syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (39 ticks this GP) idle=6f7/1/0x4000000000000000 softirq=11507/11507 fqs=0 
	(detected by 1, t=10502 jiffies, g=17121, q=456)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5741 Comm: syz.1.297 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
RIP: 0010:atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:512 [inline]
RIP: 0010:queued_spin_lock include/asm-generic/qspinlock.h:82 [inline]
RIP: 0010:do_raw_spin_lock+0x119/0x2f0 kernel/locking/spinlock_debug.c:115
Code: 45 ac a3 7e 39 c8 0f 84 27 01 00 00 41 c6 44 14 04 04 c7 44 24 40 00 00 00 00 48 89 df be 04 00 00 00 49 89 d6 e8 47 ed 5f 00 <48> 8d 7c 24 40 be 04 00 00 00 e8 38 ed 5f 00 8b 44 24 40 b9 01 00
RSP: 0018:ffffc90000007b80 EFLAGS: 00000056
RAX: 00000000ffffff01 RBX: ffffffff964879f8 RCX: ffffffff815e6939
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff964879f8
RBP: ffffc90000007c30 R08: ffffffff964879fb R09: 1ffffffff2c90f3f
R10: dffffc0000000000 R11: fffffbfff2c90f40 R12: 1ffff92000000f74
R13: ffffffff96487a00 R14: dffffc0000000000 R15: 1ffffffff2c90f40
FS:  00007fda3858b6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000005a39d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:117 [inline]
 _raw_spin_lock_irqsave+0xbc/0x100 kernel/locking/spinlock.c:162
 debug_object_deactivate+0x62/0x390 lib/debugobjects.c:749
 debug_hrtimer_deactivate kernel/time/hrtimer.c:415 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1653 [inline]
 __hrtimer_run_queues+0x2b9/0xb70 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:_compound_head include/linux/page-flags.h:196 [inline]
RIP: 0010:__SetPageLocked include/linux/page-flags.h:342 [inline]
RIP: 0010:shmem_alloc_and_acct_page+0x71a/0xbe0 mm/shmem.c:1613
Code: 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 cd 34 17 00 4d 8b 27 48 c7 c7 ff ff ff ff 4c 89 e6 e8 cb 19 d2 ff 42 80 3c 2b 00 <74> 08 4c 89 f7 e8 ac 34 17 00 48 89 5c 24 28 4d 8b 2e 45 89 ef 41
RSP: 0018:ffffc900035ef2e0 EFLAGS: 00000246
RAX: ffffffff81a72025 RBX: 1ffffd40002c5891 RCX: ffff88801f1d1dc0
RDX: 0000000000000002 RSI: 00fff00000000000 RDI: ffffffffffffffff
RBP: ffffc900035ef600 R08: ffffffff8d89f82f R09: 1ffffffff1b13f05
R10: dffffc0000000000 R11: fffffbfff1b13f06 R12: 00fff00000000000
R13: dffffc0000000000 R14: ffffea000162c488 R15: ffffea000162c480
 shmem_getpage_gfp+0x14f4/0x2d40 mm/shmem.c:1906
 shmem_fault+0x1ac/0x540 mm/shmem.c:2118
 __do_fault+0x141/0x330 mm/memory.c:3928
 do_read_fault mm/memory.c:4264 [inline]
 do_fault mm/memory.c:4392 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x2985/0x4410 mm/memory.c:4883
 faultin_page mm/gup.c:976 [inline]
 __get_user_pages+0x94b/0x11e0 mm/gup.c:1197
 populate_vma_page_range+0x213/0x290 mm/gup.c:1529
 __mm_populate+0x275/0x3b0 mm/gup.c:1638
 mm_populate include/linux/mm.h:2646 [inline]
 vm_mmap_pgoff+0x212/0x2d0 mm/util.c:556
 ksys_mmap_pgoff+0x140/0x790 mm/mmap.c:1635
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fda3a331e59
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:00007fda3858b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fda3a5aafa0 RCX: 00007fda3a331e59
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fda3a3c7d6f R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fda3a5ab038 R14: 00007fda3a5aafa0 R15: 00007fffecbffa98
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g17121 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=5501
rcu: rcu_preempt kthread starved for 10502 jiffies! g17121 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28016 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5741 Comm: syz.1.297 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:91 [inline]
RIP: 0010:lock_release+0x10c/0x8a0 kernel/locking/lockdep.c:5636
Code: 65 8b 05 f7 e3 a4 7e 85 c0 0f 85 aa 04 00 00 65 48 8b 1d 67 da a4 7e 4c 8d b3 ec 0a 00 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 47 05 00 00 41 83 3e 00 0f 85 7d 04 00 00 48 89 5c 24
RSP: 0018:ffffc90000007b80 EFLAGS: 00000803
RAX: 0000000000000000 RBX: ffff88801f1d1dc0 RCX: 6cba3c4776db6f00
RDX: 0000000000000000 RSI: ffffffff8a7a06e0 RDI: ffffffff8a7a06a0
RBP: ffffc90000007c90 R08: ffffffff8d89f82f R09: 1ffffffff1b13f05
R10: dffffc0000000000 R11: fffffbfff1b13f06 R12: 1ffff92000000f7c
R13: dffffc0000000000 R14: ffff88801f1d28ac R15: 1ffff92000000f94
FS:  00007fda3858b6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000005a39d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:158 [inline]
 _raw_spin_unlock_irqrestore+0x6d/0x120 kernel/locking/spinlock.c:194
 __run_hrtimer kernel/time/hrtimer.c:1681 [inline]
 __hrtimer_run_queues+0x3fd/0xb70 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:_compound_head include/linux/page-flags.h:196 [inline]
RIP: 0010:__SetPageLocked include/linux/page-flags.h:342 [inline]
RIP: 0010:shmem_alloc_and_acct_page+0x71a/0xbe0 mm/shmem.c:1613
Code: 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 cd 34 17 00 4d 8b 27 48 c7 c7 ff ff ff ff 4c 89 e6 e8 cb 19 d2 ff 42 80 3c 2b 00 <74> 08 4c 89 f7 e8 ac 34 17 00 48 89 5c 24 28 4d 8b 2e 45 89 ef 41
RSP: 0018:ffffc900035ef2e0 EFLAGS: 00000246
RAX: ffffffff81a72025 RBX: 1ffffd40002c5891 RCX: ffff88801f1d1dc0
RDX: 0000000000000002 RSI: 00fff00000000000 RDI: ffffffffffffffff
RBP: ffffc900035ef600 R08: ffffffff8d89f82f R09: 1ffffffff1b13f05
R10: dffffc0000000000 R11: fffffbfff1b13f06 R12: 00fff00000000000
R13: dffffc0000000000 R14: ffffea000162c488 R15: ffffea000162c480
 shmem_getpage_gfp+0x14f4/0x2d40 mm/shmem.c:1906
 shmem_fault+0x1ac/0x540 mm/shmem.c:2118
 __do_fault+0x141/0x330 mm/memory.c:3928
 do_read_fault mm/memory.c:4264 [inline]
 do_fault mm/memory.c:4392 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x2985/0x4410 mm/memory.c:4883
 faultin_page mm/gup.c:976 [inline]
 __get_user_pages+0x94b/0x11e0 mm/gup.c:1197
 populate_vma_page_range+0x213/0x290 mm/gup.c:1529
 __mm_populate+0x275/0x3b0 mm/gup.c:1638
 mm_populate include/linux/mm.h:2646 [inline]
 vm_mmap_pgoff+0x212/0x2d0 mm/util.c:556
 ksys_mmap_pgoff+0x140/0x790 mm/mmap.c:1635
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fda3a331e59
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:00007fda3858b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fda3a5aafa0 RCX: 00007fda3a331e59
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fda3a3c7d6f R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fda3a5ab038 R14: 00007fda3a5aafa0 R15: 00007fffecbffa98
 </TASK>