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SubjectKASAN: use-after-free Read in hfa384x_usbin_callback

syzbot found the following crash on:

HEAD commit: e17994d1 usb: core: kcov: collect coverage from usb comple..
git tree: usb-fuzzer
console output:
kernel config:
dashboard link:
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:
C reproducer:

IMPORTANT: if you fix the bug, please add the following tag to the commit:

BUG: KASAN: use-after-free in memcpy include/linux/string.h:381 [inline]
BUG: KASAN: use-after-free in skb_put_data include/linux/skbuff.h:2284 [inline]
BUG: KASAN: use-after-free in hfa384x_int_rxmonitor drivers/staging/wlan-ng/hfa384x_usb.c:3412 [inline]
BUG: KASAN: use-after-free in hfa384x_usbin_rx drivers/staging/wlan-ng/hfa384x_usb.c:3312 [inline]
BUG: KASAN: use-after-free in hfa384x_usbin_callback+0x1993/0x2360 drivers/staging/wlan-ng/hfa384x_usb.c:3026
Read of size 34945 at addr ffff8881cda9f33c by task swapper/0/0

CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.6.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xef/0x16e lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xd3/0x314 mm/kasan/report.c:374
__kasan_report.cold+0x37/0x77 mm/kasan/report.c:506
kasan_report+0xe/0x20 mm/kasan/common.c:641
check_memory_region_inline mm/kasan/generic.c:185 [inline]
check_memory_region+0x152/0x1c0 mm/kasan/generic.c:192
memcpy+0x20/0x50 mm/kasan/common.c:127
memcpy include/linux/string.h:381 [inline]
skb_put_data include/linux/skbuff.h:2284 [inline]
hfa384x_int_rxmonitor drivers/staging/wlan-ng/hfa384x_usb.c:3412 [inline]
hfa384x_usbin_rx drivers/staging/wlan-ng/hfa384x_usb.c:3312 [inline]
hfa384x_usbin_callback+0x1993/0x2360 drivers/staging/wlan-ng/hfa384x_usb.c:3026
__usb_hcd_giveback_urb+0x29a/0x550 drivers/usb/core/hcd.c:1650
usb_hcd_giveback_urb+0x368/0x420 drivers/usb/core/hcd.c:1716
dummy_timer+0x1258/0x32ae drivers/usb/gadget/udc/dummy_hcd.c:1966
call_timer_fn+0x195/0x6f0 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+0x5f9/0x1500 kernel/time/timer.c:1786
__do_softirq+0x21e/0x950 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:546 [inline]
smp_apic_timer_interrupt+0x141/0x540 arch/x86/kernel/apic/apic.c:1146
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
RIP: 0010:default_idle+0x28/0x300 arch/x86/kernel/process.c:696
Code: cc cc 41 56 41 55 65 44 8b 2d 44 77 72 7a 41 54 55 53 0f 1f 44 00 00 e8 b6 62 b5 fb e9 07 00 00 00 0f 00 2d ea 0c 53 00 fb f4 <65> 44 8b 2d 20 77 72 7a 0f 1f 44 00 00 5b 5d 41 5c 41 5d 41 5e c3
RSP: 0018:ffffffff87007d80 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000007 RBX: ffffffff8702cc40 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000006 RDI: ffffffff8702d48c
RBP: fffffbfff0e05988 R08: ffffffff8702cc40 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff87e607c0 R15: 0000000000000000
cpuidle_idle_call kernel/sched/idle.c:154 [inline]
do_idle+0x3e0/0x500 kernel/sched/idle.c:269
cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:361
start_kernel+0xe16/0xe5a init/main.c:998
secondary_startup_64+0xb6/0xc0 arch/x86/kernel/head_64.S:242

The buggy address belongs to the page:
page:ffffea000736a600 refcount:32769 mapcount:0 mapping:0000000000000000 index:0x0 compound_mapcount: 0
flags: 0x200000000010000(head)
raw: 0200000000010000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00008001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881cda9ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8881cda9ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881cdaa0000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881cdaa0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881cdaa0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

This bug is generated by a bot. It may contain errors.
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