rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6709/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=12397, q=502 ncpus=2)
task:syz.0.204 state:R running task stack:25128 pid:6709 tgid:6704 ppid:5815 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190
irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x62/0x330 kernel/locking/lockdep.c:5872
Code: 8f 12 12 83 f8 07 0f 87 a2 02 00 00 89 c0 48 0f a3 05 e2 ac ed 0e 0f 82 74 02 00 00 8b 35 5a dd ed 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 f9 8e 12 12 0f 85 ad 02 00 00 48 83 c4
RSP: 0018:ffffc9000ca7ed10 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e3c92c0 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8da973d4 RDI: ffffffff8bf21180
RBP: 0000000000000002 R08: 000000005a44979c R09: 00000000ffffffff
R10: ffff8880281e2ff0 R11: 00000000ffffffff R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
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+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479
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:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
unpoison_slab_object mm/kasan/common.c:342 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:368
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4948 [inline]
slab_alloc_node mm/slub.c:5258 [inline]
kmem_cache_alloc_node_noprof+0x28a/0x7f0 mm/slub.c:5310
kmalloc_reserve+0x18b/0x2c0 net/core/skbuff.c:586
__alloc_skb+0x186/0x410 net/core/skbuff.c:690
alloc_skb include/linux/skbuff.h:1383 [inline]
sock_omalloc+0xf5/0x1e0 net/core/sock.c:2856
msg_zerocopy_alloc net/core/skbuff.c:1704 [inline]
msg_zerocopy_realloc+0x200/0x8f0 net/core/skbuff.c:1781
__ip6_append_data+0x3c10/0x4740 net/ipv6/ip6_output.c:1540
ip6_make_skb+0x2c8/0x3f0 net/ipv6/ip6_output.c:2072
udpv6_sendmsg+0x2365/0x2d30 net/ipv6/udp.c:1726
inet6_sendmsg+0x105/0x140 net/ipv6/af_inet6.c:659
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:733 [inline]
____sys_sendmsg+0x705/0xc30 net/socket.c:2583
___sys_sendmsg+0x134/0x1d0 net/socket.c:2637
__sys_sendmmsg+0x200/0x420 net/socket.c:2726
__do_sys_sendmmsg net/socket.c:2753 [inline]
__se_sys_sendmmsg net/socket.c:2750 [inline]
__x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2750
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1875d8f749
RSP: 002b:00007f1873fb4038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f1875fe6180 RCX: 00007f1875d8f749
RDX: 0400000000000172 RSI: 0000200000003cc0 RDI: 000000000000000c
RBP: 00007f1875e13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000004000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1875fe6218 R14: 00007f1875fe6180 R15: 00007fff9ce24068
rcu: rcu_preempt kthread starved for 10547 jiffies! g12397 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:28456 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6960
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+0x983/0xb10 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: 1 UID: 0 PID: 0 Comm: swapper/1 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+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 76 70 02 e9 93 2f 03 00 0f 1f 00 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 13 13 24 00 fb f4 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197de8 EFLAGS: 000002c2
RAX: 00000000012fcf95 RBX: 0000000000000001 RCX: ffffffff8b6646f9
RDX: 0000000000000000 RSI: ffffffff8dabd2db RDI: ffffffff8bf21180
RBP: ffffed1003b55498 R08: 0000000000000001 R09: ffffed10170a671d
R10: ffff8880b85338eb R11: 00000000ffffffff R12: 0000000000000001
R13: ffff88801daaa4c0 R14: ffffffff90871dd0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888124a60000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b306fcff8 CR3: 00000000222e0000 CR4: 00000000003526f0
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+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x38d/0x510 kernel/sched/idle.c:332
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x148