rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8613/2:b..l P8620/4:b..l
rcu: (detected by 1, t=10502 jiffies, g=24997, q=248 ncpus=2)
task:syz.2.732 state:R running task stack:24936 pid:8620 tgid:8614 ppid:5815 task_flags:0x400140 flags:0x00080002
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: 2b 13 12 83 f8 07 0f 87 a2 02 00 00 89 c0 48 0f a3 05 d2 ce ed 0e 0f 82 74 02 00 00 8b 35 6a ff ed 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 e9 2a 13 12 0f 85 ad 02 00 00 48 83 c4
RSP: 0000:ffffc90004a9ed28 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e3c9240 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8da99eef RDI: ffffffff8bf22980
RBP: 0000000000000002 R08: 000000007f45ee1d R09: 000000009529a683
R10: ffff888053472ff0 R11: 0000000039529a68 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
kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:252 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284
kasan_slab_free include/linux/kasan.h:234 [inline]
slab_free_hook mm/slub.c:2540 [inline]
slab_free mm/slub.c:6663 [inline]
kmem_cache_free+0x2d8/0x770 mm/slub.c:6774
skb_kfree_head net/core/skbuff.c:1066 [inline]
skb_kfree_head net/core/skbuff.c:1063 [inline]
skb_free_head+0x1b7/0x210 net/core/skbuff.c:1080
skb_release_data+0x5ce/0x7a0 net/core/skbuff.c:1107
skb_release_all net/core/skbuff.c:1182 [inline]
__kfree_skb net/core/skbuff.c:1196 [inline]
sk_skb_reason_drop+0x129/0x1a0 net/core/skbuff.c:1234
kfree_skb_reason include/linux/skbuff.h:1322 [inline]
kfree_skb include/linux/skbuff.h:1331 [inline]
ip6_finish_output2+0xcd7/0x1cf0 net/ipv6/ip6_output.c:109
__ip6_finish_output+0x3cd/0x1010 net/ipv6/ip6_output.c:209
ip6_finish_output net/ipv6/ip6_output.c:220 [inline]
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip6_output+0x253/0x710 net/ipv6/ip6_output.c:247
ip6_mr_output+0x233/0x11b0 net/ipv6/ip6mr.c:2415
dst_output include/net/dst.h:464 [inline]
dst_output include/net/dst.h:462 [inline]
ip6_local_out+0x2a9/0x4d0 net/ipv6/output_core.c:157
ip6_send_skb+0x112/0x460 net/ipv6/ip6_output.c:1994
udp_v6_send_skb+0x96f/0x1910 net/ipv6/udp.c:1441
udpv6_sendmsg+0x23b1/0x2d30 net/ipv6/udp.c:1732
inet6_sendmsg+0x105/0x140 net/ipv6/af_inet6.c:659
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0x705/0xc30 net/socket.c:2592
___sys_sendmsg+0x134/0x1d0 net/socket.c:2646
__sys_sendmmsg+0x200/0x420 net/socket.c:2735
__do_sys_sendmmsg net/socket.c:2762 [inline]
__se_sys_sendmmsg net/socket.c:2759 [inline]
__x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2759
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: 0033:0x7f50ce38f749
RSP: 002b:00007f50cf29a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f50ce5e6180 RCX: 00007f50ce38f749
RDX: 0400000000000172 RSI: 0000200000003cc0 RDI: 0000000000000009
RBP: 00007f50ce413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000004000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f50ce5e6218 R14: 00007f50ce5e6180 R15: 00007ffcf203bb28
task:syz.4.731 state:X running task stack:25312 pid:8613 tgid:8613 ppid:0 task_flags:0x40004c flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
preempt_schedule_notrace+0x62/0xe0 kernel/sched/core.c:7140
preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:752
trace_lock_release include/trace/events/lock.h:69 [inline]
lock_release+0x201/0x2d0 kernel/locking/lockdep.c:5879
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock+0x1c/0x60 include/linux/rcupdate.h:897
percpu_ref_tryget_many include/linux/percpu-refcount.h:250 [inline]
percpu_ref_tryget include/linux/percpu-refcount.h:266 [inline]
css_tryget include/linux/cgroup_refcnt.h:45 [inline]
css_tryget include/linux/cgroup_refcnt.h:42 [inline]
get_mem_cgroup_from_objcg+0x12f/0x210 include/linux/memcontrol.h:520
obj_cgroup_uncharge_pages+0x13/0x1e0 mm/memcontrol.c:2797
__memcg_kmem_uncharge_page+0x3b/0x1c0 mm/memcontrol.c:2890
memcg_kmem_uncharge_page include/linux/memcontrol.h:1718 [inline]
exit_task_stack_account+0xb7/0x110 kernel/fork.c:465
do_exit+0x1586/0x2bd0 kernel/exit.c:1006
do_group_exit+0xd3/0x2a0 kernel/exit.c:1114
__do_sys_exit_group kernel/exit.c:1125 [inline]
__se_sys_exit_group kernel/exit.c:1123 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1123
x64_sys_call+0x151c/0x1740 arch/x86/include/generated/asm/syscalls_64.h:232
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: 0033:0x7fd1b9f8f749
RSP: 002b:00007ffc5b2552a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd1b9f8f749
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffc5b25530c R08: 0000001c5b25539f R09: 00005555568ab590
R10: 0000000000000001 R11: 0000000000000246 R12: 000000000000008c
R13: 00005555568ab590 R14: 000000000004a570 R15: 00007ffc5b255360
rcu: rcu_preempt kthread starved for 10570 jiffies! g24997 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:28064 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 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
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: e6 6e 02 c3 cc cc cc cc 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 53 65 22 00 fb f4 cc 2f 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197de8 EFLAGS: 000002c6
RAX: 0000000001603049 RBX: 0000000000000001 RCX: ffffffff8b67f6d9
RDX: 0000000000000000 RSI: ffffffff8dabfef6 RDI: ffffffff8bf22980
RBP: ffffed1003b56498 R08: 0000000000000001 R09: ffffed10170a673d
R10: ffff8880b85339eb R11: 00000000ffffffff R12: 0000000000000001
R13: ffff88801dab24c0 R14: ffffffff908743d0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888124a56000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f706a5ce794 CR3: 000000007fe47000 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