syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=531c/1/0x4000000000000000 softirq=107891/107900 fqs=10
rcu: 	(detected by 1, t=10502 jiffies, g=83445, q=552 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5821 Comm: syz-executor Not tainted 6.15.0-rc5-syzkaller-00136-g9c69f8884904 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
RIP: 0010:match_held_lock+0x0/0xc0 kernel/locking/lockdep.c:5303
Code: 00 ec a1 8d e8 41 fa 0d f6 90 0f 0b 90 90 e9 58 ff ff ff 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <53> 48 89 fb 48 39 77 10 74 55 66 83 7f 22 1f 76 65 48 8b 46 08 48
RSP: 0018:ffffc90000007df8 EFLAGS: 00000097
RAX: 000000000000000f RBX: ffff88802b000b68 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffff8880b8427858 RDI: ffff88802b000b68
RBP: ffff8880b8427858 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: ffffffff9ad83da0 R12: ffff88802b000000
R13: ffff88802b000af0 R14: 00000000ffffffff R15: 0000000000000003
FS:  00005555743c5500(0000) GS:ffff8881249e1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffff0000000 CR3: 000000005eb62000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __lock_is_held kernel/locking/lockdep.c:5599 [inline]
 lock_is_held_type+0xb0/0x150 kernel/locking/lockdep.c:5938
 lock_is_held include/linux/lockdep.h:249 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1727 [inline]
 __hrtimer_run_queues+0x86a/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:1038 [inline]
 __sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1055
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_is_held_type+0x107/0x150 kernel/locking/lockdep.c:5943
Code: 00 00 b8 ff ff ff ff 65 0f c1 05 6c 77 37 08 83 f8 01 75 2d 9c 58 f6 c4 02 75 43 48 f7 04 24 00 02 00 00 74 01 fb 48 83 c4 08 <44> 89 e8 5b 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc 45 31 ed eb
RSP: 0018:ffffc900046cf618 EFLAGS: 00000286
RAX: 0000000000000046 RBX: ffff88802b000b68 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8dbbc22f RDI: ffffffff8bf48320
RBP: ffffffff8e3bf5c0 R08: 0000000000000007 R09: 000000000007ffff
R10: 000000000000000b R11: 0000000000000000 R12: ffff88802b000000
R13: 0000000000000001 R14: 00000000ffffffff R15: 0000000000000003
 lookup_page_ext+0xe8/0x190 mm/page_ext.c:254
 page_ext_iter_begin include/linux/page_ext.h:132 [inline]
 page_table_check_set+0x3cc/0xb50 mm/page_table_check.c:113
 __page_table_check_ptes_set+0x318/0x420 mm/page_table_check.c:209
 page_table_check_ptes_set include/linux/page_table_check.h:74 [inline]
 set_ptes include/linux/pgtable.h:292 [inline]
 __copy_present_ptes mm/memory.c:961 [inline]
 copy_present_ptes mm/memory.c:1044 [inline]
 copy_pte_range mm/memory.c:1167 [inline]
 copy_pmd_range mm/memory.c:1255 [inline]
 copy_pud_range mm/memory.c:1292 [inline]
 copy_p4d_range mm/memory.c:1316 [inline]
 copy_page_range+0x1bd2/0x5fe0 mm/memory.c:1410
 dup_mmap kernel/fork.c:726 [inline]
 dup_mm kernel/fork.c:1734 [inline]
 copy_mm kernel/fork.c:1786 [inline]
 copy_process+0x862b/0x91a0 kernel/fork.c:2429
 kernel_clone+0xfc/0x960 kernel/fork.c:2844
 __do_sys_clone+0xce/0x120 kernel/fork.c:2987
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9214d851d3
Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffcda193a08 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9214d851d3
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 00005555743c57d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 0000000000070c74 R15: 00007ffcda193ba0
 </TASK>
rcu: rcu_preempt kthread starved for 10482 jiffies! g83445 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:27608 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 19352 Comm: syz.7.5688 Not tainted 6.15.0-rc5-syzkaller-00136-g9c69f8884904 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_many_cond+0x4aa/0x1290 kernel/smp.c:885
Code: 0c 00 85 ed 74 48 48 8b 44 24 20 49 89 c4 83 e0 07 49 c1 ec 03 48 89 c5 4d 01 f4 83 c5 03 e8 5d 17 0c 00 f3 90 41 0f b6 04 24 <40> 38 c5 7c 08 84 c0 0f 85 de 0b 00 00 8b 43 08 31 ff 83 e0 01 41
RSP: 0018:ffffc9000cc57460 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b8441720 RCX: ffffffff81af0bb9
RDX: ffff88802c85c880 RSI: ffffffff81af0b93 RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffed10170882e5
R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8880b853b040
FS:  0000000000000000(0000) GS:ffff888124ae1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffff0000000 CR3: 0000000031e70000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1275 [inline]
 flush_tlb_mm_range+0x322/0x1780 arch/x86/mm/tlb.c:1365
 tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:480 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:470 [inline]
 zap_pte_range mm/memory.c:1758 [inline]
 zap_pmd_range mm/memory.c:1823 [inline]
 zap_pud_range mm/memory.c:1852 [inline]
 zap_p4d_range mm/memory.c:1873 [inline]
 unmap_page_range+0x2035/0x4390 mm/memory.c:1894
 unmap_single_vma+0x194/0x2a0 mm/memory.c:1940
 unmap_vmas+0x22c/0x490 mm/memory.c:1984
 exit_mmap+0x1b9/0xb90 mm/mmap.c:1284
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 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:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa03278e56b
Code: Unable to access opcode bytes at 0x7fa03278e541.
RSP: 002b:00007fa033577f10 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: fffffffffffffffc RBX: 0000000000000005 RCX: 00007fa03278e56b
RDX: 00007fa033578fe0 RSI: 0000000080085502 RDI: 0000000000000005
RBP: 00007fa033578fe0 R08: 0000000000000000 R09: 00372e6364755f79
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000080085502
R13: 0000000800000000 R14: 0000200000000040 R15: 00007fa03281ba1e
 </TASK>