syzbot


INFO: rcu detected stall in hci_cmd_timeout

Status: fixed on 2023/10/12 12:47
Subsystems: bluetooth
[Documentation on labels]
Fix commit: 8c21ab1bae94 net/sched: fq_pie: avoid stalls in fq_pie_timer()
First crash: 198d, last: 198d

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=0edc/1/0x4000000000000000 softirq=71289/71290 fqs=5109
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:        4          0            0
rcu: 	cputime:      145      52325           21   ==> 52480(ms)
rcu: 	(t=10500 jiffies g=103677 q=1300 ncpus=2)
CPU: 0 PID: 22222 Comm: kworker/u5:2 Not tainted 6.5.0-rc5-syzkaller-00056-gcacc6e22932f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Workqueue: hci9 hci_cmd_timeout
RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x0/0x20 kernel/kcov.c:289
Code: 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 8b 0c 24 48 89 f2 48 89 fe bf 06 00 00 00 e9 f8 fe ff ff 0f 1f 84 00 00 00 00 00 <f3> 0f 1e fa 48 8b 0c 24 40 0f b6 d6 40 0f b6 f7 bf 01 00 00 00 e9
RSP: 0018:ffffc90000007bb8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff88806f091170 RCX: 0000000000000100
RDX: ffff8880244e9dc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 000000006b62e798 R12: ffff88806f0911a8
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff486dbf18 CR3: 000000000c776000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 pie_calculate_probability+0x480/0x850 net/sched/sch_pie.c:415
 fq_pie_timer+0x1da/0x4f0 net/sched/sch_fq_pie.c:387
 call_timer_fn+0x1a0/0x580 kernel/time/timer.c:1700
 expire_timers kernel/time/timer.c:1751 [inline]
 __run_timers+0x764/0xb10 kernel/time/timer.c:2022
 run_timer_softirq+0x58/0xd0 kernel/time/timer.c:2035
 __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:console_flush_all+0x9b6/0xf50 kernel/printk/printk.c:2939
Code: d0 15 23 00 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 8e 66 1c 00 48 85 db 0f 85 94 03 00 00 e8 f0 6a 1c 00 fb 48 8b 44 24 08 <48> 8b 14 24 0f b6 00 83 e2 07 38 d0 7f 08 84 c0 0f 85 9d 04 00 00
RSP: 0018:ffffc9000460f8c8 EFLAGS: 00000293
RAX: fffff520008c1f44 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff8880244e9dc0 RSI: ffffffff81699db0 RDI: 0000000000000007
RBP: ffffffff8d4caba0 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 000000000000010d R12: 0000000000000000
R13: ffffffff8d4cabf8 R14: dffffc0000000000 R15: 0000000000000001
 console_unlock+0xc6/0x1f0 kernel/printk/printk.c:3007
 vprintk_emit+0x1c5/0x640 kernel/printk/printk.c:2307
 vprintk+0x89/0xa0 kernel/printk/printk_safe.c:50
 _printk+0xc8/0x100 kernel/printk/printk.c:2328
 bt_err+0xe5/0x120 net/bluetooth/lib.c:251
 hci_cmd_timeout+0x105/0x260 net/bluetooth/hci_core.c:1497
 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2600
 worker_thread+0x687/0x1110 kernel/workqueue.c:2751
 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>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/08/10 19:59 upstream cacc6e22932f 4df3089c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in hci_cmd_timeout
* Struck through repros no longer work on HEAD.