syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=8a24/1/0x4000000000000000 softirq=101107/101112 fqs=2
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P21120/1:b..l
rcu: 	(detected by 1, t=10506 jiffies, g=92893, q=168 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 21153 Comm: syz.5.3883 Not tainted 6.14.0-rc7-syzkaller-00205-g586de92313fc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:__sanitizer_cov_trace_pc+0x66/0x70 kernel/kcov.c:235
Code: 82 08 16 00 00 83 f8 02 75 20 48 8b 8a 10 16 00 00 8b 92 0c 16 00 00 48 8b 01 48 83 c0 01 48 39 d0 73 07 48 89 01 48 89 34 c1 <c3> cc cc cc cc 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000007e28 EFLAGS: 00000046
RAX: 0000000080010001 RBX: 1bc16d674ec85a0e RCX: ffffffff81a720c5
RDX: ffff888026df0000 RSI: ffffffff81a720d3 RDI: 0000000000000006
RBP: 1839e023a8000000 R08: 0000000000000006 R09: 1839e023a8000000
R10: 1bc16d674ec85a0e R11: 0000000000000002 R12: ffff8880858ed340
R13: ffff8880b862c780 R14: ffff8880b862c680 R15: ffffffff896ae430
FS:  00007f2b3926b6c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2b3926af98 CR3: 0000000069274000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 __run_hrtimer kernel/time/hrtimer.c:1767 [inline]
 __hrtimer_run_queues+0x423/0xae0 kernel/time/hrtimer.c:1865
 hrtimer_interrupt+0x392/0x8e0 kernel/time/hrtimer.c:1927
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x10f/0x400 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:obj_cgroup_charge+0x0/0x4d0 mm/memcontrol.c:2900
Code: eb b0 48 89 ef e8 00 70 f7 ff eb 86 48 89 ef e8 f6 6f f7 ff e9 45 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <66> 0f 1f 00 41 57 41 56 41 89 f6 41 55 49 89 fd 41 54 55 48 89 d5
RSP: 0018:ffffc900030b7b30 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffff88814040d8c0 RCX: 0000000000000000
RDX: 00000000000001c8 RSI: 0000000000000dc0 RDI: ffff888029136c00
RBP: ffffc900030b7bd0 R08: ffffc900030b7bd0 R09: 0000000000000000
R10: ffff88801208cfc0 R11: 0000000000000001 R12: 0000000000000000
R13: ffff888029136c00 R14: 0000000000000000 R15: 0000000000000001
 __memcg_slab_post_alloc_hook+0x1b6/0x9b0 mm/memcontrol.c:2997
 memcg_slab_post_alloc_hook mm/slub.c:2152 [inline]
 slab_post_alloc_hook mm/slub.c:4125 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 kmem_cache_alloc_noprof+0x366/0x3d0 mm/slub.c:4171
 alloc_vfsmnt+0x23/0x6f0 fs/namespace.c:341
 clone_mnt+0x6d/0xf90 fs/namespace.c:1332
 copy_tree+0x39e/0x9c0 fs/namespace.c:2209
 copy_mnt_ns+0x1b5/0xa70 fs/namespace.c:3998
 create_new_namespaces+0xd3/0xad0 kernel/nsproxy.c:78
 unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:228
 ksys_unshare+0x45d/0xa40 kernel/fork.c:3342
 __do_sys_unshare kernel/fork.c:3413 [inline]
 __se_sys_unshare kernel/fork.c:3411 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3411
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2b3838d169
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:00007f2b3926b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f2b385a5fa0 RCX: 00007f2b3838d169
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040020000
RBP: 00007f2b3840e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f2b385a5fa0 R15: 00007ffcdd606c78
 </TASK>
task:syz.0.3870      state:R  running task     stack:27832 pid:21120 tgid:21113 ppid:17329  task_flags:0x40044c flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0xf43/0x5890 kernel/sched/core.c:6765
 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6944
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 zap_pte_range mm/memory.c:1771 [inline]
 zap_pmd_range mm/memory.c:1833 [inline]
 zap_pud_range mm/memory.c:1862 [inline]
 zap_p4d_range mm/memory.c:1883 [inline]
 unmap_page_range+0xee3/0x4390 mm/memory.c:1904
 unmap_single_vma+0x194/0x2b0 mm/memory.c:1950
 unmap_vmas+0x22f/0x490 mm/memory.c:1994
 exit_mmap+0x1c1/0xba0 mm/mmap.c:1284
 __mmput+0x12a/0x410 kernel/fork.c:1356
 mmput+0x62/0x70 kernel/fork.c:1378
 exit_mm kernel/exit.c:570 [inline]
 do_exit+0x9ba/0x2db0 kernel/exit.c:925
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087
 get_signal+0x24ed/0x26c0 kernel/signal.c:3036
 arch_do_signal_or_restart+0x90/0x7e0 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/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbb0ff8d169
RSP: 002b:00007fbb10ea4038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: 0000000000010106 RBX: 00007fbb101a6080 RCX: 00007fbb0ff8d169
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 000000000000000a
RBP: 00007fbb1000e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fbb101a6080 R15: 00007ffd0b3fefa8
 </TASK>
rcu: rcu_preempt kthread starved for 10450 jiffies! g92893 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:27552 pid:18    tgid:18    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0xf43/0x5890 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6857
 schedule_timeout+0x124/0x280 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2024
 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2226
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 16407 Comm: kworker/u8:26 Not tainted 6.14.0-rc7-syzkaller-00205-g586de92313fc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_many_cond+0x4c6/0x12c0 kernel/smp.c:885
Code: 0c 00 85 ed 74 4d 48 b8 00 00 00 00 00 fc ff df 4d 89 fc 4c 89 fd 49 c1 ec 03 83 e5 07 49 01 c4 83 c5 03 e8 ac 0e 0c 00 f3 90 <41> 0f b6 04 24 40 38 c5 7c 08 84 c0 0f 85 e8 0b 00 00 8b 43 08 31
RSP: 0018:ffffc9000c26f928 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b8646a00 RCX: ffffffff81ade1ea
RDX: ffff8880302da440 RSI: ffffffff81ade1c4 RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000006 R12: ffffed10170c8d41
R13: 0000000000000001 R14: ffff8880b873fe80 R15: ffff8880b8646a08
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fde58960426 CR3: 000000000df80000 CR4: 00000000003526f0
DR0: 0000000100000000 DR1: 0000000000000040 DR2: 0000000000000003
DR3: 0000000000000009 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:2118 [inline]
 text_poke_bp_batch+0x22b/0x760 arch/x86/kernel/alternative.c:2328
 text_poke_flush arch/x86/kernel/alternative.c:2519 [inline]
 text_poke_flush arch/x86/kernel/alternative.c:2516 [inline]
 text_poke_finish+0x30/0x40 arch/x86/kernel/alternative.c:2526
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 jump_label_update+0x1d7/0x400 kernel/jump_label.c:920
 static_key_disable_cpuslocked+0x158/0x1c0 kernel/jump_label.c:240
 static_key_disable+0x1a/0x20 kernel/jump_label.c:248
 toggle_allocation_gate mm/kfence/core.c:855 [inline]
 toggle_allocation_gate+0x147/0x260 mm/kfence/core.c:842
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>