syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=2bec/1/0x4000000000000000 softirq=67299/67299 fqs=0
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9847/1:b..l P12243/1:b..l P11939/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=47345, q=348 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 12248 Comm: syz.3.1557 Not tainted 6.16.0-rc4-syzkaller-00013-g66701750d556 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:473 [inline]
RIP: 0010:lock_release+0x287/0x3e0 kernel/locking/lockdep.c:5894
Code: 89 f6 48 8b 54 24 18 e8 57 30 00 00 48 8b 5c 24 08 48 c7 c7 30 ee b6 8d e8 d6 dd c8 09 b8 ff ff ff ff 65 0f c1 05 e9 0a ff 10 <83> f8 01 75 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24
RSP: 0018:ffffc90000007c08 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 0000000000000002 RCX: ecce87fd6fed8000
RDX: 0000000000000001 RSI: ffffffff8db6ee30 RDI: ffffffff8be28cc0
RBP: ffff88802c1a8b18 R08: ffff888079adf15f R09: 1ffff1100f35be2b
R10: dffffc0000000000 R11: ffffed100f35be2c R12: 0000000000000001
R13: 0000000000000001 R14: ffffffff8e13ee20 R15: ffff88802c1a8000
FS:  0000555567ad1500(0000) GS:ffff888125c50000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2fc12ff8 CR3: 0000000033301000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock include/linux/rcupdate.h:871 [inline]
 advance_sched+0xb23/0xc90 net/sched/sch_taprio.c:987
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 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:debug_smp_processor_id+0x0/0x20 lib/smp_processor_id.c:59
Code: c7 20 a9 1f 8e 4c 89 f6 e8 4d 18 90 f9 e9 66 ff ff ff cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 48 c7 c7 60 8c e2 8b 48 c7 c6 a0 8c e2 8b eb 1c 66 66
RSP: 0018:ffffc90003fafc28 EFLAGS: 00000287
RAX: 0000000000000000 RBX: ffffffff822c4ded RCX: dffffc0000000000
RDX: 0000000000000001 RSI: ffffffff8be28ca0 RDI: ffffffff8be28c60
RBP: 0000000000000028 R08: 0000000000000000 R09: ffff8881404de800
R10: dffffc0000000000 R11: ffffed102809b131 R12: ffff88802c1a8000
R13: dffffc0000000000 R14: 0000000000000006 R15: ffff8880b863b400
 refill_stock+0x4a9/0x870 mm/memcontrol.c:1952
 obj_cgroup_uncharge_pages mm/memcontrol.c:2782 [inline]
 refill_obj_stock+0x4fd/0x850 mm/memcontrol.c:3065
 __memcg_slab_free_hook+0x127/0x3d0 mm/memcontrol.c:3219
 memcg_slab_free_hook mm/slub.c:2206 [inline]
 slab_free mm/slub.c:4640 [inline]
 kmem_cache_free+0x223/0x400 mm/slub.c:4745
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:114
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f79cb98e929
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:00007fffef52a618 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00000000000ae861 RCX: 00007f79cb98e929
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f79cbbb7ba0 R08: 0000000000000001 R09: 0000001eef52a90f
R10: 00007f79cb800000 R11: 0000000000000246 R12: 00007f79cbbb5fac
R13: 00007f79cbbb5fa0 R14: ffffffffffffffff R15: 00007fffef52a730
 </TASK>
task:kworker/u8:14   state:R  running task     stack:24568 pid:11939 tgid:11939 ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7108
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:srso_alias_safe_ret+0x5/0x7 arch/x86/lib/retpoline.S:175
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 48 8d 64 24 08 <c3> cc e8 f4 ff ff ff 0f 0b cc cc cc cc cc cc cc cc cc cc cc cc cc
RSP: 0018:ffffc90003d6f358 EFLAGS: 00000282
RAX: ffffffff818c9240 RBX: ffffc90003d6f420 RCX: 08623387517b1400
RDX: 0000000000000001 RSI: ffffffff818c9240 RDI: ffffc90003d6f420
RBP: ffffc90003d6f3f0 R08: ffffc90003d6fc70 R09: ffffc90003d6f3b8
R10: dffffc0000000000 R11: ffffffff81ace6d0 R12: ffff888071620000
R13: ffff888054b80800 R14: ffffffff81ace6d0 R15: ffffc90003d6f368
 __pfx_stack_trace_consume_entry+0x10/0x10 kernel/stacktrace.c:-1
 arch_stack_walk+0x110/0x150 arch/x86/kernel/stacktrace.c:27
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4359
 kmalloc_noprof include/linux/slab.h:905 [inline]
 batadv_forw_packet_alloc+0x1e9/0x390 net/batman-adv/send.c:521
 batadv_iv_ogm_aggregate_new net/batman-adv/bat_iv_ogm.c:571 [inline]
 batadv_iv_ogm_queue_add+0x85f/0xd30 net/batman-adv/bat_iv_ogm.c:678
 batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:857 [inline]
 batadv_iv_ogm_schedule+0xabd/0xea0 net/batman-adv/bat_iv_ogm.c:876
 batadv_iv_send_outstanding_bat_ogm_packet+0x6c6/0x7e0 net/batman-adv/bat_iv_ogm.c:1720
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
task:syz.8.1553      state:R  running task     stack:25848 pid:12243 tgid:12238 ppid:9881   task_flags:0x40054c flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7108
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5875
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 0b dd fe 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90003f1f078 EFLAGS: 00000206
RAX: 251da5d1dcfaae00 RBX: 0000000000000000 RCX: 251da5d1dcfaae00
RDX: 0000000000000000 RSI: ffffffff8db6ee30 RDI: ffffffff8be28cc0
RBP: ffffffff81728af5 R08: 0000000000000000 R09: ffffffff81728af5
R10: dffffc0000000000 R11: fffff520007e3e55 R12: 0000000000000002
R13: ffffffff8e13ee20 R14: 0000000000000000 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:758
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kmem_cache_free+0x18f/0x400 mm/slub.c:4745
 anon_vma_chain_free mm/rmap.c:147 [inline]
 unlink_anon_vmas+0x614/0x670 mm/rmap.c:447
 free_pgtables+0x7bf/0xaf0 mm/memory.c:402
 exit_mmap+0x444/0xb50 mm/mmap.c:1295
 __mmput+0x118/0x420 kernel/fork.c:1121
 exit_mm+0x1da/0x2c0 kernel/exit.c:581
 do_exit+0x648/0x22e0 kernel/exit.c:952
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1105
 get_signal+0x1286/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:111
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff282d8e929
RSP: 002b:00007ff283c7c0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007ff282fb6088 RCX: 00007ff282d8e929
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff282fb6088
RBP: 00007ff282fb6080 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff282fb608c
R13: 0000000000000000 R14: 00007ffccece7f70 R15: 00007ffccece8058
 </TASK>
task:syz-executor    state:R  running task     stack:21784 pid:9847  tgid:9847  ppid:9832   task_flags:0x400140 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6965
 preempt_schedule+0xae/0xc0 kernel/sched/core.c:6989
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 copy_pte_range mm/memory.c:1206 [inline]
 copy_pmd_range+0x6727/0x7000 mm/memory.c:1267
 copy_pud_range mm/memory.c:1304 [inline]
 copy_p4d_range mm/memory.c:1328 [inline]
 copy_page_range+0xc46/0x1270 mm/memory.c:1416
 dup_mmap+0xf57/0x1ac0 mm/mmap.c:1838
 dup_mm kernel/fork.c:1477 [inline]
 copy_mm+0x13c/0x4b0 kernel/fork.c:1529
 copy_process+0x1706/0x3c00 kernel/fork.c:2169
 kernel_clone+0x21e/0x870 kernel/fork.c:2599
 __do_sys_clone kernel/fork.c:2742 [inline]
 __se_sys_clone kernel/fork.c:2726 [inline]
 __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2726
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe74f185193
RSP: 002b:00007ffeb0cf9de8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe74f185193
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 0000555583fa07d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 00000000000ae85c R15: 00007ffeb0cf9f80
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g47345 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=42153
rcu: rcu_preempt kthread starved for 10502 jiffies! g47345 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:26632 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>