syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (29 ticks this GP) idle=c004/1/0x4000000000000000 softirq=76056/76057 fqs=15
	(detected by 0, t=10502 jiffies, g=139869, q=323 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 15947 Comm: syz.7.2910 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:-1 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3793 [inline]
RIP: 0010:__lock_acquire+0x1408/0x7d10 kernel/locking/lockdep.c:5049
Code: 3a 4b 0f 72 25 48 c7 c0 40 11 c0 96 48 c1 e8 03 42 0f b6 04 00 84 c0 0f 85 89 5a 00 00 83 3d be a9 5b 15 00 0f 84 f0 03 00 00 <48> b8 eb 83 b5 80 46 86 c8 61 49 0f af c6 48 c1 e8 2d 4c 8d 24 c5
RSP: 0018:ffffc900001e08a0 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff8164674f
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90afa240
RBP: ffffc900001e0af0 R08: dffffc0000000000 R09: 1ffffffff215f448
R10: dffffc0000000000 R11: fffffbfff215f449 R12: 89dc7d52f036ca20
R13: 000000006873d69d R14: 89dc7d52f036ca20 R15: ffff888029288ad0
FS:  00007f21045876c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f99c0e92b4c CR3: 000000005d06e000 CR4: 00000000003526e0
Call Trace:
 <IRQ>
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162
 debug_object_deactivate+0x62/0x390 lib/debugobjects.c:753
 debug_hrtimer_deactivate kernel/time/hrtimer.c:453 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1715 [inline]
 __hrtimer_run_queues+0x2d5/0xd50 kernel/time/hrtimer.c:1811
 hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1873
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:unwind_next_frame+0x7/0x20b0 arch/x86/kernel/unwind_orc.c:423
Code: 5f c3 89 d9 80 e1 07 80 c1 03 38 c1 7c 97 48 89 df e8 bd 68 9a 00 eb 8d 66 2e 0f 1f 84 00 00 00 00 00 90 55 41 57 41 56 41 55 <41> 54 53 48 81 ec a0 00 00 00 48 89 fb 49 be 00 00 00 00 00 fc ff
RSP: 0018:ffffc90003476e60 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffc90003476f40 RCX: 0000000080000000
RDX: dffffc0000000000 RSI: ffffffff81d09e13 RDI: ffffc90003476e88
RBP: ffffc90003476f10 R08: ffffc90003476f50 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200068eddd R12: ffff888029288000
R13: 1ffff110052510ae R14: ffffffff81713430 R15: ffffc90003476e88
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
 save_stack+0x121/0x230 mm/page_owner.c:127
 __set_page_owner+0x19/0x60 mm/page_owner.c:190
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2559
 prep_new_page mm/page_alloc.c:2566 [inline]
 get_page_from_freelist+0x1a1e/0x1ab0 mm/page_alloc.c:4357
 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5657
 __folio_alloc+0xe/0x30 mm/page_alloc.c:5689
 vma_alloc_folio+0x4a3/0x900 mm/mempolicy.c:2243
 shmem_alloc_folio mm/shmem.c:1589 [inline]
 shmem_alloc_and_acct_folio+0x463/0xbc0 mm/shmem.c:1613
 shmem_get_folio_gfp+0x1361/0x3400 mm/shmem.c:1941
 shmem_fault+0x1b6/0x780 mm/shmem.c:2156
 __do_fault+0x13b/0x4e0 mm/memory.c:4278
 do_read_fault mm/memory.c:4629 [inline]
 do_fault mm/memory.c:4758 [inline]
 handle_pte_fault mm/memory.c:5029 [inline]
 __handle_mm_fault mm/memory.c:5171 [inline]
 handle_mm_fault+0x2407/0x3ee0 mm/memory.c:5292
 faultin_page mm/gup.c:1026 [inline]
 __get_user_pages+0x40d/0xec0 mm/gup.c:1250
 populate_vma_page_range+0x214/0x2b0 mm/gup.c:1607
 __mm_populate+0x25c/0x380 mm/gup.c:1721
 mm_populate include/linux/mm.h:2891 [inline]
 vm_mmap_pgoff+0x212/0x2d0 mm/util.c:525
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f210379ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2104587028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f2103a15fa0 RCX: 00007f210379ce59
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007f2103832d6f R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2103a16038 R14: 00007f2103a15fa0 R15: 00007ffc5a910348
 </TASK>
rcu: rcu_preempt kthread starved for 10472 jiffies! g139869 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:27696 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x303/0x1340 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 5792 Comm: kworker/u4:10 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:424 [inline]
RIP: 0010:smp_call_function_many_cond+0xeb9/0x1290 kernel/smp.c:998
Code: 00 00 00 00 00 fc ff df 75 07 e8 82 f3 0a 00 eb 37 f3 90 41 0f b6 04 1c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 67 f3 0a 00 <eb> e5 44 89 f9 80 e1 07 80 c1 03 38 c1 7c e3 4c 89 ff e8 80 ff 5b
RSP: 0018:ffffc9000c827800 EFLAGS: 00000293
RAX: ffffffff81779349 RBX: dffffc0000000000 RCX: ffff88802431d940
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000c827960 R08: ffffffff90afa247 R09: 1ffffffff215f448
R10: dffffc0000000000 R11: fffffbfff215f449 R12: 1ffff110171e81d9
R13: ffff8880b8e3bbc0 R14: 0000000000000001 R15: ffff8880b8f40ec8
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff63f05ff0 CR3: 000000000c88e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1165
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:1574 [inline]
 text_poke_bp_batch+0x2b7/0x850 arch/x86/kernel/alternative.c:1774
 text_poke_flush arch/x86/kernel/alternative.c:1965 [inline]
 text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1972
 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x11f/0x240 kernel/jump_label.c:207
 static_key_enable+0x16/0x20 kernel/jump_label.c:220
 toggle_allocation_gate+0xba/0x470 mm/kfence/core.c:821
 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>