WARNING in __set_cpus_allowed_ptr_locked

Status: upstream: reported C repro on 2026/09/03 06:54
Subsystems: kernel
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+6835d5c11145e4f77057@syzkaller.appspotmail.com
First crash: 4d05h, last: 3d16h
Cause bisection: failed (error log, bisect log)
  
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ID Workflow Result Correct Bug Created Started Finished Revision
e6c546ad assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in __set_cpus_allowed_ptr_locked 2026/08/31 00:00 2026/08/31 00:00 2026/08/31 00:56 2f52988a
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Title Replies (including bot) Last reply
[syzbot] [kernel?] WARNING in __set_cpus_allowed_ptr_locked 0 (1) 2026/09/03 06:54

Sample crash report:
------------[ cut here ]------------
!pending
WARNING: kernel/sched/core.c:3057 at affine_move_task kernel/sched/core.c:3057 [inline], CPU#0: irq/33-virtio1-/1195
WARNING: kernel/sched/core.c:3057 at __set_cpus_allowed_ptr_locked+0x10ff/0x19c0 kernel/sched/core.c:3190, CPU#0: irq/33-virtio1-/1195
Modules linked in:
CPU: 0 UID: 0 PID: 1195 Comm: irq/33-virtio1- Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:affine_move_task kernel/sched/core.c:3057 [inline]
RIP: 0010:__set_cpus_allowed_ptr_locked+0x10ff/0x19c0 kernel/sched/core.c:3190
Code: cf ff ff 48 8b 5c 24 18 48 8d 7b 08 e8 9a 93 09 00 e9 2e fe ff ff 90 0f 0b 90 e9 74 f3 ff ff e8 b7 ee 9d ff e9 dd f8 ff ff 90 <0f> 0b 90 48 8b 3c 24 48 8b 74 24 08 48 8b 54 24 10 e8 2b cf ff ff
RSP: 0018:ffffc9000681f900 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880267a84b8 RCX: ffffffff81950a2b
RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffff8880267a84b0
RBP: ffffc9000681fb10 R08: ffff8880267a84b7 R09: 1ffff11004cf5096
R10: dffffc0000000000 R11: ffffed1004cf5097 R12: 1ffff11004cf5097
R13: 1ffff92000d03f28 R14: ffff8880267a84b0 R15: 0000000000000004
FS:  0000000000000000(0000) GS:ffff888125bd6000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555581c3f6d0 CR3: 0000000043f1e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __set_cpus_allowed_ptr kernel/sched/core.c:3222 [inline]
 ___migrate_enable+0x19c/0x1f0 kernel/sched/core.c:2486
 __migrate_enable include/linux/sched.h:2471 [inline]
 migrate_enable include/linux/sched.h:2520 [inline]
 __local_bh_enable+0x21c/0x2f0 kernel/softirq.c:273
 __local_bh_enable_ip+0x19f/0x2b0 kernel/softirq.c:328
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 irq_forced_thread_fn+0xe9/0x120 kernel/irq/manage.c:1169
 irq_thread+0x455/0x690 kernel/irq/manage.c:1272
 kthread+0x38b/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/30 19:22 upstream 08dbfad3f504 2f52988a .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in __set_cpus_allowed_ptr_locked
2026/08/30 15:40 upstream 08dbfad3f504 2f52988a .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in __set_cpus_allowed_ptr_locked
2026/08/30 06:49 upstream 08dbfad3f504 2f52988a .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in __set_cpus_allowed_ptr_locked
* Struck through repros no longer work on HEAD.