rax
   5:	48 0f 43 c1          	cmovae %rcx,%rax
   9:	48 8b 8e 98 00 00 00 	mov    0x98(%rsi),%rcx
  10:	4c 8b 46 10          	mov    0x10(%rsi),%r8
  14:	48 8b be 88 00 00 00 	mov    0x88(%rsi),%rdi
  1b:	49 81 f8 00 00 10 00 	cmp    $0x100000,%r8
  22:	74 09                	je     0x2d
  24:	48 c1 e0 14          	shl    $0x14,%rax
  28:	31 d2                	xor    %edx,%edx
  2a:*	49 f7 f0             	div    %r8		<-- trapping instruction
  2d:	48 01 f8             	add    %rdi,%rax
  30:	48 39 c8             	cmp    %rcx,%rax
  33:	48 0f 49 c1          	cmovns %rcx,%rax
  37:	48 89 86 98 00 00 00 	mov    %rax,0x98(%rsi)
  3e:	c3                   	ret
  3f:	cc                   	int3

Code starting with the faulting instruction
===========================================
   0:	49 f7 f0             	div    %r8
   3:	48 01 f8             	add    %rdi,%rax
   6:	48 39 c8             	cmp    %rcx,%rax
   9:	48 0f 49 c1          	cmovns %rcx,%rax
   d:	48 89 86 98 00 00 00 	mov    %rax,0x98(%rsi)
  14:	c3                   	ret
  15:	cc                   	int3
[   16.153728][  T102] RSP: 0000:ffff888130197c10 EFLAGS: 00010046
[   16.156049][  T102] RAX: 000000aae6000000 RBX: ffffffff836824c0 RCX: 0000000000000000
[   16.159060][  T102] RDX: 0000000000000000 RSI: ffffffff83628140 RDI: 0000000000000000
[   16.161885][  T102] RBP: ffff888130197c30 R08: 0000000000000000 R09: 0000000369497ec6
[   16.163874][  T102] R10: 0000000000000000 R11: ffffffff813a0700 R12: ffffffff83682520
[   16.165864][  T102] R13: 0000000000004261 R14: ffff88812ffaa000 R15: ffffffff83626cc0
[   16.167651][  T102] FS:  0000000000000000(0000) GS:0000000000000000(0063) knlGS:00000000f7cb9740
[   16.169702][  T102] CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
[   16.171179][  T102] CR2: 00000000f7c3700c CR3: 0000000130150000 CR4: 00000000000406b0
[   16.173009][  T102] Call Trace:
[   16.173803][  T102]  <TASK>
[   16.174479][  T102]  wakeup_preempt (kbuild/src/kernel/sched/core.c:2256)
[   16.175457][  T102]  attach_one_task (kbuild/src/kernel/sched/sched.h:3027)
[   16.176470][  T102]  find_proxy_task (kbuild/src/kernel/sched/core.c:6800)
[   16.177605][  T102]  __schedule (kbuild/src/kernel/sched/core.c:7108)


The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20260520/202605201620.d44e2cd6-lkp@intel.com



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