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From: syzbot <syzbot+3aa9784721dfb90e984d@syzkaller.appspotmail.com>
To: gregkh@linuxfoundation.org, jslaby@suse.com,
	linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: KASAN: user-memory-access Write in n_tty_set_termios
Date: Sun, 01 Apr 2018 10:01:02 -0700	[thread overview]
Message-ID: <001a113ed31a122ced0568cc6be1@google.com> (raw)

Hello,

syzbot hit the following crash on upstream commit
10b84daddbec72c6b440216a69de9a9605127f7a (Sat Mar 31 17:59:00 2018 +0000)
Merge branch 'perf-urgent-for-linus' of  
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
syzbot dashboard link:  
https://syzkaller.appspot.com/bug?extid=3aa9784721dfb90e984d

So far this crash happened 2 times on upstream.
C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5259401455730688
syzkaller reproducer:  
https://syzkaller.appspot.com/x/repro.syz?id=5604984590696448
Raw console output:  
https://syzkaller.appspot.com/x/log.txt?id=6343571460325376
Kernel config:  
https://syzkaller.appspot.com/x/.config?id=-2760467897697295172
compiler: gcc (GCC) 7.1.1 20170620

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+3aa9784721dfb90e984d@syzkaller.appspotmail.com
It will help syzbot understand when the bug is fixed. See footer for  
details.
If you forward the report, please keep this part and the footer.

==================================================================
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:208  
[inline]
BUG: KASAN: user-memory-access in n_tty_set_termios+0xfc/0xcf0  
drivers/tty/n_tty.c:1766
Write of size 512 at addr 0000000000001060 by task syzkaller311122/4421

CPU: 0 PID: 4421 Comm: syzkaller311122 Not tainted 4.16.0-rc7+ #9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:17 [inline]
  dump_stack+0x194/0x24d lib/dump_stack.c:53
  kasan_report_error mm/kasan/report.c:352 [inline]
  kasan_report+0x140/0x360 mm/kasan/report.c:412
  check_memory_region_inline mm/kasan/kasan.c:260 [inline]
  check_memory_region+0x137/0x190 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:208 [inline]
  n_tty_set_termios+0xfc/0xcf0 drivers/tty/n_tty.c:1766
  tty_set_termios+0x750/0xa60 drivers/tty/tty_ioctl.c:341
  set_termios+0x392/0x6d0 drivers/tty/tty_ioctl.c:414
  tty_mode_ioctl+0x9fc/0xb30 drivers/tty/tty_ioctl.c:749
  n_tty_ioctl_helper+0x40/0x360 drivers/tty/tty_ioctl.c:940
  n_tty_ioctl+0x14d/0x2d0 drivers/tty/n_tty.c:2441
  tty_ioctl+0x336/0x1610 drivers/tty/tty_io.c:2655
  vfs_ioctl fs/ioctl.c:46 [inline]
  do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686
  SYSC_ioctl fs/ioctl.c:701 [inline]
  SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
  do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x445bf9
RSP: 002b:00007fdf68f52d18 EFLAGS: 00000297 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006dac24 RCX: 0000000000445bf9
RDX: 0000000020000040 RSI: 0000000000005402 RDI: 0000000000000021
RBP: 00000000006dac20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000297 R12: 6d74702f7665642f
R13: 00007ffdda32610f R14: 00007fdf68f539c0 R15: 0000000000000007
==================================================================
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 4421 Comm: syzkaller311122 Tainted: G    B             
4.16.0-rc7+ #9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:17 [inline]
  dump_stack+0x194/0x24d lib/dump_stack.c:53
  panic+0x1e4/0x41c kernel/panic.c:183
  kasan_end_report+0x50/0x50 mm/kasan/report.c:180
  kasan_report_error mm/kasan/report.c:359 [inline]
  kasan_report+0x149/0x360 mm/kasan/report.c:412
  check_memory_region_inline mm/kasan/kasan.c:260 [inline]
  check_memory_region+0x137/0x190 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:208 [inline]
  n_tty_set_termios+0xfc/0xcf0 drivers/tty/n_tty.c:1766
  tty_set_termios+0x750/0xa60 drivers/tty/tty_ioctl.c:341
  set_termios+0x392/0x6d0 drivers/tty/tty_ioctl.c:414
  tty_mode_ioctl+0x9fc/0xb30 drivers/tty/tty_ioctl.c:749
  n_tty_ioctl_helper+0x40/0x360 drivers/tty/tty_ioctl.c:940
  n_tty_ioctl+0x14d/0x2d0 drivers/tty/n_tty.c:2441
  tty_ioctl+0x336/0x1610 drivers/tty/tty_io.c:2655
  vfs_ioctl fs/ioctl.c:46 [inline]
  do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686
  SYSC_ioctl fs/ioctl.c:701 [inline]
  SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
  do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x445bf9
RSP: 002b:00007fdf68f52d18 EFLAGS: 00000297 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006dac24 RCX: 0000000000445bf9
RDX: 0000000020000040 RSI: 0000000000005402 RDI: 0000000000000021
RBP: 00000000006dac20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000297 R12: 6d74702f7665642f
R13: 00007ffdda32610f R14: 00007fdf68f539c0 R15: 0000000000000007
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This bug is generated by a dumb bot. It may contain errors.
See https://goo.gl/tpsmEJ for details.
Direct all questions to syzkaller@googlegroups.com.

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If you forgot to add the Reported-by tag, once the fix for this bug is  
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Note: if the crash happens again, it will cause creation of a new bug  
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             reply	other threads:[~2018-04-01 17:01 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-01 17:01 syzbot [this message]
2018-04-05 10:31 ` KASAN: user-memory-access Write in n_tty_set_termios Tetsuo Handa
2018-04-06 10:06   ` Tetsuo Handa
2018-07-17 10:14     ` [PATCH] n_tty: Protect tty->disc_data using refcount Tetsuo Handa
2018-07-24 15:22       ` [PATCH v2] " Tetsuo Handa
2018-07-25  8:06         ` Greg KH
2018-07-25 12:35           ` Tetsuo Handa
2018-08-29 13:53         ` Jiri Slaby
2018-08-29 14:48           ` Jiri Slaby
2018-08-29 15:02           ` Tetsuo Handa

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