kernel BUG at drivers/tty/tty

kernel BUG at drivers/tty/tty_ldisc.c:LINE!
Status: fixed on 2018/05/08 18:30
Reported-by: syzbot+40b7287c2dc987c48c81@syzkaller.appspotmail.com
Fix commit: 598c2d41 tty: Avoid possible error pointer dereference at tty_ldisc_restore(). bcdd0ca8 tty: Use __GFP_NOFAIL for tty_ldisc_get()
First crash: 825d, last: 807d

Sample crash report:

------------[ cut here ]------------
kernel BUG at drivers/tty/tty_ldisc.c:684!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 9546 Comm: syz-executor2 Not tainted 4.17.0-rc1+ #6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:tty_ldisc_reinit+0x26f/0x2e0 drivers/tty/tty_ldisc.c:684
RSP: 0018:ffff88018cd9f588 EFLAGS: 00010246
RAX: 0000000000040000 RBX: ffff8801cefd4180 RCX: ffffc900046dc000
RDX: 0000000000040000 RSI: ffffffff8381083f RDI: 0000000000000005
RBP: ffff88018cd9f5b0 R08: ffff8801ab978100 R09: 0000000000000006
R10: ffff8801ab978100 R11: 0000000000000000 R12: fffffffffffffff4
R13: 0000000000000000 R14: ffff8801cefd45e0 R15: dffffc0000000000
FS:  00007fa81910b700(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004d9204 CR3: 00000001b97b1000 CR4: 00000000001406f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 tty_reopen+0x1e4/0x250 drivers/tty/tty_io.c:1272
 tty_open_by_driver drivers/tty/tty_io.c:1953 [inline]
 tty_open+0x7f5/0xb10 drivers/tty/tty_io.c:2007
 chrdev_open+0x256/0x760 fs/char_dev.c:417
 do_dentry_open+0x7ef/0xf10 fs/open.c:784
 vfs_open+0x139/0x230 fs/open.c:906
 do_last fs/namei.c:3365 [inline]
 path_openat+0x1676/0x4e20 fs/namei.c:3501
 do_filp_open+0x249/0x350 fs/namei.c:3535
 do_sys_open+0x56f/0x740 fs/open.c:1093
 __do_sys_open fs/open.c:1111 [inline]
 __se_sys_open fs/open.c:1106 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1106
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x40f581
RSP: 002b:00007fa81910abb0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000040f581
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007fa81910abd0
RBP: 000000000072bea0 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000064 R11: 0000000000000293 R12: 0000000000000015
R13: 0000000000000698 R14: 00000000006fcee0 R15: 0000000000000004
Code: 83 b0 00 00 00 00 00 00 00 e9 f4 fd ff ff e8 69 27 f8 fd 31 ff 44 89 ee e8 6f 28 f8 fd 45 85 ed 0f 85 d7 fd ff ff e8 51 27 f8 fd <0f> 0b 4c 89 f7 e8 67 6e 34 fe e9 31 fe ff ff e8 9d 6e 34 fe e9 
RIP: tty_ldisc_reinit+0x26f/0x2e0 drivers/tty/tty_ldisc.c:684 RSP: ffff88018cd9f588
---[ end trace 91ca20c2823f5eb2 ]---

Crashes (6):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Maintainers
ci-upstream-kasan-gce-root	2018/04/17 01:32	upstream	a27fc142	b80fd3b5	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci-upstream-kasan-gce-root	2018/04/16 13:03	upstream	60cc43fc	802ac912	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci-upstream-kasan-gce-root	2018/04/09 20:46	upstream	fd40ffc7	b9f65507	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci-upstream-kasan-gce-root	2018/04/03 00:11	upstream	86bbbeba	676bd07e	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci-upstream-kasan-gce-root	2018/03/30 16:47	upstream	c2a98384	d47f0ed6	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci-upstream-kasan-gce-root	2018/03/30 13:41	upstream	c2a98384	d47f0ed6	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org