[v5.15] INFO: rcu detected stall in console_trylock_spinning

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syzbot

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Jul 24, 2023, 7:36:09 PM7/24/23
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Hello,

syzbot found the following issue on:

HEAD commit: 5c6a716301d9 Linux 5.15.122
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14ba986ea80000
kernel config: https://syzkaller.appspot.com/x/.config?x=6383c61ced7235db
dashboard link: https://syzkaller.appspot.com/bug?extid=27c708fc6f939bcbb841
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f1933a471feb/disk-5c6a7163.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/121bfa84bd57/vmlinux-5c6a7163.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5c2483375147/bzImage-5c6a7163.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+27c708...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-...!: (8 ticks this GP) idle=53d/1/0x4000000000000000 softirq=35253/35255 fqs=0
(t=17960 jiffies g=60253 q=4572)
rcu: rcu_preempt kthread starved for 17960 jiffies! g60253 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:I stack:27000 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5026 [inline]
__schedule+0x12c4/0x4590 kernel/sched/core.c:6372
schedule+0x11b/0x1f0 kernel/sched/core.c:6455
schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1884
rcu_gp_fqs_loop+0x2af/0xf70 kernel/rcu/tree.c:1959
rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2132
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4226 Comm: kworker/1:10 Not tainted 5.15.122-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
Workqueue: rcu_gp wait_rcu_exp_gp
RIP: 0010:__in6_dev_get include/net/addrconf.h:313 [inline]
RIP: 0010:ip6_ignore_linkdown include/net/addrconf.h:404 [inline]
RIP: 0010:find_match+0xb0/0xc20 net/ipv6/route.c:738
Code: 80 3c 38 00 74 08 48 89 ef e8 dc d0 cb f8 4c 89 64 24 30 48 89 e8 bd 60 03 00 00 48 03 28 48 89 e8 48 c1 e8 03 42 80 3c 38 00 <74> 08 48 89 ef e8 b6 d0 cb f8 4c 8b 65 00 e8 6d 7c 1e 01 89 c5 31
RSP: 0018:ffffc90000dd0050 EFLAGS: 00000246
RAX: 1ffff11005b2e46c RBX: ffff888022260ca8 RCX: ffff888078bc0000
RDX: ffff888078bc0000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88802d972360 R08: ffffffff88fda160 R09: ffffc90000dd0370
R10: ffffc90000dd0360 R11: dffffc0000000001 R12: ffffc90000dd0370
R13: ffff888022260cb7 R14: 1ffff1100444c196 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005629edf54030 CR3: 00000000790da000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<IRQ>
__find_rr_leaf+0x271/0x8e0 net/ipv6/route.c:826
find_rr_leaf net/ipv6/route.c:847 [inline]
rt6_select net/ipv6/route.c:891 [inline]
fib6_table_lookup+0x453/0xbf0 net/ipv6/route.c:2185
ip6_pol_route+0x1e7/0x15a0 net/ipv6/route.c:2221
pol_lookup_func include/net/ip6_fib.h:582 [inline]
fib6_rule_lookup+0x265/0x620 net/ipv6/fib6_rules.c:115
ip6_route_input_lookup net/ipv6/route.c:2291 [inline]
ip6_route_input+0x82d/0xd90 net/ipv6/route.c:2587
ip6_rcv_finish+0x136/0x250 net/ipv6/ip6_input.c:77
NF_HOOK+0x364/0x410 include/linux/netfilter.h:302
__netif_receive_skb_one_core net/core/dev.c:5462 [inline]
__netif_receive_skb+0x1c6/0x530 net/core/dev.c:5576
process_backlog+0x363/0x7f0 net/core/dev.c:6453
__napi_poll+0xc7/0x440 net/core/dev.c:7012
napi_poll net/core/dev.c:7079 [inline]
net_rx_action+0x617/0xda0 net/core/dev.c:7166
__do_softirq+0x3b3/0x93a kernel/softirq.c:558
invoke_softirq kernel/softirq.c:432 [inline]
__irq_exit_rcu+0x155/0x240 kernel/softirq.c:636
irq_exit_rcu+0x5/0x20 kernel/softirq.c:648
sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1096
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:console_trylock_spinning+0x36b/0x3f0 kernel/printk/printk.c:1909
Code: 0f 84 75 ff ff ff e8 54 f3 19 00 fb 31 db eb 41 e8 4a f3 19 00 e8 65 0b b6 08 4d 85 ed 74 cd e8 3b f3 19 00 fb bb 01 00 00 00 <48> c7 c7 e0 b1 7f 8c 31 f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00
RSP: 0018:ffffc900050df8e0 EFLAGS: 00000293
RAX: ffffffff81660d35 RBX: 0000000000000001 RCX: ffff888078bc0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900050df9b0 R08: ffffffff81660cee R09: fffffbfff1f7aa25
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000a1bf1c
R13: 0000000000000200 R14: 0000000000000046 R15: dffffc0000000000
vprintk_emit+0xa1/0x150 kernel/printk/printk.c:2267
_printk+0xd1/0x111 kernel/printk/printk.c:2289
synchronize_rcu_expedited_wait kernel/rcu/tree_exp.h:545 [inline]
rcu_exp_wait_wake kernel/rcu/tree_exp.h:587 [inline]
rcu_exp_sel_wait_wake+0x107c/0x1c00 kernel/rcu/tree_exp.h:621
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
</TASK>
NMI backtrace for cpu 0
CPU: 0 PID: 11054 Comm: syz-executor.3 Not tainted 5.15.122-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
rcu_dump_cpu_stacks+0x223/0x390 kernel/rcu/tree_stall.h:343
print_cpu_stall kernel/rcu/tree_stall.h:627 [inline]
check_cpu_stall kernel/rcu/tree_stall.h:711 [inline]
rcu_pending kernel/rcu/tree.c:3911 [inline]
rcu_sched_clock_irq+0xf26/0x1770 kernel/rcu/tree.c:2606
update_process_times+0x196/0x200 kernel/time/timer.c:1788
tick_sched_handle kernel/time/tick-sched.c:237 [inline]
tick_sched_timer+0x22d/0x3c0 kernel/time/tick-sched.c:1441
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline]
__sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102
sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f1 9e f6 ff 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 de 19 3d f7 48 89 df e8 76 6c 3e f7 e8 d1 fa 60 f7 fb bf 01 00 00 00 <e8> f6 a9 31 f7 65 8b 05 07 f6 dc 75 85 c0 74 02 5b c3 e8 94 0d db
RSP: 0018:ffffc900053a76f0 EFLAGS: 00000286
RAX: 47d360d711091500 RBX: ffff888031cb8358 RCX: ffffffff8162daf8
RDX: dffffc0000000000 RSI: ffffffff8a8b01e0 RDI: 0000000000000001
RBP: ffffc900053a7870 R08: dffffc0000000000 R09: fffffbfff1f7aa33
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc900053a77c0
R13: ffffea0000fc1f00 R14: dffffc0000000000 R15: 0000000000000001
spin_unlock_irq include/linux/spinlock.h:413 [inline]
shmem_add_to_page_cache+0x12aa/0x17c0 mm/shmem.c:752
shmem_getpage_gfp+0x1aa1/0x3190 mm/shmem.c:1940
shmem_getpage mm/shmem.c:151 [inline]
shmem_write_begin+0xce/0x1a0 mm/shmem.c:2477
generic_perform_write+0x2bf/0x5b0 mm/filemap.c:3776
__generic_file_write_iter+0x243/0x4f0 mm/filemap.c:3903
generic_file_write_iter+0xa7/0x1b0 mm/filemap.c:3935
call_write_iter include/linux/fs.h:2103 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0xacf/0xe50 fs/read_write.c:594
ksys_write+0x1a2/0x2c0 fs/read_write.c:647
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f0153fba86f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 b9 80 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 0c 81 02 00 48
RSP: 002b:00007f015253ce70 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007f0153fba86f
RDX: 0000000001000000 RSI: 00007f014a11d000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000005593
R10: 0000000020005682 R11: 0000000000000293 R12: 0000000000000003
R13: 00007f015253cf3c R14: 00007f015253cf40 R15: 00007f014a11d000
</TASK>


---
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syzbot

unread,
Nov 1, 2023, 7:35:15 PM11/1/23
to syzkaller...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
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