rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P18245/1:b..l P20943/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=81637, q=277 ncpus=2)
task:syz.1.3089 state:R running task stack:28408 pid:20943 tgid:20943 ppid:5808 task_flags:0x400040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256
irqentry_exit+0x36/0x90 kernel/entry/common.c:211
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0xdf/0x20a0 arch/x86/kernel/unwind_orc.c:482
Code: c0 48 8d 05 00 00 00 00 50 b9 02 00 00 00 31 f6 48 c7 c7 60 44 3c 8e e8 5f d4 2c 00 e8 4a 31 f4 09 5a 85 c0 0f 85 57 09 00 00 <48> b8 00 00 00 00 00 fc ff df 4d 8d 65 50 4c 89 e2 48 c1 ea 03 80
RSP: 0000:ffffc900120d73b8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000032cf37bb
RDX: 0000000000000000 RSI: ffffffff8bf06c40 RDI: ffffffff8dcd3ee0
RBP: ffffc900120d7470 R08: de043fb5d4c0841e R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffffffff81a801e0
R13: ffffc900120d7428 R14: 0000000000000000 R15: ffff888078e38000
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
save_stack+0x160/0x1f0 mm/page_owner.c:156
__set_page_owner+0x91/0x560 mm/page_owner.c:332
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850
prep_new_page mm/page_alloc.c:1858 [inline]
get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884
__alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183
alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
alloc_frozen_pages_noprof mm/mempolicy.c:2487 [inline]
alloc_pages_noprof+0x131/0x390 mm/mempolicy.c:2507
pagetable_alloc_noprof include/linux/mm.h:2980 [inline]
__pte_alloc_one_noprof include/asm-generic/pgalloc.h:75 [inline]
pte_alloc_one+0x1e/0x350 arch/x86/mm/pgtable.c:18
__do_fault+0x320/0x490 mm/memory.c:5275
do_shared_fault mm/memory.c:5762 [inline]
do_fault mm/memory.c:5836 [inline]
do_pte_missing+0x1a6/0x3ba0 mm/memory.c:4361
handle_pte_fault mm/memory.c:6177 [inline]
__handle_mm_fault+0x1556/0x2aa0 mm/memory.c:6318
handle_mm_fault+0x589/0xd10 mm/memory.c:6487
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+0x64/0xc0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7fb5970659d3
RSP: 002b:00007ffc64790200 EFLAGS: 00010246
RAX: 00000000005ffde8 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000001b2f624000 RSI: 0000000000600000 RDI: 00007fb59729b090
RBP: 0000000000000000 R08: 0000000000000004 R09: 0000000000040000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000555566153590 R14: 0000000000196a00 R15: 00007ffc647904b0
task:udevd state:R running task stack:24728 pid:18245 tgid:18245 ppid:5183 task_flags:0x400140 flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7113
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0x61/0x80 kernel/locking/spinlock.c:194
sock_def_readable+0x15b/0x600 net/core/sock.c:3551
unix_dgram_sendmsg+0xd1b/0x17f0 net/unix/af_unix.c:2309
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
sock_write_iter+0x566/0x610 net/socket.c:1195
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x7d3/0x11d0 fs/read_write.c:686
ksys_write+0x1f8/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc424ea7407
RSP: 002b:00007fff2834e650 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc42568e880 RCX: 00007fc424ea7407
RDX: 0000000000000000 RSI: 00007fff2834e6f7 RDI: 000000000000000a
RBP: 000000000000000a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007fc42568e6e8
R13: 0000000000000000 R14: 0000000000000000 R15: 0000561e998610c0
rcu: rcu_preempt kthread timer wakeup didn't happen for 10557 jiffies! g81637 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=132620
rcu: rcu_preempt kthread starved for 10563 jiffies! g81637 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:28080 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
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: 1299 Comm: aoe_tx0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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 16 e9 35 f6 48 89 df e8 fe 3c 36 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 45 46 26 f6 65 8b 05 7e 65 3e 08 85 c0 74 16 5b
RSP: 0018:ffffc900043af968 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffffffff9add7200 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8da2a2a9 RDI: ffffffff8bf06cc0
RBP: 0000000000000293 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff9081f4d7 R11: 0000000000000001 R12: ffffffff9add7308
R13: 0000000000000003 R14: 0000000000000001 R15: 0000000000000003
FS: 0000000000000000(0000) GS:ffff888124a0a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3b5040 CR3: 0000000035194000 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+0x4c1/0xb30 drivers/tty/serial/serial_core.c:626
handle_tx+0x204/0x630 drivers/net/caif/caif_serial.c:222
__netdev_start_xmit include/linux/netdevice.h:5248 [inline]
netdev_start_xmit include/linux/netdevice.h:5257 [inline]
xmit_one net/core/dev.c:3845 [inline]
dev_hard_start_xmit+0x97/0x740 net/core/dev.c:3861
__dev_queue_xmit+0xa46/0x4490 net/core/dev.c:4763
dev_queue_xmit include/linux/netdevice.h:3365 [inline]
tx+0xcc/0x190 drivers/block/aoe/aoenet.c:62
kthread+0x1e4/0x3e0 drivers/block/aoe/aoecmd.c:1241
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245