rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 ticks this GP) idle=15cc/1/0x4000000000000000 softirq=85480/85480 fqs=4
rcu: (detected by 0, t=10502 jiffies, g=80801, q=130 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 16470 Comm: syz.4.2818 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:mark_usage kernel/locking/lockdep.c:4620 [inline]
RIP: 0010:__lock_acquire+0x35c/0x1c90 kernel/locking/lockdep.c:5191
Code: 6a 3d 12 14 72 ab 8b 05 82 e8 1a 19 85 c0 0f 84 f8 00 00 00 31 c9 eb a9 44 38 fa 73 0d e8 5c 20 10 03 85 c0 0f 85 b7 05 00 00 <44> 8b 04 24 45 85 c0 74 74 41 80 7d 21 00 41 0f b6 45 22 78 2a a8
RSP: 0018:ffffc90000a08bc8 EFLAGS: 00000046
RAX: 0000000000000002 RBX: 0000000000000002 RCX: ffffffff95aba2b0
RDX: 0000000000000002 RSI: 0000000000000002 RDI: ffff888057d8d480
RBP: ffff888057d8c900 R08: 0000000000080000 R09: 0000000000000001
R10: 0000000000000050 R11: 0000000000000001 R12: ffff888057d8d430
R13: ffff888057d8d480 R14: 0000000000000002 R15: 0000000000000002
FS: 00007f716c2bc6c0(0000) GS:ffff888124ad8000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000395030 CR3: 000000007e1dc000 CR4: 00000000003526f0
Call Trace:
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
debug_object_activate+0x14c/0x4c0 lib/debugobjects.c:818
debug_hrtimer_activate kernel/time/hrtimer.c:438 [inline]
debug_activate kernel/time/hrtimer.c:477 [inline]
enqueue_hrtimer+0x23/0x3b0 kernel/time/hrtimer.c:1081
__run_hrtimer kernel/time/hrtimer.c:1794 [inline]
__hrtimer_run_queues+0x8ff/0xad0 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1058
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
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 c9 2f f6 48 89 df e8 fe 1c 30 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 45 26 20 f6 65 8b 05 7e 25 3b 08 85 c0 74 16 5b
RSP: 0018:ffffc9000f8bf760 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffff88802cac8100 RCX: 0000000000000006
RDX: 0000000000000000 RSI: ffffffff8db03325 RDI: ffffffff8bf1dec0
RBP: 0000000000000246 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff908313d7 R11: 0000000000000001 R12: ffff8880759fa280
R13: 0000000000000246 R14: ffff88802cac80e8 R15: ffffc9000f8bf8e8
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
__skb_try_recv_datagram+0x172/0x4f0 net/core/datagram.c:267
__unix_dgram_recvmsg+0x1bc/0xc30 net/unix/af_unix.c:2601
unix_dgram_recvmsg+0xd0/0x110 net/unix/af_unix.c:2700
sock_recvmsg_nosec net/socket.c:1078 [inline]
____sys_recvmsg+0x5f9/0x6b0 net/socket.c:2848
___sys_recvmsg+0x114/0x1a0 net/socket.c:2892
do_recvmmsg+0x2fe/0x750 net/socket.c:2987
__sys_recvmmsg net/socket.c:3061 [inline]
__do_sys_recvmmsg net/socket.c:3084 [inline]
__se_sys_recvmmsg net/socket.c:3077 [inline]
__x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3077
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: 0033:0x7f716b38efc9
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:00007f716c2bc038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f716b5e5fa0 RCX: 00007f716b38efc9
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007f716b411f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f716b5e6038 R14: 00007f716b5e5fa0 R15: 00007ffedb32c6e8
rcu: rcu_preempt kthread starved for 7081 jiffies! g80801 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:27816 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: 2984 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xdfd/0x1600 kernel/smp.c:877
Code: 57 48 8b 54 24 10 4c 89 74 24 10 49 89 d5 48 89 d5 48 89 54 24 18 49 c1 ed 03 83 e5 07 4d 01 e5 83 c5 03 e8 b5 0c 0c 00 f3 90 <41> 0f b6 45 00 40 38 c5 7c 08 84 c0 0f 85 e0 05 00 00 8b 43 08 31
RSP: 0018:ffffc9000c4e6858 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b8540320 RCX: ffffffff81b13d91
RDX: ffff888030772480 RSI: ffffffff81b13d6b RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000
R13: ffffed10170a8065 R14: 0000000000000001 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8881249d8000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc023812990 CR3: 000000007e1dc000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1043
__flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1381 [inline]
flush_tlb_mm_range+0x4a0/0x17a0 arch/x86/mm/tlb.c:1471
flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline]
ptep_clear_flush+0x136/0x180 mm/pgtable-generic.c:101
page_vma_mkclean_one.constprop.0+0x3b4/0x7e0 mm/rmap.c:1041
page_mkclean_one+0x196/0x260 mm/rmap.c:1082
__rmap_walk_file+0x359/0x620 mm/rmap.c:2918
rmap_walk_file+0x174/0x1f0 mm/rmap.c:2951
rmap_walk mm/rmap.c:2962 [inline]
folio_mkclean+0x251/0x3f0 mm/rmap.c:1114
folio_clear_dirty_for_io+0x153/0x790 mm/page-writeback.c:2938
mpage_submit_folio+0x84/0x2d0 fs/ext4/inode.c:2061
mpage_process_page_bufs+0x47c/0x8d0 fs/ext4/inode.c:2191
mpage_prepare_extent_to_map+0x79f/0x14d0 fs/ext4/inode.c:2736
ext4_do_writepages+0xa11/0x3cf0 fs/ext4/inode.c:2877
ext4_writepages+0x37a/0x7d0 fs/ext4/inode.c:3025
do_writepages+0x27a/0x600 mm/page-writeback.c:2604
__writeback_single_inode+0x160/0xfb0 fs/fs-writeback.c:1719
writeback_sb_inodes+0x60d/0xfa0 fs/fs-writeback.c:2015
__writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2086
wb_writeback+0x7f3/0xb70 fs/fs-writeback.c:2197
wb_check_old_data_flush fs/fs-writeback.c:2301 [inline]
wb_do_writeback fs/fs-writeback.c:2354 [inline]
wb_workfn+0x8ca/0xbe0 fs/fs-writeback.c:2382
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
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