rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11033/1:b..l P11028/1:b..l P10245/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=49377, q=412 ncpus=2)
task:udevd state:R running task stack:23168 pid:10245 tgid:10245 ppid:5197 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6864
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7048
preempt_schedule+0xae/0xc0 kernel/sched/core.c:7072
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+0xfd/0x110 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
__wake_up_common_lock+0x190/0x1f0 kernel/sched/wait.c:127
sock_def_readable+0x1eb/0x530 net/core/sock.c:3611
unix_dgram_sendmsg+0xdfb/0x1840 net/unix/af_unix.c:2286
sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:728
__sock_sendmsg net/socket.c:743 [inline]
sock_write_iter+0x2d9/0x3d0 net/socket.c:1201
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3c0d7d6407
RSP: 002b:00007ffcee5d1e30 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f3c0d74a880 RCX: 00007f3c0d7d6407
RDX: 0000000000000000 RSI: 00007ffcee5d1ed7 RDI: 000000000000000a
RBP: 000000000000000a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007f3c0d74a6e8
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
task:udevadm state:R running task stack:24312 pid:11028 tgid:11028 ppid:10244 task_flags:0x400000 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6864
preempt_schedule_notrace+0xd1/0x110 kernel/sched/core.c:7141
preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:752
rcu_read_lock_held_common kernel/rcu/update.c:109 [inline]
rcu_read_lock_held+0x15/0x50 kernel/rcu/update.c:349
kernfs_root+0xf6/0x230 fs/kernfs/kernfs-internal.h:76
kernfs_iop_permission+0x6c/0x430 fs/kernfs/inode.c:287
do_inode_permission fs/namei.c:526 [inline]
inode_permission+0x41f/0x5f0 fs/namei.c:596
lookup_inode_permission_may_exec fs/namei.c:636 [inline]
may_lookup fs/namei.c:1900 [inline]
link_path_walk+0xaad/0x18d0 fs/namei.c:2537
path_lookupat+0xe4/0x8c0 fs/namei.c:2745
filename_lookup+0x212/0x570 fs/namei.c:2775
do_readlinkat+0xd9/0x500 fs/stat.c:576
__do_sys_readlink fs/stat.c:613 [inline]
__se_sys_readlink fs/stat.c:610 [inline]
__x64_sys_readlink+0x7f/0x90 fs/stat.c:610
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbd141153a7
RSP: 002b:00007fffae01a578 EFLAGS: 00000202 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007fffae01adc0 RCX: 00007fbd141153a7
RDX: 0000000000000400 RSI: 00007fffae01a980 RDI: 00007fffae01a580
RBP: 0000000000000200 R08: 00005644586adae2 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007fffae01a580
R13: 00007fffae01a980 R14: 0000564475772d60 R15: 0000564475782e60
task:syz.0.1295 state:R running task stack:26456 pid:11033 tgid:11030 ppid:5825 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6864
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7191
irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 74 97 de 10 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc9000b9ef298 EFLAGS: 00000206
RAX: a0c2349a35b2e600 RBX: 0000000000000000 RCX: a0c2349a35b2e600
RDX: 000000000661e615 RSI: ffffffff8d969d83 RDI: ffffffff8bc018e0
RBP: ffffffff81743f85 R08: ffffffff81743f85 R09: ffffffff8df419e0
R10: ffffc9000b9ef458 R11: ffffffff81ada230 R12: 0000000000000002
R13: ffffffff8df419e0 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
poison_kmalloc_redzone mm/kasan/common.c:397 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414
kasan_kmalloc include/linux/kasan.h:262 [inline]
__kmalloc_cache_noprof+0x3e2/0x700 mm/slub.c:5771
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
genradix_alloc_node include/linux/generic-radix-tree.h:101 [inline]
__genradix_ptr_alloc+0x352/0x4a0 lib/generic-radix-tree.c:69
__genradix_prealloc+0x44/0x90 lib/generic-radix-tree.c:216
sctp_stream_alloc_out net/sctp/stream.c:104 [inline]
sctp_stream_init+0x14b/0x440 net/sctp/stream.c:149
sctp_association_init net/sctp/associola.c:232 [inline]
sctp_association_new+0x10dd/0x25e0 net/sctp/associola.c:296
sctp_connect_new_asoc+0x2c5/0x690 net/sctp/socket.c:1092
sctp_sendmsg_new_asoc net/sctp/socket.c:1692 [inline]
sctp_sendmsg+0x155c/0x2840 net/sctp/socket.c:2003
sock_sendmsg_nosec+0x128/0x1d0 net/socket.c:728
__sock_sendmsg net/socket.c:743 [inline]
__sys_sendto+0x3ce/0x540 net/socket.c:2212
__do_sys_sendto net/socket.c:2219 [inline]
__se_sys_sendto net/socket.c:2215 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2215
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f01c798f749
RSP: 002b:00007f01c8746038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f01c7be5fa0 RCX: 00007f01c798f749
RDX: 0000000000000001 RSI: 0000200000000580 RDI: 0000000000000006
RBP: 00007f01c7a13f91 R08: 0000200000000280 R09: 000000000000001c
R10: 000000000000c001 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f01c7be6038 R14: 00007f01c7be5fa0 R15: 00007fff79d908e8
rcu: rcu_preempt kthread starved for 10558 jiffies! g49377 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:27072 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6864
__schedule_loop kernel/sched/core.c:6946 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6961
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+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 93 ef 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 73 f0 0e 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c6
RAX: 1293a24bdc1e8500 RBX: ffffffff8197913a RCX: 1293a24bdc1e8500
RDX: 0000000000000001 RSI: ffffffff8d783537 RDI: ffffffff8bc018e0
RBP: ffffffff8dc07ea8 R08: ffff8880b86336db R09: 1ffff110170c66db
R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8f813370
R13: 1ffffffff1b92a68 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125e4f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f72dd040b11 CR3: 000000000dd3a000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x1ea/0x520 kernel/sched/idle.c:332
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
rest_init+0x2de/0x300 init/main.c:757
start_kernel+0x3a7/0x400 init/main.c:1206
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147