syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (2 GPs behind) idle=6244/1/0x4000000000000000 softirq=16977/16985 fqs=4
rcu: 	(detected by 0, t=10502 jiffies, g=16145, q=710 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5780 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:rb_add_linked include/linux/rbtree.h:282 [inline]
RIP: 0010:timerqueue_linked_add+0x266/0x2e0 lib/timerqueue.c:96
Code: 5c 8c f6 4c 89 f8 48 c1 e8 03 80 3c 28 00 74 08 4c 89 ff e8 7c 5a 8c f6 4d 89 2f 4c 89 ef 48 89 de e8 3e 5f ff ff 4d 8d 7d 18 <4d> 89 fe 49 c1 ee 03 41 80 3c 2e 00 74 08 4c 89 ff e8 64 59 8c f6
RSP: 0018:ffffc90000a08d58 EFLAGS: 00000092
RAX: 1ffff1100f366e60 RBX: ffff8880b8728418 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8880b8728418 RDI: ffff888079b37300
RBP: dffffc0000000000 R08: ffff888079b37317 R09: 0000000000000000
R10: ffff888079b37308 R11: ffffed100f366e63 R12: 1ffff110170e5078
R13: ffff888079b37300 R14: 0000000000000000 R15: ffff888079b37318
FS:  00005555752bc500(0000) GS:ffff88812538a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feff0a72780 CR3: 000000007e2ec000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 enqueue_hrtimer+0x18e/0x2c0 kernel/time/hrtimer.c:1117
 __run_hrtimer kernel/time/hrtimer.c:1946 [inline]
 __hrtimer_run_queues+0x4d2/0xa20 kernel/time/hrtimer.c:1994
 hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_done arch/x86/include/asm/unwind.h:50 [inline]
RIP: 0010:unwind_get_return_address+0x16/0x90 arch/x86/kernel/unwind_orc.c:382
Code: e3 31 0a 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 53 48 89 fb 49 be 00 00 00 00 00 fc ff df <48> 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 4c 83 3b 00 74 3a 48
RSP: 0018:ffffc90004077528 EFLAGS: 00000202
RAX: 000000009145c701 RBX: ffffc90004077548 RCX: 0000000000000046
RDX: 0000000000000001 RSI: ffffffff8e21a1b7 RDI: ffffc90004077548
RBP: ffffc900040775d0 R08: ffffc90004077c40 R09: 0000000000000000
R10: ffffc90004077598 R11: fffff5200080eeb5 R12: ffff88807dbd9ec0
R13: 00000000ffffffff R14: dffffc0000000000 R15: ffffc90004077548
 arch_stack_walk+0xfb/0x150 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5295 [inline]
 __kmalloc_node_track_caller_noprof+0x4db/0x7b0 mm/slub.c:5407
 __kmemdup_nul mm/util.c:64 [inline]
 kstrdup+0x42/0x100 mm/util.c:84
 binderfs_binder_device_create+0x2cf/0x940 drivers/android/binderfs.c:165
 binderfs_fill_super+0x9ed/0xfc0 drivers/android/binderfs.c:679
 vfs_get_super fs/super.c:1327 [inline]
 get_tree_nodev+0xbb/0x150 fs/super.c:1346
 vfs_get_tree+0x92/0x2a0 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]
 do_new_mount_fc fs/namespace.c:3758 [inline]
 do_new_mount+0x341/0xd30 fs/namespace.c:3834
 do_mount fs/namespace.c:4167 [inline]
 __do_sys_mount fs/namespace.c:4383 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4360
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f10f339e0ca
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd37d48f08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f10f343279e RCX: 00007f10f339e0ca
RDX: 00007f10f3443244 RSI: 00007f10f343279e RDI: 00007f10f3443244
RBP: 00007f10f34329e7 R08: 0000000000000000 R09: 00007ffd37d48fa0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f10f34074b0
R13: 00007f10f3407488 R14: 00007ffd37d49188 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10494 jiffies! g16145 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:27968 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5388 [inline]
 __schedule+0x1821/0x5740 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7283
 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
 kthread+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 48 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:check_kcov_mode kernel/kcov.c:194 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x36/0x70 kernel/kcov.c:217
Code: 98 9b 73 11 65 8b 15 b9 9b 73 11 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 d4 16 00 00 00 74 2c 8b 91 b0 16 00 00 <83> fa 02 75 21 48 8b 91 b8 16 00 00 48 8b 32 48 8d 7e 01 8b 89 b4
RSP: 0018:ffffc90000b876f8 EFLAGS: 00000246
RAX: ffffffff81b9c256 RBX: ffff8880b863c148 RCX: ffff888022ed8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000b87840 R08: ffffffff9030bcf7 R09: 1ffffffff206179e
R10: dffffc0000000000 R11: fffffbfff206179f R12: 1ffff110170e8169
R13: dffffc0000000000 R14: ffff8880b8740b48 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff88812528a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6364365440 CR3: 000000000e74a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 csd_lock_wait kernel/smp.c:342 [inline]
 smp_call_function_many_cond+0xfe6/0x13d0 kernel/smp.c:892
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057
 on_each_cpu include/linux/smp.h:72 [inline]
 smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline]
 smp_text_poke_batch_finish+0x5f5/0x1160 arch/x86/kernel/alternative.c:2983
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x128/0x240 kernel/jump_label.c:210
 static_key_enable+0x1a/0x20 kernel/jump_label.c:223
 toggle_allocation_gate+0xab/0x290 mm/kfence/core.c:906
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
 kthread+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>