rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=dfd/1/0x4000000000000000 softirq=39992/39996 fqs=63 
	(detected by 0, t=10502 jiffies, g=54205, q=593)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 14434 Comm: syz.5.2170 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:35 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline]
RIP: 0010:lock_acquire+0x14a/0x3f0 kernel/locking/lockdep.c:5619
Code: 0f b6 04 38 84 c0 0f 85 f2 01 00 00 41 83 3e 00 0f 85 00 01 00 00 48 c7 84 24 a0 00 00 00 00 00 00 00 9c 8f 84 24 a0 00 00 00 <4c> 8b b4 24 a0 00 00 00 fa 48 c7 c7 c0 23 0b 8a e8 c1 47 4c 08 65
RSP: 0018:ffffc90000dd0b40 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 22964ab2f98a5b00
RDX: 0000000000000000 RSI: ffffffff8a599320 RDI: ffffffff8a5992e0
RBP: ffffc90000dd0c58 R08: dffffc0000000000 R09: fffffbfff1ad2dd6
R10: fffffbfff1ad2dd6 R11: 1ffffffff1ad2dd5 R12: ffff888077a55b00
R13: 1ffff920001ba174 R14: ffff8880260f466c R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4d94f94e9c CR3: 000000000be8e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:363 [inline]
 advance_sched+0x47/0x940 net/sched/sch_taprio.c:716
 __run_hrtimer kernel/time/hrtimer.c:1690 [inline]
 __hrtimer_run_queues+0x53d/0xc40 kernel/time/hrtimer.c:1754
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
 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:__sanitizer_cov_trace_const_cmp8+0x7a/0x80 kernel/kcov.c:302
Code: c1 e0 05 4d 8d 50 28 4d 39 ca 77 1e 4a c7 44 02 08 07 00 00 00 4a 89 7c 02 10 4a 89 74 02 18 4a 89 44 02 20 48 ff c1 48 89 0a <c3> 0f 1f 44 00 00 48 8b 4e 08 48 83 c1 f8 48 c1 c1 3d 48 83 f9 07
RSP: 0018:ffffc9000325f4a8 EFLAGS: 00000293
RAX: ffffffff81b49c84 RBX: ffffea0001db54c8 RCX: ffff8880260f3b80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffff940003b6a91
R10: fffff940003b6a91 R11: 1ffffd40003b6a90 R12: 0000000000000000
R13: 00fff00000000000 R14: 1ffffd40003b6a99 R15: ffffea0001db54c0
 _compound_head include/linux/page-flags.h:198 [inline]
 PageSwapBacked include/linux/page-flags.h:371 [inline]
 PageSwapCache include/linux/page-flags.h:415 [inline]
 free_swap_cache+0x104/0x2e0 mm/swap_state.c:291
 free_pages_and_swap_cache+0x5c/0x90 mm/swap_state.c:319
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu+0xc5/0x170 mm/mmu_gather.c:247
 zap_pte_range mm/memory.c:1456 [inline]
 zap_pmd_range mm/memory.c:1505 [inline]
 zap_pud_range mm/memory.c:1534 [inline]
 zap_p4d_range mm/memory.c:1555 [inline]
 unmap_page_range+0x2096/0x2520 mm/memory.c:1576
 unmap_vmas+0x11b/0x230 mm/memory.c:1653
 exit_mmap+0x38f/0x5f0 mm/mmap.c:3212
 __mmput+0x115/0x3b0 kernel/fork.c:1127
 exit_mm+0x567/0x6c0 kernel/exit.c:550
 do_exit+0x5a1/0x20a0 kernel/exit.c:870
 do_group_exit+0x12e/0x300 kernel/exit.c:997
 get_signal+0x6ca/0x12c0 kernel/signal.c:2900
 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fed4673db69
Code: Unable to access opcode bytes at RIP 0x7fed4673db3f.
RSP: 002b:00007fed445a50e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fed46964fa8 RCX: 00007fed4673db69
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fed46964fa8
RBP: 00007fed46964fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fed46964fac
R13: 0000000000000000 R14: 00007ffea976d460 R15: 00007ffea976d548
 </TASK>
rcu: rcu_preempt kthread starved for 10354 jiffies! g54205 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:27848 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1e0 kernel/sched/core.c:6459
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x98/0x350 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:
NMI backtrace for cpu 0
CPU: 0 PID: 14486 Comm: syz.6.2187 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:1818
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1690 [inline]
 __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
 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:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_many_cond+0xb88/0xd70 kernel/smp.c:969
Code: b6 44 05 00 84 c0 0f 85 9d 00 00 00 41 8b 1c 24 89 de 83 e6 01 31 ff e8 a6 46 0b 00 83 e3 01 75 07 e8 3c 43 0b 00 eb 43 f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 44 05 00 84 c0 75 11 41 f7
RSP: 0018:ffffc9000355f1c0 EFLAGS: 00000246
RAX: ffffffff816c810b RBX: 0000000000000001 RCX: 0000000000080000
RDX: ffffc9000d901000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000355f300 R08: dffffc0000000000 R09: fffffbfff1ff6e4c
R10: fffffbfff1ff6e4c R11: 1ffffffff1ff6e4b R12: ffff8880b9140588
R13: 1ffff110172280b1 R14: ffff8880b903b380 R15: 0000000000000001
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135
 kill_bdev block/bdev.c:76 [inline]
 set_blocksize+0x2eb/0x370 block/bdev.c:157
 sb_set_blocksize+0x45/0xe0 block/bdev.c:166
 ocfs2_get_sector+0x9b/0x4a0 fs/ocfs2/super.c:1757
 ocfs2_sb_probe fs/ocfs2/super.c:748 [inline]
 ocfs2_fill_super+0x3cd/0x4d80 fs/ocfs2/super.c:989
 mount_bdev+0x287/0x3c0 fs/super.c:1400
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x24a/0xa40 fs/namespace.c:3014
 do_mount fs/namespace.c:3357 [inline]
 __do_sys_mount fs/namespace.c:3565 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3542
 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: 0033:0x7f4cebcaa30a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007f4ce9b0fe68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f4ce9b0fef0 RCX: 00007f4cebcaa30a
RDX: 0000200000004440 RSI: 0000200000000040 RDI: 00007f4ce9b0feb0
RBP: 0000200000004440 R08: 00007f4ce9b0fef0 R09: 00000000020008c0
R10: 00000000020008c0 R11: 0000000000000246 R12: 0000200000000040
R13: 00007f4ce9b0feb0 R14: 0000000000004463 R15: 0000200000000180
 </TASK>