pts pts0: tty_release: tty->count(3) != (#fd's(2) + #kopen's(0))
isofs_fill_super: bread failed, dev=loop7, iso_blknum=36, block=72
==================================================================
BUG: KASAN: user-memory-access in memset include/linux/string.h:330 [inline]
BUG: KASAN: user-memory-access in bitmap_zero include/linux/bitmap.h:216 [inline]
BUG: KASAN: user-memory-access in n_tty_set_termios+0x106/0xe80 drivers/tty/n_tty.c:1784
Write of size 512 at addr 0000000000001060 by task syz-executor3/25874

CPU: 1 PID: 25874 Comm: syz-executor3 Not tainted 4.19.0-rc2-next-20180904+ #55
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+0x1c9/0x2b4 lib/dump_stack.c:113
 kasan_report_error mm/kasan/report.c:352 [inline]
 kasan_report.cold.7+0x6d/0x30d mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 memset+0x23/0x40 mm/kasan/kasan.c:285
 memset include/linux/string.h:330 [inline]
 bitmap_zero include/linux/bitmap.h:216 [inline]
 n_tty_set_termios+0x106/0xe80 drivers/tty/n_tty.c:1784
 tty_set_termios+0x7a0/0xac0 drivers/tty/tty_ioctl.c:341
 set_termios+0x41e/0x7d0 drivers/tty/tty_ioctl.c:414
 tty_mode_ioctl+0x855/0xb50 drivers/tty/tty_ioctl.c:749
 n_tty_ioctl_helper+0x54/0x3b0 drivers/tty/tty_ioctl.c:940
 n_tty_ioctl+0x54/0x360 drivers/tty/n_tty.c:2450
 tty_ioctl+0x5e1/0x1870 drivers/tty/tty_io.c:2655
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl fs/ioctl.c:707 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457099
Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f15f6c18c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f15f6c196d4 RCX: 0000000000457099
RDX: 00000000200000c0 RSI: 0000000000005402 RDI: 0000000000000005
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004d0de0 R14: 00000000004c6729 R15: 0000000000000000
==================================================================