[syzbot] [bpf?] [net?] INFO: rcu detected stall in handle_softirqs

From: syzbot
Date: Sat May 11 2024 - 03:31:42 EST

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Hello,

syzbot found the following issue on:

HEAD commit: ee5b455b0ada Merge tag 'slab-for-6.9-rc7-fixes' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=151c534b180000
kernel config: https://syzkaller.appspot.com/x/.config?x=7144b4fe7fbf5900
dashboard link: https://syzkaller.appspot.com/bug?extid=afcbef13b9fa6ae41f9a
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12618698980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=105fcb4b180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b58fa6d8c032/disk-ee5b455b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fe2cdcfb1b25/vmlinux-ee5b455b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9347ec3b62cf/bzImage-ee5b455b.xz

The issue was bisected to:

commit d15121be7485655129101f3960ae6add40204463
Author: Paolo Abeni <pabeni@xxxxxxxxxx>
Date: Mon May 8 06:17:44 2023 +0000

Revert "softirq: Let ksoftirqd do its job"

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1693d03f180000
final oops: https://syzkaller.appspot.com/x/report.txt?x=1593d03f180000
console output: https://syzkaller.appspot.com/x/log.txt?x=1193d03f180000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+afcbef13b9fa6ae41f9a@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: d15121be7485 ("Revert "softirq: Let ksoftirqd do its job"")

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5144
rcu: (detected by 1, t=10503 jiffies, g=11073, q=192 ncpus=2)
task:syz-executor172 state:R running task stack:27056 pid:5144 tgid:5144 ppid:5099 flags:0x00004002
Call Trace:
<IRQ>
sched_show_task kernel/sched/core.c:9192 [inline]
sched_show_task+0x42e/0x650 kernel/sched/core.c:9166
rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:262 [inline]
print_other_cpu_stall kernel/rcu/tree_stall.h:637 [inline]
check_cpu_stall kernel/rcu/tree_stall.h:796 [inline]
rcu_pending kernel/rcu/tree.c:3934 [inline]
rcu_sched_clock_irq+0x2613/0x3100 kernel/rcu/tree.c:2297
update_process_times+0x175/0x220 kernel/time/timer.c:2486
tick_sched_handle kernel/time/tick-sched.c:276 [inline]
tick_nohz_handler+0x376/0x530 kernel/time/tick-sched.c:297
__run_hrtimer kernel/time/hrtimer.c:1692 [inline]
__hrtimer_run_queues+0x657/0xcc0 kernel/time/hrtimer.c:1756
hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1818
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline]
__sysvec_apic_timer_interrupt+0x10f/0x450 arch/x86/kernel/apic/apic.c:1049
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x43/0xb0 arch/x86/kernel/apic/apic.c:1043
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 90 f3 0f 1e fa 53 48 8b 74 24 08 48 89 fb 48 83 c7 18 e8 6a 98 8c f6 48 89 df e8 c2 14 8d f6 e8 ed 98 b5 f6 fb bf 01 00 00 00 <e8> b2 4f 7e f6 65 8b 05 b3 88 24 75 85 c0 74 06 5b c3 cc cc cc cc
RSP: 0018:ffffc90000a08d18 EFLAGS: 00000202
RAX: 000000000184d5fe RBX: ffff8880b95401d0 RCX: 1ffffffff1f3e269
RDX: 0000000000000000 RSI: ffffffff8b0cae00 RDI: 0000000000000001
RBP: ffff8880b9540210 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8f9f55d7 R11: 0000000000000001 R12: dffffc0000000000
R13: 0000000000000001 R14: 0000000000000040 R15: ffff8880b95401b8
spin_unlock_irq include/linux/spinlock.h:401 [inline]
rps_unlock_irq_enable net/core/dev.c:229 [inline]
process_backlog+0x3e7/0x6f0 net/core/dev.c:6011
__napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:6638
napi_poll net/core/dev.c:6707 [inline]
net_rx_action+0x9ad/0xf10 net/core/dev.c:6822
handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
do_softirq kernel/softirq.c:455 [inline]
do_softirq+0xb2/0xf0 kernel/softirq.c:442
</IRQ>
<TASK>
__local_bh_enable_ip+0x100/0x120 kernel/softirq.c:382
local_bh_enable include/linux/bottom_half.h:33 [inline]
bpf_test_run+0x335/0x9e0 net/bpf/test_run.c:426
bpf_prog_test_run_skb+0xb17/0x1db0 net/bpf/test_run.c:1058
bpf_prog_test_run kernel/bpf/syscall.c:4269 [inline]
__sys_bpf+0xd56/0x4b40 kernel/bpf/syscall.c:5678
__do_sys_bpf kernel/bpf/syscall.c:5767 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5765 [inline]
__x64_sys_bpf+0x78/0xc0 kernel/bpf/syscall.c:5765
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2466eba819
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc5f447668 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f2466eba819
RDX: 0000000000000050 RSI: 0000000020000080 RDI: 000000000000000a
RBP: 0000000000000000 R08: 0000000100000000 R09: 0000000100000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
rcu: rcu_preempt kthread starved for 10546 jiffies! g11073 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:28736 pid:16 tgid:16 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5409 [inline]
__schedule+0xf15/0x5d00 kernel/sched/core.c:6746
__schedule_loop kernel/sched/core.c:6823 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6838
schedule_timeout+0x136/0x2a0 kernel/time/timer.c:2582
rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:1663
rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:1862
kthread+0x2c1/0x3a0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 5144 Comm: syz-executor172 Not tainted 6.9.0-rc7-syzkaller-00008-gee5b455b0ada #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 90 f3 0f 1e fa 53 48 8b 74 24 08 48 89 fb 48 83 c7 18 e8 6a 98 8c f6 48 89 df e8 c2 14 8d f6 e8 ed 98 b5 f6 fb bf 01 00 00 00 <e8> b2 4f 7e f6 65 8b 05 b3 88 24 75 85 c0 74 06 5b c3 cc cc cc cc
RSP: 0018:ffffc90000a08d18 EFLAGS: 00000202
RAX: 000000000184d5fe RBX: ffff8880b95401d0 RCX: 1ffffffff1f3e269
RDX: 0000000000000000 RSI: ffffffff8b0cae00 RDI: 0000000000000001
RBP: ffff8880b9540210 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8f9f55d7 R11: 0000000000000001 R12: dffffc0000000000
R13: 0000000000000001 R14: 0000000000000040 R15: ffff8880b95401b8
FS: 00005555756a8380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2466f370f0 CR3: 000000007c110000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
spin_unlock_irq include/linux/spinlock.h:401 [inline]
rps_unlock_irq_enable net/core/dev.c:229 [inline]
process_backlog+0x3e7/0x6f0 net/core/dev.c:6011
__napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:6638
napi_poll net/core/dev.c:6707 [inline]
net_rx_action+0x9ad/0xf10 net/core/dev.c:6822
handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
do_softirq kernel/softirq.c:455 [inline]
do_softirq+0xb2/0xf0 kernel/softirq.c:442
</IRQ>
<TASK>
__local_bh_enable_ip+0x100/0x120 kernel/softirq.c:382
local_bh_enable include/linux/bottom_half.h:33 [inline]
bpf_test_run+0x335/0x9e0 net/bpf/test_run.c:426
bpf_prog_test_run_skb+0xb17/0x1db0 net/bpf/test_run.c:1058
bpf_prog_test_run kernel/bpf/syscall.c:4269 [inline]
__sys_bpf+0xd56/0x4b40 kernel/bpf/syscall.c:5678
__do_sys_bpf kernel/bpf/syscall.c:5767 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5765 [inline]
__x64_sys_bpf+0x78/0xc0 kernel/bpf/syscall.c:5765
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2466eba819
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc5f447668 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f2466eba819
RDX: 0000000000000050 RSI: 0000000020000080 RDI: 000000000000000a
RBP: 0000000000000000 R08: 0000000100000000 R09: 0000000100000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
sched: RT throttling activated

---
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Next message: Zhaoyang Huang: "Re: [RFC PATCH 2/2] mm: introduce budgt control in readahead"
Previous message: Huang, Ying: "Re: [PATCH v10 00/12] LUF(Lazy Unmap Flush) reducing tlb numbers over 90%"
Next in thread: Hillf Danton: "Re: [syzbot] [bpf?] [net?] INFO: rcu detected stall in handle_softirqs"
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