syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9057/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=25725, q=655 ncpus=2)
task:syz.3.594       state:R  running task     stack:23624 pid:9057  tgid:9057  ppid:5841   task_flags:0x40064c flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288
 irqentry_exit+0x36/0x90 kernel/entry/common.c:197
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5872
Code: 67 3e 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 62 6c 13 0f 0f 82 74 02 00 00 8b 35 2a 9e 13 0f 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 b9 66 3e 12 0f 85 c7 02 00 00 48 83 c4
RSP: 0018:ffffc90004a1f4e0 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e5c11e0 RCX: 000000009ccb6cf7
RDX: 0000000000000000 RSI: ffffffff8de29c00 RDI: ffffffff8c162400
RBP: 0000000000000002 R08: 9db3e1ba819abd31 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 ___pte_offset_map+0x44/0x4f0 mm/pgtable-generic.c:286
 __pte_offset_map include/linux/mm.h:3014 [inline]
 __pte_offset_map_lock+0x8d/0x310 mm/pgtable-generic.c:397
 pte_offset_map_lock include/linux/mm.h:3029 [inline]
 zap_pte_range mm/memory.c:1712 [inline]
 zap_pmd_range mm/memory.c:1818 [inline]
 zap_pud_range mm/memory.c:1847 [inline]
 zap_p4d_range mm/memory.c:1868 [inline]
 unmap_page_range+0xacf/0x42c0 mm/memory.c:1889
 unmap_single_vma.constprop.0+0x153/0x240 mm/memory.c:1932
 unmap_vmas+0x218/0x470 mm/memory.c:1976
 exit_mmap+0x1b9/0xb90 mm/mmap.c:1280
 __mmput+0x12a/0x410 kernel/fork.c:1130
 mmput+0x62/0x70 kernel/fork.c:1152
 exit_mm kernel/exit.c:582 [inline]
 do_exit+0x7c7/0x2bf0 kernel/exit.c:949
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 get_signal+0x2673/0x26d0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:40 [inline]
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 irqentry_exit_to_user_mode+0x12a/0x270 kernel/entry/common.c:73
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f25f9b8ebf1
RSP: 002b:fffffffffffffe70 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f25f9db6270 RCX: 00007f25f9b8ebe9
RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000
RBP: 00007f25f9c11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f25f9db6308 R14: 00007f25f9db6270 R15: 00007ffd74cc6288
 </TASK>
rcu: rcu_preempt kthread starved for 10484 jiffies! g25725 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:28616 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 9070 Comm: syz.0.603 Not tainted 6.17.0-rc1-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline]
RIP: 0010:lock_acquire+0x2c8/0x350 kernel/locking/lockdep.c:5831
Code: 8b 05 dc 9b 13 0f 85 c0 0f 85 b6 fd ff ff b9 0a 00 00 00 ba 08 00 00 00 48 8d 74 24 08 48 89 df e8 ad cb ff ff e9 9a fd ff ff <e8> 83 e7 08 00 84 c0 0f 85 7f fd ff ff 80 3d 34 ba fb 0e 00 0f 85
RSP: 0018:ffffc90000a08c90 EFLAGS: 00000097
RAX: 0000000000000001 RBX: ffffffff9b0df810 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff9b0df810
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff9b0df7f8 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fd2cee386c0(0000) GS:ffff8881247bd000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000561600595300 CR3: 000000007b7d2000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
 debug_object_activate+0x14c/0x4c0 lib/debugobjects.c:818
 debug_hrtimer_activate kernel/time/hrtimer.c:445 [inline]
 debug_activate kernel/time/hrtimer.c:484 [inline]
 enqueue_hrtimer+0x23/0x3b0 kernel/time/hrtimer.c:1088
 __run_hrtimer kernel/time/hrtimer.c:1778 [inline]
 __hrtimer_run_queues+0x8ff/0xad0 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:finish_task_switch.isra.0+0x22a/0xc10 kernel/sched/core.c:5225
Code: fb 09 00 00 44 8b 05 69 5c 22 0f 45 85 c0 0f 85 be 01 00 00 4c 89 e7 e8 a4 f6 ff ff e8 bf 6e 3a 00 fb 65 48 8b 1d fe 24 4d 12 <48> 8d bb 18 16 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1
RSP: 0018:ffffc90003e9f6f0 EFLAGS: 00000206
RAX: 0000000000005095 RBX: ffff88802f29c880 RCX: ffffffff81c378cf
RDX: 0000000000000000 RSI: ffffffff8de4f0f5 RDI: ffffffff8c162400
RBP: ffffc90003e9f738 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90ab3597 R11: 0000000000000000 R12: ffff8880b853a300
R13: ffff88801e2ea440 R14: ffff8880b843a300 R15: ffff8880b853b170
 context_switch kernel/sched/core.c:5360 [inline]
 __schedule+0x1198/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common+0x2fc/0x4e0 kernel/sched/completion.c:121
 rdmsr_safe_on_cpu+0x1dc/0x210 arch/x86/lib/msr-smp.c:181
 msr_read+0x19d/0x250 arch/x86/kernel/msr.c:66
 vfs_read+0x1e1/0xcf0 fs/read_write.c:570
 ksys_read+0x12a/0x250 fs/read_write.c:715
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd2cdf8ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd2cee38038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fd2ce1b5fa0 RCX: 00007fd2cdf8ebe9
RDX: 0000000000018ff8 RSI: 0000200000019680 RDI: 0000000000000006
RBP: 00007fd2ce011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd2ce1b6038 R14: 00007fd2ce1b5fa0 R15: 00007fffd0fd6438
 </TASK>