rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P18789/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=85205, q=942104 ncpus=2)
task:syz.4.3363 state:R running task stack:25624 pid:18789 tgid:18771 ppid:17885 task_flags:0x400040 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5533 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7284
preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7606
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x14f/0x910 kernel/entry/common.c:167
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5947
Code: ff ff ff e8 40 2c 43 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 62 27 f2 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 7f 30 46 0a cc 48 8d 3d 87 60 da
RSP: 0018:ffffc9000529ef20 EFLAGS: 00000292
RAX: 051077a1b169af00 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 00000000105209fd RSI: ffffffff8e69efee RDI: ffffffff8c6dac80
RBP: ffff8880774e9f40 R08: ffffffff8177f1df R09: 0000000000000000
R10: ffffc9000529f058 R11: ffffffff81b293f0 R12: ffffffff8ed5c920
R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
rcu_read_lock include/linux/rcupdate.h:849 [inline]
class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
save_stack+0x122/0x230 mm/page_owner.c:183
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:338
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1418 [inline]
free_unref_folios+0xdc2/0x14e0 mm/page_alloc.c:3022
folios_put_refs+0x9e9/0xb30 mm/folio.c:1036
folio_batch_release include/linux/folio_batch.h:101 [inline]
shmem_undo_range+0x4e6/0x15d0 mm/shmem.c:1161
shmem_truncate_range mm/shmem.c:1289 [inline]
shmem_evict_inode+0x247/0xae0 mm/shmem.c:1420
evict+0x624/0xb50 fs/inode.c:822
dentry_kill+0x1b9/0x880 fs/dcache.c:826
finish_dput+0x1a/0x260 fs/dcache.c:1001
__fput+0x675/0xa50 fs/file_table.c:520
task_work_run+0x1d9/0x270 kernel/task_work.c:233
get_signal+0x1181/0x12c0 kernel/signal.c:2884
arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline]
do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f725679e159
RSP: 002b:00007f72549f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: 0000200000000000 RBX: 00007f7256a26450 RCX: 00007f725679e159
RDX: 0000000000000003 RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007f725683506b R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7256a264e8 R14: 00007f7256a26450 R15: 00007ffef18c2098
rcu: rcu_preempt kthread starved for 2175 jiffies! g85205 f0x2 RCU_GP_WAIT_FQS(5) ->state=R ->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:28096 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5533 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7284
__schedule_loop kernel/sched/core.c:7361 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7376
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 8365 Comm: kworker/u8:19 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: krds_cp_wq#2/5 rds_connect_worker
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x5b/0xb0 kernel/rcu/tree.c:753
Code: f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 2b 74 8b 00 48 c7 c3 18 9a 96 93 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 <84> c0 75 35 8b 03 65 48 ff 0d b7 f3 e8 11 74 11 83 e0 04 c1 e8 02
RSP: 0018:ffffc90000006df0 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: ffff8880b8633a18 RCX: 8000000000000102
RDX: 0000000000000000 RSI: ffffffff8c6dac60 RDI: ffffffff8c6dac20
RBP: 1ffff92000000dfc R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90000006fa8 R11: fffff52000000e01 R12: ffffffff8ed5c920
R13: 0000000000000002 R14: ffffffff8e6e97d0 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888124cca000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe2b7b1ee80 CR3: 00000000122d4000 CR4: 00000000003526f0
Call Trace:
trace_lock_acquire include/trace/events/lock.h:23 [inline]
lock_acquire+0x58/0x350 kernel/locking/lockdep.c:5905
rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
rcu_read_lock include/linux/rcupdate.h:849 [inline]
class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495
__unwind_start+0x514/0x660 arch/x86/kernel/unwind_orc.c:787
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
__call_rcu_common kernel/rcu/tree.c:3181 [inline]
call_rcu+0xee/0x8b0 kernel/rcu/tree.c:3301
refdst_drop include/net/dst.h:272 [inline]
skb_dst_drop include/net/dst.h:284 [inline]
skb_release_head_state+0x71/0x370 net/core/skbuff.c:1171
skb_release_all net/core/skbuff.c:1195 [inline]
__kfree_skb+0x24/0x210 net/core/skbuff.c:1211
nft_synproxy_eval_v4+0x36a/0x4e0 net/netfilter/nft_synproxy.c:-1
nft_synproxy_do_eval+0x389/0x5d0 net/netfilter/nft_synproxy.c:142
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x48d/0x1b10 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0x360/0x4b0 net/netfilter/nft_chain_filter.c:162
nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619
nf_hook include/linux/netfilter.h:280 [inline]
NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:323
NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:325
__netif_receive_skb_one_core net/core/dev.c:6265 [inline]
__netif_receive_skb net/core/dev.c:6378 [inline]
process_backlog+0xa6b/0x18b0 net/core/dev.c:6729
__napi_poll+0xaa/0x330 net/core/dev.c:7798
napi_poll net/core/dev.c:7861 [inline]
net_rx_action+0x61d/0xf50 net/core/dev.c:8018
handle_softirqs+0x226/0x860 kernel/softirq.c:645
do_softirq+0x77/0xd0 kernel/softirq.c:546
__local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473
__inet6_bind+0x386/0xf30 net/ipv6/af_inet6.c:419
kernel_bind+0x13e/0x1c0 net/socket.c:3675
rds_tcp_conn_path_connect+0x53b/0x920 net/rds/tcp_connect.c:175
rds_connect_worker+0x1d8/0x290 net/rds/threads.c:176
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245