rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P15861/1:b..l P15859/1:b..l P6360/1:b..l P5220/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=62733, q=235 ncpus=2)
task:udevd state:R running task stack:24696 pid:5220 tgid:5220 ppid:1 task_flags:0x400140 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6961
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288
irqentry_exit+0x36/0x90 kernel/entry/common.c:197
asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709
RIP: 0010:__read_once_word_nocheck+0x3/0x10 include/asm-generic/rwonce.h:68
Code: e8 42 c5 ac 03 e9 c8 fa ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 8b 07 c8 85 2c 0a 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000448f470 EFLAGS: 00000202
RAX: 00007f9c763153a7 RBX: 0000000000000001 RCX: ffffc90004490000
RDX: ffffc90004490001 RSI: ffffc9000448ff58 RDI: ffffc9000448ffd8
RBP: ffffc9000448f530 R08: ffffffff913acea2 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffffc9000448f538
R13: ffffc9000448f4e8 R14: ffffc9000448ff58 R15: 0000000000000001
deref_stack_regs arch/x86/kernel/unwind_orc.c:421 [inline]
unwind_next_frame+0xe57/0x20a0 arch/x86/kernel/unwind_orc.c:596
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:330 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:356
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4191 [inline]
slab_alloc_node mm/slub.c:4240 [inline]
kmem_cache_alloc_lru_noprof+0x1d0/0x3b0 mm/slub.c:4259
__d_alloc+0x32/0xae0 fs/dcache.c:1690
d_alloc_parallel+0x111/0x1480 fs/dcache.c:2549
__lookup_slow+0x193/0x460 fs/namei.c:1793
lookup_slow fs/namei.c:1825 [inline]
walk_component+0x353/0x5b0 fs/namei.c:2129
lookup_last fs/namei.c:2630 [inline]
path_lookupat+0x142/0x6d0 fs/namei.c:2654
filename_lookup+0x224/0x5f0 fs/namei.c:2683
do_readlinkat+0xce/0x3a0 fs/stat.c:576
__do_sys_readlink fs/stat.c:613 [inline]
__se_sys_readlink fs/stat.c:610 [inline]
__x64_sys_readlink+0x78/0xc0 fs/stat.c:610
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9c763153a7
RSP: 002b:00007fffea42bb98 EFLAGS: 00000246 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007fffea42c070 RCX: 00007f9c763153a7
RDX: 0000000000000400 RSI: 00007fffea42bba0 RDI: 00007fffea42c070
RBP: 00007fffea42bba0 R08: 00005632ff3c8700 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000400
R13: 0000000000000100 R14: 00005632df6adbe0 R15: 00007fffea42caf0
task:kworker/u8:9 state:R running task stack:23576 pid:6360 tgid:6360 ppid:2 task_flags:0x4208160 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6961
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288
irqentry_exit+0x36/0x90 kernel/entry/common.c:197
asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709
RIP: 0010:lock_release+0x183/0x2f0 kernel/locking/lockdep.c:5893
Code: 0f c1 05 f8 3d 3f 12 83 f8 01 0f 85 1d 01 00 00 9c 58 f6 c4 02 0f 85 08 01 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 0d fc 3e 12 0f 85 58 01 00 00 48 83 c4 18 5b 41 5c 41
RSP: 0018:ffffc9000c417ae0 EFLAGS: 00000206
RAX: d4fd3a9c23db5100 RBX: ffffffff8e5c15a0 RCX: ffffc9000c417aec
RDX: 0000000000000002 RSI: ffffffff8de2d660 RDI: ffffffff8c163000
RBP: 000000000000005d R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8b617c55
R13: 0000000000000202 R14: ffff888030b1c880 R15: 0000000000000003
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock include/linux/rcupdate.h:871 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
batadv_nc_worker+0x89a/0x1030 net/batman-adv/network-coding.c:719
process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236
process_scheduled_works kernel/workqueue.c:3319 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
kthread+0x3c2/0x780 kernel/kthread.c:463
ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
task:syz.0.1802 state:R running task stack:26776 pid:15859 tgid:15849 ppid:5853 task_flags:0x400140 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6961
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288
irqentry_exit+0x36/0x90 kernel/entry/common.c:197
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x627/0x20a0 arch/x86/kernel/unwind_orc.c:517
Code: c1 ea 03 80 3c 02 00 0f 85 0c 17 00 00 48 89 c8 4d 8b 7d 38 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 0f b6 34 10 48 8d 41 01 <48> 89 c7 48 c1 ef 03 0f b6 14 17 48 89 cf 83 e7 07 40 38 fe 40 0f
RSP: 0018:ffffc90003bdf268 EFLAGS: 00000a02
RAX: ffffffff9142efbb RBX: 0000000000000001 RCX: ffffffff9142efba
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff90bdc3d0
RBP: ffffc90003bdf320 R08: ffffffff9142efbe R09: 0000000000000000
R10: 0000000000000004 R11: 00000000000085d6 R12: ffffc90003bdf328
R13: ffffc90003bdf2d8 R14: 0000000000000005 R15: ffffc90003bdfe28
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:330 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:356
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4191 [inline]
slab_alloc_node mm/slub.c:4240 [inline]
kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4247
__kernfs_new_node+0xd2/0x8e0 fs/kernfs/dir.c:637
kernfs_new_node+0x13c/0x1e0 fs/kernfs/dir.c:713
__kernfs_create_file+0x53/0x350 fs/kernfs/file.c:1039
sysfs_add_file_mode_ns+0x207/0x3c0 fs/sysfs/file.c:319
create_files fs/sysfs/group.c:76 [inline]
internal_create_group+0x578/0xf30 fs/sysfs/group.c:183
internal_create_groups+0x9d/0x150 fs/sysfs/group.c:223
setup_gid_attrs drivers/infiniband/core/sysfs.c:1162 [inline]
ib_setup_port_attrs+0x41f/0x600 drivers/infiniband/core/sysfs.c:1439
add_one_compat_dev+0x558/0x7d0 drivers/infiniband/core/device.c:1005
rdma_dev_init_net+0x2b1/0x530 drivers/infiniband/core/device.c:1221
ops_init+0x1df/0x5f0 net/core/net_namespace.c:136
setup_net+0x10f/0x380 net/core/net_namespace.c:438
copy_net_ns+0x2a6/0x5f0 net/core/net_namespace.c:570
create_new_namespaces+0x3ea/0xa90 kernel/nsproxy.c:110
unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:218
ksys_unshare+0x45b/0xa40 kernel/fork.c:3127
__do_sys_unshare kernel/fork.c:3198 [inline]
__se_sys_unshare kernel/fork.c:3196 [inline]
__x64_sys_unshare+0x31/0x40 kernel/fork.c:3196
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fce5c78eba9
RSP: 002b:00007fce5d666038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fce5c9d6180 RCX: 00007fce5c78eba9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000068040200
RBP: 00007fce5c811e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fce5c9d6218 R14: 00007fce5c9d6180 R15: 00007ffea78c0808
task:syz-executor state:R running task stack:28024 pid:15861 tgid:15861 ppid:10054 task_flags:0x400040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6961
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288
irqentry_exit+0x36/0x90 kernel/entry/common.c:197
asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:preempt_schedule+0x4/0x30 kernel/sched/core.c:7167
Code: 62 02 f6 eb c5 48 89 ef e8 a9 5a 8c f6 eb 97 e8 92 5b 8c f6 eb da 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa <65> 8b 05 75 2c 41 08 a9 ff ff ff 7f 74 05 e9 99 cc 01 00 9c 58 f6
RSP: 0000:ffffc90003a3fae0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff88802528eea0 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000001
RBP: ffffc90003a3fb30 R08: 0000000000000000 R09: ffffed1004a51dd4
R10: ffff88802528eea3 R11: 0000000000000000 R12: 0000000000000000
R13: ffffea000141f700 R14: ffff888028efd828 R15: ffffea000136b8c0
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+0x3e/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
wp_page_copy mm/memory.c:3653 [inline]
do_wp_page+0x177b/0x4f00 mm/memory.c:4013
handle_pte_fault mm/memory.c:6068 [inline]
__handle_mm_fault+0x1b2d/0x2a50 mm/memory.c:6195
handle_mm_fault+0x589/0xd10 mm/memory.c:6364
do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x5c/0xb0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f0bd52645b2
RSP: 002b:00007ffea45777a0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000005
RDX: 00007f0bd5413464 RSI: 0000000000000040 RDI: 00007ffea45778f0
RBP: 00007ffea45778f0 R08: 0000000000000702 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00000000000000f7
R13: 0000000000000000 R14: 00000000000e2259 R15: 00007ffea4577a50
rcu: rcu_preempt kthread timer wakeup didn't happen for 10644 jiffies! g62733 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=71414
rcu: rcu_preempt kthread starved for 10645 jiffies! g62733 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:27368 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7058
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285
kthread+0x3c2/0x780 kernel/kthread.c:463
ret_from_fork+0x56a/0x730 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:
CPU: 0 UID: 0 PID: 1298 Comm: aoe_tx0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 06 af 00 f6 48 89 df e8 ee 02 01 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 c5 ff f0 f5 65 8b 05 9e ac 3f 08 85 c0 74 16 5b
RSP: 0018:ffffc9000413f968 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffffffff9b117ba0 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8de52bd0 RDI: ffffffff8c163000
RBP: 0000000000000293 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90ab7297 R11: 0000000000000000 R12: ffffffff8f2eda40
R13: ffffffff9b117ca8 R14: 0000000000000000 R15: ffffffff9b117ce0
FS: 0000000000000000(0000) GS:ffff8881246b3000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff99578cc0 CR3: 000000005cf65000 CR4: 00000000003526f0
Call Trace:
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
uart_port_unlock_irqrestore include/linux/serial_core.h:788 [inline]
uart_port_unlock_deref drivers/tty/serial/serial_core.c:91 [inline]
uart_port_unlock_deref drivers/tty/serial/serial_core.c:88 [inline]
uart_write_room+0x2d9/0x940 drivers/tty/serial/serial_core.c:650
tty_write_room+0x66/0x90 drivers/tty/tty_ioctl.c:69
handle_tx+0x14f/0x630 drivers/net/caif/caif_serial.c:212
__netdev_start_xmit include/linux/netdevice.h:5222 [inline]
netdev_start_xmit include/linux/netdevice.h:5231 [inline]
xmit_one net/core/dev.c:3839 [inline]
dev_hard_start_xmit+0x94/0x740 net/core/dev.c:3855
__dev_queue_xmit+0xa46/0x4490 net/core/dev.c:4725
dev_queue_xmit include/linux/netdevice.h:3361 [inline]
tx+0xcc/0x190 drivers/block/aoe/aoenet.c:62
kthread+0x1e4/0x3e0 drivers/block/aoe/aoecmd.c:1241
kthread+0x3c2/0x780 kernel/kthread.c:463
ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245