rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P143/1:b..l P5753/3:b..l
rcu: (detected by 0, t=10502 jiffies, g=9617, q=498 ncpus=2)
task:syz-executor state:R running task stack:21936 pid:5753 ppid:5752 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867
preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
__local_bh_enable_ip+0x14b/0x1c0 kernel/softirq.c:413
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:856 [inline]
__dev_queue_xmit+0x1b2c/0x3660 net/core/dev.c:4490
dev_queue_xmit include/linux/netdevice.h:3113 [inline]
neigh_hh_output include/net/neighbour.h:527 [inline]
neigh_output include/net/neighbour.h:541 [inline]
ip_finish_output2+0xcec/0x11e0 net/ipv4/ip_output.c:235
NF_HOOK_COND include/linux/netfilter.h:293 [inline]
ip_output+0x2a1/0x3b0 net/ipv4/ip_output.c:436
dst_output include/net/dst.h:467 [inline]
ip_local_out net/ipv4/ip_output.c:129 [inline]
__ip_queue_xmit+0x1049/0x1950 net/ipv4/ip_output.c:540
__tcp_transmit_skb+0x1d6d/0x33f0 net/ipv4/tcp_output.c:1427
tcp_transmit_skb net/ipv4/tcp_output.c:1445 [inline]
tcp_write_xmit+0x174c/0x62e0 net/ipv4/tcp_output.c:2784
__tcp_push_pending_frames+0x97/0x340 net/ipv4/tcp_output.c:2969
tcp_push_pending_frames include/net/tcp.h:2012 [inline]
tcp_data_snd_check net/ipv4/tcp_input.c:5658 [inline]
tcp_rcv_established+0xfb0/0x1d20 net/ipv4/tcp_input.c:6092
tcp_v4_do_rcv+0x4ed/0xb80 net/ipv4/tcp_ipv4.c:1735
sk_backlog_rcv include/net/sock.h:1142 [inline]
__release_sock+0x1e5/0x460 net/core/sock.c:3011
release_sock+0x5f/0x1c0 net/core/sock.c:3550
tcp_sendmsg+0x39/0x50 net/ipv4/tcp.c:1349
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
sock_write_iter+0x2df/0x420 net/socket.c:1160
call_write_iter include/linux/fs.h:2018 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x46c/0x990 fs/read_write.c:584
ksys_write+0x150/0x260 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb236b57fd7
RSP: 002b:00007ffd57c34520 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000055557d5c9500 RCX: 00007fb236b57fd7
RDX: 0000000000022f20 RSI: 00007fb2321dd0e0 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000022f20
R13: 000055557d5dd860 R14: 00007ffd57c34ac0 R15: 00007fb2321dd0e0
task:kworker/u4:5 state:R running task stack:21712 pid:143 ppid:2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:percpu_counter_add_batch+0x259/0x2a0 lib/percpu_counter.c:103
Code: 4d 85 ff 75 16 e8 17 7a 2b fd eb 15 e8 10 7a 2b fd e8 9b 99 2b 06 4d 85 ff 74 ea e8 01 7a 2b fd fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 04 2e 00 00 00 00 43 c7 44 2e 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc90002da6ba0 EFLAGS: 00000293
RAX: ffffffff845bb1ef RBX: 0000000000000000 RCX: ffff88801abc3c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90002da6c90 R08: ffffffff911c95a7 R09: 1ffffffff22392b4
R10: dffffc0000000000 R11: fffffbfff22392b5 R12: 1ffff1100494902c
R13: dffffc0000000000 R14: 1ffff920005b4d7c R15: 0000000000000200
wb_stat_mod include/linux/backing-dev.h:67 [inline]
folio_clear_dirty_for_io+0x66f/0xc30 mm/page-writeback.c:2933
mpage_submit_folio+0x7d/0x3c0 fs/ext4/inode.c:1891
mpage_map_and_submit_buffers fs/ext4/inode.c:2156 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2295 [inline]
ext4_do_writepages+0x1d5c/0x3990 fs/ext4/inode.c:2720
ext4_writepages+0x1dd/0x350 fs/ext4/inode.c:2809
do_writepages+0x3b3/0x630 mm/page-writeback.c:2575
__writeback_single_inode+0x153/0xec0 fs/fs-writeback.c:1635
writeback_sb_inodes+0x7cd/0xf50 fs/fs-writeback.c:1926
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:1997
wb_writeback+0x47e/0xbf0 fs/fs-writeback.c:2107
wb_check_old_data_flush fs/fs-writeback.c:2211 [inline]
wb_do_writeback fs/fs-writeback.c:2264 [inline]
wb_workfn+0xad7/0xe60 fs/fs-writeback.c:2292
process_one_work kernel/workqueue.c:2653 [inline]
process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
rcu: rcu_preempt kthread starved for 10389 jiffies! g9617 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:27656 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148
Code: 68 20 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 43 f4 40 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80
RSP: 0018:ffffffff8ce07d80 EFLAGS: 000002c2
RAX: b645f1ec48a00100 RBX: ffffffff8162afbd RCX: b645f1ec48a00100
RDX: 0000000000000001 RSI: ffffffff8acacbe0 RDI: ffffffff8b1c9a20
RBP: ffffffff8ce07eb8 R08: ffff8880b8e36b2b R09: 1ffff110171c6d65
R10: dffffc0000000000 R11: ffffed10171c6d66 R12: 1ffffffff19c0fbc
R13: dffffc0000000000 R14: 1ffffffff19d2688 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe53261c38 CR3: 000000007f96b000 CR4: 00000000003506f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:753
default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
cpuidle_idle_call kernel/sched/idle.c:178 [inline]
do_idle+0x33d/0x590 kernel/sched/idle.c:302
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:401
rest_init+0x2e2/0x300 init/main.c:744
arch_call_rest_init+0xe/0x10 init/main.c:840
start_kernel+0x459/0x4e0 init/main.c:1085
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536
secondary_startup_64_no_verify+0x179/0x17b