KASAN: user-memory-access Read in filp_close

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: b791d1bd Merge tag 'locking-kcsan-2020-06-11' of git://git..
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=10a4cf46100000
kernel config: https://syzkaller.appspot.com/x/.config?x=16c2467d4b6dbee2
dashboard link: https://syzkaller.appspot.com/bug?extid=b9ce45b2a2e1814154cf
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
CC: [linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+b9ce45...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: user-memory-access in instrument_atomic_read include/linux/instrumented.h:56 [inline]
BUG: KASAN: user-memory-access in atomic64_read include/asm-generic/atomic-instrumented.h:837 [inline]
BUG: KASAN: user-memory-access in atomic_long_read include/asm-generic/atomic-long.h:29 [inline]
BUG: KASAN: user-memory-access in filp_close+0x22/0x170 fs/open.c:1276
Read of size 8 at addr 0000000100000078 by task syz-executor.4/4734

CPU: 1 PID: 4734 Comm: syz-executor.4 Not tainted 5.7.0-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+0xf6/0x16e lib/dump_stack.c:118
__kasan_report mm/kasan/report.c:517 [inline]
kasan_report.cold+0x6a/0x7c mm/kasan/report.c:530
check_memory_region_inline mm/kasan/generic.c:186 [inline]
check_memory_region+0x173/0x1d0 mm/kasan/generic.c:192
instrument_atomic_read include/linux/instrumented.h:56 [inline]
atomic64_read include/asm-generic/atomic-instrumented.h:837 [inline]
atomic_long_read include/asm-generic/atomic-long.h:29 [inline]
filp_close+0x22/0x170 fs/open.c:1276
__close_fd+0x133/0x200 fs/file.c:641
__do_sys_close fs/open.c:1301 [inline]
__se_sys_close fs/open.c:1299 [inline]
__x64_sys_close+0x69/0x100 fs/open.c:1299
do_syscall_64+0xb6/0x5a0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x416661
Code: Bad RIP value.
RSP: 002b:00007fffd0a28390 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 0000000000416661
RDX: 0000000000000000 RSI: 000000000000174a RDI: 0000000000000007
RBP: 0000000000000001 R08: 00000000accc774a R09: 00000000accc774e
R10: 00007fffd0a28480 R11: 0000000000000293 R12: 000000000078c900
R13: 000000000078c900 R14: ffffffffffffffff R15: 000000000078bfac
==================================================================


---
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[Andrey Konovalov]

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Some weird one-off report, unlikely actionable.

#syz invalid