Hello,
syzbot has tested the proposed patch but the reproducer still triggered
crash:
INFO: rcu detected stall in dummy_timer
radio-si470x 5-1:0.0: non-zero urb status (-71)
radio-si470x 3-1:0.0: non-zero urb status (-71)
rcu: INFO: rcu_sched self-detected stall on CPU
rcu: 1-....: (8213 ticks this GP) idle=4f6/1/0x4000000000000004
softirq=3368/3368 fqs=3
(t=10501 jiffies g=2713 q=134)
NMI backtrace for cpu 1
CPU: 1 PID: 1853 Comm: syz-executor.2 Not tainted 5.4.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
nmi_cpu_backtrace.cold+0x55/0x96 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1b0/0x1c7 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
rcu_dump_cpu_stacks+0x169/0x1b3 kernel/rcu/tree_stall.h:254
print_cpu_stall kernel/rcu/tree_stall.h:455 [inline]
check_cpu_stall kernel/rcu/tree_stall.h:529 [inline]
rcu_pending kernel/rcu/tree.c:2795 [inline]
rcu_sched_clock_irq.cold+0x4da/0x936 kernel/rcu/tree.c:2244
update_process_times+0x25/0x60 kernel/time/timer.c:1726
tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:167
tick_sched_timer+0x42/0x130 kernel/time/tick-sched.c:1299
__run_hrtimer kernel/time/hrtimer.c:1514 [inline]
__hrtimer_run_queues+0x303/0xc60 kernel/time/hrtimer.c:1576
hrtimer_interrupt+0x2e8/0x730 kernel/time/hrtimer.c:1638
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
smp_apic_timer_interrupt+0xf5/0x500 arch/x86/kernel/apic/apic.c:1135
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:85 [inline]
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160
[inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x40/0x50
kernel/locking/spinlock.c:191
Code: e8 95 14 b3 fb 48 89 ef e8 6d f3 b3 fb f6 c7 02 75 11 53 9d e8 61 ba
d0 fb 65 ff 0d a2 67 8f 7a 5b 5d c3 e8 02 be d0 fb 53 9d <eb> ed 0f 1f 40
00 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 fd 65 ff
RSP: 0018:ffff8881db309b08 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000007 RBX: 0000000000000206 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8881ce7fb84c
RBP: ffff8881d50f0000 R08: ffff8881ce7fb000 R09: fffffbfff11b23b8
R10: fffffbfff11b23b7 R11: ffffffff88d91dbf R12: 0000000000000080
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8881c6617500
spin_unlock_irqrestore include/linux/spinlock.h:393 [inline]
dummy_timer+0x131b/0x2fa2 drivers/usb/gadget/udc/dummy_hcd.c:1980
call_timer_fn+0x179/0x650 kernel/time/timer.c:1404
expire_timers kernel/time/timer.c:1449 [inline]
__run_timers kernel/time/timer.c:1773 [inline]
__run_timers kernel/time/timer.c:1740 [inline]
run_timer_softirq+0x5e3/0x1490 kernel/time/timer.c:1786
__do_softirq+0x221/0x912 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x178/0x1a0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0x12f/0x500 arch/x86/kernel/apic/apic.c:1137
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
</IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:85 [inline]
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160
[inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x40/0x50
kernel/locking/spinlock.c:191
Code: e8 95 14 b3 fb 48 89 ef e8 6d f3 b3 fb f6 c7 02 75 11 53 9d e8 61 ba
d0 fb 65 ff 0d a2 67 8f 7a 5b 5d c3 e8 02 be d0 fb 53 9d <eb> ed 0f 1f 40
00 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 fd 65 ff
RSP: 0018:ffff8881cd477ba8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000007 RBX: 0000000000000246 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000006 RDI: ffff8881ce7fb84c
RBP: ffff8881db325b00 R08: ffff8881ce7fb000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff8881db325b80 R14: 0000000000000000 R15: ffff8881db325b00
unlock_hrtimer_base kernel/time/hrtimer.c:898 [inline]
hrtimer_start_range_ns+0x5bf/0xb00 kernel/time/hrtimer.c:1133
hrtimer_start_expires include/linux/hrtimer.h:435 [inline]
hrtimer_sleeper_start_expires kernel/time/hrtimer.c:1792 [inline]
do_nanosleep+0x1b9/0x650 kernel/time/hrtimer.c:1868
hrtimer_nanosleep+0x249/0x4f0 kernel/time/hrtimer.c:1924
__do_sys_nanosleep kernel/time/hrtimer.c:1958 [inline]
__se_sys_nanosleep kernel/time/hrtimer.c:1945 [inline]
__x64_sys_nanosleep+0x19d/0x220 kernel/time/hrtimer.c:1945
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457f00
Code: c0 5b 5d c3 66 0f 1f 44 00 00 8b 04 24 48 83 c4 18 5b 5d c3 66 0f 1f
44 00 00 83 3d 51 e8 61 00 00 75 14 b8 23 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 0f 83 24 d3 fb ff c3 48 83 ec 08 e8 ea 46 00 00
RSP: 002b:00007ffe6aaf7d48 EFLAGS: 00000246 ORIG_RAX: 0000000000000023
RAX: ffffffffffffffda RBX: 000000000000961f RCX: 0000000000457f00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffe6aaf7d50
RBP: 0000000000000004 R08: 0000000000000001 R09: 0000000002432940
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007ffe6aaf7da0 R14: 0000000000008efa R15: 00007ffe6aaf7db0
radio-si470x 1-1:0.0: non-zero urb status (-71)
radio-si470x 5-1:0.0: non-zero urb status (-71)
radio-si470x 3-1:0.0: non-zero urb status (-71)
radio-si470x 4-1:0.0: non-zero urb status (-71)
radio-si470x 1-1:0.0: non-zero urb status (-71)
radio-si470x 2-1:0.0: non-zero urb status (-71)
radio-si470x 6-1:0.0: non-zero urb status (-71)
radio-si470x 6-1:0.0: non-zero urb status (-71)
radio-si470x 2-1:0.0: non-zero urb status (-71)
Tested on:
commit: 22be26f7 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=177ca17ae00000
kernel config: https://syzkaller.appspot.com/x/.config?x=387eccb7ac68ec5
dashboard link: https://syzkaller.appspot.com/bug?extid=9ca7a12fd736d93e0232
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=1226e536e00000
