ip6_tunnel: ip6gretap0: Local routing loop detected!
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P17489/1:b..l
rcu: (detected by 0, t=10503 jiffies, g=104177, q=863086 ncpus=2)
task:syz.0.2824 state:R running task stack:24104 pid:17489 tgid:17488 ppid:14894 task_flags:0x400140 flags:0x00004006
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x175/0x360 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 9b 52 03 11 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc9000b3a7638 EFLAGS: 00000206
RAX: bcc6c0329bf20c00 RBX: 0000000000000000 RCX: bcc6c0329bf20c00
RDX: 0000000000000000 RSI: ffffffff8dba97f4 RDI: ffffffff8be34700
RBP: ffffffff84b2b83d R08: 0000000000000000 R09: ffffffff84b2b83d
R10: dffffc0000000000 R11: fffff94000281f27 R12: 0000000000000002
R13: ffffffff8e139ee0 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:841 [inline]
blk_cgroup_congested+0x39/0x210 block/blk-cgroup.c:2255
__folio_throttle_swaprate+0x80/0x1c0 mm/swapfile.c:3915
folio_throttle_swaprate include/linux/swap.h:653 [inline]
shmem_add_to_page_cache+0x6f1/0xba0 mm/shmem.c:919
shmem_alloc_and_add_folio+0x846/0xf60 mm/shmem.c:1973
shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2597
shmem_get_folio mm/shmem.c:2703 [inline]
shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3353
generic_perform_write+0x2c5/0x900 mm/filemap.c:4176
shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3528
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c6/0xb30 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/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6a1018d69f
RSP: 002b:00007f6a11013df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000004000000 RCX: 00007f6a1018d69f
RDX: 0000000004000000 RSI: 00007f6a05e00000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000105fa
R10: 00000000000000d2 R11: 0000000000000293 R12: 0000000000000003
R13: 00007f6a11013ef0 R14: 00007f6a11013eb0 R15: 00007f6a05e00000
rcu: rcu_preempt kthread starved for 310 jiffies! g104177 f0x2 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:26496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
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+0x3f9/0x770 arch/x86/kernel/process.c:148
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: 15 Comm: ksoftirqd/0 Not tainted 6.16.0-next-20250808-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:58 [inline]
RIP: 0010:stack_access_ok arch/x86/kernel/unwind_orc.c:393 [inline]
RIP: 0010:deref_stack_reg+0xa5/0x230 arch/x86/kernel/unwind_orc.c:403
Code: 00 00 00 fc ff df 4c 89 74 24 08 4d 8b 77 10 4c 89 fd 48 c1 ed 03 0f b6 44 35 00 84 c0 0f 85 3c 01 00 00 41 83 3f 00 0f 95 c0 <4c> 39 c3 0f 96 c1 20 c1 4d 39 c6 0f 97 c0 20 c8 3c 01 75 18 49 8d
RSP: 0018:ffffc900001462e0 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffc90000140000 RCX: 0000000000000000
RDX: ffffc90000146448 RSI: dffffc0000000000 RDI: ffffc90000146408
RBP: 1ffff92000028c81 R08: ffffc90000146b50 R09: 0000000000000000
R10: ffffc90000146458 R11: fffff52000028c8d R12: 1ffff92000028c82
R13: 1ffff92000028c83 R14: ffffc90000148000 R15: ffffc90000146408
FS: 0000000000000000(0000) GS:ffff888125c15000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555628705c8 CR3: 000000000df36000 CR4: 00000000003526f0
Call Trace:
unwind_next_frame+0x17c4/0x2390 arch/x86/kernel/unwind_orc.c:-1
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:47 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:388 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:405
kasan_kmalloc include/linux/kasan.h:260 [inline]
__kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4396
kmalloc_noprof include/linux/slab.h:905 [inline]
kzalloc_noprof include/linux/slab.h:1039 [inline]
ref_tracker_alloc+0x133/0x460 lib/ref_tracker.c:271
__netdev_tracker_alloc include/linux/netdevice.h:4346 [inline]
netdev_hold include/linux/netdevice.h:4375 [inline]
dst_init+0xd9/0x450 net/core/dst.c:52
dst_alloc+0x12a/0x170 net/core/dst.c:93
rt_dst_alloc net/ipv4/route.c:1645 [inline]
__mkroute_output net/ipv4/route.c:2645 [inline]
ip_route_output_key_hash_rcu+0x14e1/0x23d0 net/ipv4/route.c:2866
ip_route_output_key_hash+0x1b9/0x2e0 net/ipv4/route.c:2696
__ip_route_output_key include/net/route.h:169 [inline]
ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2923
ip_route_output_key include/net/route.h:179 [inline]
ip_route_me_harder+0x6d2/0x1030 net/ipv4/netfilter.c:53
synproxy_send_tcp+0x359/0x6c0 net/netfilter/nf_synproxy_core.c:431
synproxy_send_client_synack+0x8bb/0xe20 net/netfilter/nf_synproxy_core.c:484
nft_synproxy_eval_v4+0x36e/0x560 net/netfilter/nft_synproxy.c:59
nft_synproxy_do_eval+0x345/0x570 net/netfilter/nft_synproxy.c:141
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x409/0x1920 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0x25d/0x340 net/netfilter/nft_chain_filter.c:161
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:316
NF_HOOK+0x309/0x3a0 include/linux/netfilter.h:318
__netif_receive_skb_one_core net/core/dev.c:5979 [inline]
__netif_receive_skb+0x143/0x380 net/core/dev.c:6092
process_backlog+0x60e/0x14f0 net/core/dev.c:6444
__napi_poll+0xc4/0x360 net/core/dev.c:7489
napi_poll net/core/dev.c:7552 [inline]
net_rx_action+0x707/0xe30 net/core/dev.c:7679
handle_softirqs+0x283/0x870 kernel/softirq.c:579
run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968
smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245