Message-ID: <000000000000438c4a06031aff8b@google.com>
Date:   Thu, 17 Aug 2023 02:25:46 -0700
From:   syzbot <syzbot+77195ae75047f1438785@...kaller.appspotmail.com>
To:     linux-kernel@...r.kernel.org, peterz@...radead.org,
        syzkaller-bugs@...glegroups.com, tglx@...utronix.de
Subject: [syzbot] [kernel?] INFO: rcu detected stall in schedule (6)

Hello,

syzbot found the following issue on:

HEAD commit:    a785fd28d31f Merge tag 'for-6.5-rc5-tag' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=167d8e17a80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3e670757e16affb
dashboard link: https://syzkaller.appspot.com/bug?extid=77195ae75047f1438785
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=15ec36ada80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f025e375131a/disk-a785fd28.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d38bc269b3fb/vmlinux-a785fd28.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5eb32eee65b8/bzImage-a785fd28.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+77195ae75047f1438785@...kaller.appspotmail.com

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=816c/1/0x4000000000000000 softirq=8838/8840 fqs=5242
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:        0          0            0
rcu: 	cputime:    29521      22957            0   ==> 52480(ms)
rcu: 	(t=10500 jiffies g=5877 q=1892 ncpus=2)
CPU: 0 PID: 15 Comm: ksoftirqd/0 Not tainted 6.5.0-rc5-syzkaller-00362-ga785fd28d31f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:write_comp_data+0x7/0x90 kernel/kcov.c:230
Code: 81 e2 00 01 ff 00 75 10 65 48 8b 04 25 80 b9 03 00 48 8b 80 f8 15 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 65 8b 05 c1 b6 7d 7e <49> 89 f1 89 c6 49 89 d2 81 e6 00 01 00 00 49 89 f8 65 48 8b 14 25
RSP: 0018:ffffc90000007d58 EFLAGS: 00000293
RAX: 0000000000000102 RBX: ffff8880638b6394 RCX: ffffffff88595887
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000004
RBP: 0000000000000008 R08: 0000000000000004 R09: 0000000000000008
R10: 0000000000000010 R11: 0000000000000000 R12: 0000000000000010
R13: ffff88807ce5ab60 R14: 0000000000000000 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000600 CR3: 000000000c776000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 taprio_dequeue_tc_priority+0x247/0x4b0 net/sched/sch_taprio.c:808
 taprio_dequeue+0x12e/0x5f0 net/sched/sch_taprio.c:868
 dequeue_skb net/sched/sch_generic.c:292 [inline]
 qdisc_restart net/sched/sch_generic.c:397 [inline]
 __qdisc_run+0x1c4/0x19d0 net/sched/sch_generic.c:415
 qdisc_run include/net/pkt_sched.h:125 [inline]
 qdisc_run include/net/pkt_sched.h:122 [inline]
 net_tx_action+0x71e/0xc80 net/core/dev.c:5049
 __do_softirq+0x218/0x965 kernel/softirq.c:553
 invoke_softirq kernel/softirq.c:427 [inline]
 __irq_exit_rcu kernel/softirq.c:632 [inline]
 irq_exit_rcu+0xb7/0x120 kernel/softirq.c:644
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1109
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:finish_task_switch.isra.0+0x220/0xc90 kernel/sched/core.c:5253
Code: 0a 00 00 44 8b 0d c0 01 52 0d 45 85 c9 0f 85 c0 01 00 00 48 89 df e8 ff f8 ff ff e8 9a dd 32 00 fb 65 48 8b 1c 25 80 b9 03 00 <48> 8d bb e0 15 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1
RSP: 0018:ffffc90000147c88 EFLAGS: 00000202
RAX: 000000000006247f RBX: ffff888015e5bb80 RCX: 1ffffffff1d56e19
RDX: 0000000000000000 RSI: ffffffff8a6c80a0 RDI: ffffffff8ac811c0
RBP: ffffc90000147cd0 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8eaba257 R11: 0000000000000000 R12: ffff8880b983d118
R13: ffff88802bd49dc0 R14: 0000000000000000 R15: ffff8880b983c3c0
 context_switch kernel/sched/core.c:5384 [inline]
 __schedule+0xee9/0x59f0 kernel/sched/core.c:6710
 schedule+0xe7/0x1b0 kernel/sched/core.c:6786
 smpboot_thread_fn+0x2ee/0xa00 kernel/smpboot.c:160
 kthread+0x33a/0x430 kernel/kthread.c:389
 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>


---
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