GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9740/1:b..l P9737/1:b..l rcu: (detected by 0, t=10505 jiffies, g=29269, q=375 ncpus=2) task:syz.2.1087 state:R running task stack:26888 pid:9737 tgid:9736 ppid:5871 task_flags:0x40044c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:58 [inline] RIP: 0010:stack_access_ok arch/x86/kernel/unwind_orc.c:393 [inline] RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline] RIP: 0010:unwind_next_frame+0xb4e/0x2390 arch/x86/kernel/unwind_orc.c:585 Code: 48 b8 00 00 00 00 00 fc ff df 48 8b 4c 24 20 0f b6 04 01 84 c0 0f 85 85 13 00 00 41 83 3e 00 0f 95 c0 49 39 df 0f 96 c1 20 c1 <49> 39 dc 0f 97 c0 20 c8 3c 01 75 18 48 8d 43 08 4c 39 f8 0f 97 c1 RSP: 0018:ffffc9000409f498 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffc9000409f5c0 RCX: 1ffff92000813e01 RDX: ffffffff90330012 RSI: 0000000000000002 RDI: ffffffff8be32620 RBP: 1ffff92000813eba R08: 0000000000000009 R09: ffffffff8172c195 R10: ffffc9000409f5c8 R11: fffff52000813ec5 R12: ffffc900040a0000 R13: 1ffff92000813ebb R14: ffffc9000409f5c8 R15: ffffc90004098000 __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 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4396 kmalloc_noprof include/linux/slab.h:905 [inline] slab_free_hook mm/slub.c:2369 [inline] slab_free mm/slub.c:4680 [inline] kmem_cache_free+0x166/0x400 mm/slub.c:4782 task_work_run+0x1d4/0x260 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x6b5/0x2300 kernel/exit.c:961 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 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:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4cdf38ebe9 RSP: 002b:00007f4ce01a5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: 0000000000000073 RBX: 00007f4cdf5b5fa0 RCX: 00007f4cdf38ebe9 RDX: 0000000000000088 RSI: 0000000000000002 RDI: 000000000000000a RBP: 00007f4cdf411e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4cdf5b6038 R14: 00007f4cdf5b5fa0 R15: 00007ffeccf32578 task:syz.0.1088 state:R running task stack:25096 pid:9740 tgid:9740 ppid:5862 task_flags:0x400040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:unwind_next_frame+0xb13/0x2390 arch/x86/include/asm/stacktrace.h:-1 Code: 78 4d 8b 7e 08 49 8d 5e 10 49 89 dd 49 c1 ed 03 48 b8 00 00 00 00 00 fc ff df 41 80 7c 05 00 00 74 08 48 89 df e8 4d 4a b0 00 <48> 89 9c 24 88 00 00 00 49 8d 5c 24 f8 4d 8b 66 10 48 b8 00 00 00 RSP: 0018:ffffc9000437eaf8 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffffc9000437ebd8 RCX: ffffffff8fbee9ac RDX: ffffffff903ec0f4 RSI: 0000000000000002 RDI: ffffffff8be32620 RBP: 1ffff9200086fd7a R08: 0000000000000011 R09: ffffffff8172c195 R10: ffffc9000437ec18 R11: ffffffff81ac3890 R12: ffffc9000437fef0 R13: 1ffff9200086fd7b R14: ffffc9000437ebc8 R15: ffffc90004378000 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548 __call_rcu_common kernel/rcu/tree.c:3123 [inline] call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3243 mas_wr_node_store lib/maple_tree.c:3893 [inline] mas_wr_store_entry+0x1f1b/0x25b0 lib/maple_tree.c:4104 mas_store_prealloc+0xb00/0xf60 lib/maple_tree.c:5510 vma_iter_store_new mm/vma.h:508 [inline] vma_complete+0x224/0xae0 mm/vma.c:354 __split_vma+0x8a6/0xa00 mm/vma.c:568 split_vma mm/vma.c:598 [inline] vma_modify+0x13b3/0x1970 mm/vma.c:1631 vma_modify_flags+0x1e8/0x230 mm/vma.c:1649 mprotect_fixup+0x407/0x9c0 mm/mprotect.c:819 do_mprotect_pkey+0x8cd/0xce0 mm/mprotect.c:993 __do_sys_mprotect mm/mprotect.c:1014 [inline] __se_sys_mprotect mm/mprotect.c:1011 [inline] __x64_sys_mprotect+0x80/0x90 mm/mprotect.c:1011 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: 0033:0x7f3d9898eca7 RSP: 002b:00007ffd7bc1f2e8 EFLAGS: 00000206 ORIG_RAX: 000000000000000a RAX: ffffffffffffffda RBX: 00007f3d997836c0 RCX: 00007f3d9898eca7 RDX: 0000000000000003 RSI: 0000000000020000 RDI: 00007f3d99764000 RBP: 0000000000000000 R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000021000 R11: 0000000000000206 R12: 00007ffd7bc1f440 R13: ffffffffffffffc0 R14: 0000000000001000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10505 jiffies! g29269 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:26632 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted 6.16.0-syzkaller-12084-g33caa208dba6 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: bat_events batadv_nc_worker RIP: 0010:do_raw_spin_unlock+0x0/0x240 kernel/locking/spinlock_debug.c:139 Code: 80 e1 07 80 c1 03 38 c1 0f 8c 6a ff ff ff e8 d7 13 85 00 e9 60 ff ff ff 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <66> 0f 1f 00 55 41 57 41 56 41 55 41 54 53 48 89 fb 49 bc 00 00 00 RSP: 0000:ffffc90000a08c78 EFLAGS: 00000086 RAX: 0d4f87390f620600 RBX: 0000000000000802 RCX: 0d4f87390f620600 RDX: 0000000000000003 RSI: ffffffff8dba39a7 RDI: ffffffff99d808a0 RBP: ffffc90000a08d08 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000141170 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff99d808a0 R15: 1ffff92000141190 FS: 0000000000000000(0000) GS:ffff888125d21000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c36e252 CR3: 000000007a1bc000 CR4: 00000000003526f0 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_unlock_irqrestore+0x78/0x110 kernel/locking/spinlock.c:194 debug_hrtimer_deactivate kernel/time/hrtimer.c:450 [inline] debug_deactivate+0x1d/0x200 kernel/time/hrtimer.c:490 __run_hrtimer kernel/time/hrtimer.c:1729 [inline] __hrtimer_run_queues+0x2b0/0xc60 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+0x108/0x410 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 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:check_preemption_disabled+0x17/0x120 lib/smp_processor_id.c:14 Code: 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 53 48 83 ec 10 65 48 8b 05 be 1e 27 07 48 89 44 24 08 <65> 8b 05 c6 1e 27 07 65 8b 0d bb 1e 27 07 f7 c1 ff ff ff 7f 74 23 RSP: 0000:ffffc90000117878 EFLAGS: 00000286 RAX: 0d4f87390f620600 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8be32660 RDI: ffffffff8be32620 RBP: ffffffff8b46b097 R08: 0000000000000001 R09: 0000000000000000 R10: dffffc0000000000 R11: fffffbfff1f468c7 R12: 0000000000000000 R13: ffff888077d60b98 R14: 0000000000000000 R15: 0000000000000001 rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:751 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x5f/0x360 kernel/locking/lockdep.c:5831 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] batadv_nc_purge_paths+0xe7/0x3b0 net/batman-adv/network-coding.c:442 batadv_nc_worker+0x369/0x610 net/batman-adv/network-coding.c:722 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245