divide error in dummy_timer

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    22be26f7 usb-fuzzer: main usb gadget fuzzer driver
git tree:       https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=11e2fda7600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5fe29bc39eff9627
dashboard link: https://syzkaller.appspot.com/bug?extid=8ab8bf161038a8768553
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14f664e4e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14674000e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+8ab8bf161038a8768553@xxxxxxxxxxxxxxxxxxxxxxxxx

divide error: 0000 [#1] SMP KASAN
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:transfer drivers/usb/gadget/udc/dummy_hcd.c:1426 [inline]
RIP: 0010:dummy_timer+0xad5/0x2fa2 drivers/usb/gadget/udc/dummy_hcd.c:1950
Code: 0f 84 f5 fd ff ff e8 8a 55 ab fd 89 de 44 89 e7 e8 70 56 ab fd 41 39  
dc 0f 82 b0 08 00 00 e8 72 55 ab fd 44 89 e0 31 d2 31 ff <f7> f3 89 d6 89  
94 24 c0 00 00 00 e8 cb 56 ab fd 8b 94 24 c0 00 00
RSP: 0018:ffff8881db209b20 EFLAGS: 00010046
RAX: 0000000000000040 RBX: 0000000000000000 RCX: ffffffff8392c330
RDX: 0000000000000000 RSI: ffffffff8392c33e RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff86c2b200 R09: ffffed103b641353
R10: ffffed103b641352 R11: 0000000000000003 R12: 0000000000000040
R13: ffff8881d58c0000 R14: dffffc0000000000 R15: ffff8881d78d5a00
FS:  0000000000000000(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb771a61000 CR3: 00000001d2295000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 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:default_idle+0x28/0x2e0 arch/x86/kernel/process.c:581
Code: 90 90 41 56 41 55 65 44 8b 2d f4 00 92 7a 41 54 55 53 0f 1f 44 00 00  
e8 c6 b2 d3 fb e9 07 00 00 00 0f 00 2d ea a5 52 00 fb f4 <65> 44 8b 2d d0  
00 92 7a 0f 1f 44 00 00 5b 5d 41 5c 41 5d 41 5e c3
RSP: 0018:ffffffff86c07da8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000007 RBX: ffffffff86c2b200 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000006 RDI: ffffffff86c2ba4c
RBP: fffffbfff0d85640 R08: ffffffff86c2b200 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 cpuidle_idle_call kernel/sched/idle.c:154 [inline]
 do_idle+0x3b6/0x500 kernel/sched/idle.c:263
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:355
 start_kernel+0x82a/0x864 init/main.c:784
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241
Modules linked in:
---[ end trace 02e2d9c7c53d85a5 ]---
RIP: 0010:transfer drivers/usb/gadget/udc/dummy_hcd.c:1426 [inline]
RIP: 0010:dummy_timer+0xad5/0x2fa2 drivers/usb/gadget/udc/dummy_hcd.c:1950
Code: 0f 84 f5 fd ff ff e8 8a 55 ab fd 89 de 44 89 e7 e8 70 56 ab fd 41 39  
dc 0f 82 b0 08 00 00 e8 72 55 ab fd 44 89 e0 31 d2 31 ff <f7> f3 89 d6 89  
94 24 c0 00 00 00 e8 cb 56 ab fd 8b 94 24 c0 00 00
RSP: 0018:ffff8881db209b20 EFLAGS: 00010046
RAX: 0000000000000040 RBX: 0000000000000000 RCX: ffffffff8392c330
RDX: 0000000000000000 RSI: ffffffff8392c33e RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff86c2b200 R09: ffffed103b641353
R10: ffffed103b641352 R11: 0000000000000003 R12: 0000000000000040
R13: ffff8881d58c0000 R14: dffffc0000000000 R15: ffff8881d78d5a00
FS:  0000000000000000(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb771a61000 CR3: 00000001d2295000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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