RSP: 002b:00007f415cf45c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f415cf45c90 RCX: 0000000000458d99
RDX: 0000000020000140 RSI: 0000000000005423 RDI: 0000000000000004
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f415cf466d4
R13: 00000000004c31f5 R14: 00000000004d6588 R15: 0000000000000005
BUG: unable to handle page fault for address = fffffffffffffff4
#PF: supervisor-privileged read access from kernel code
#PF: error_code(0x0000) - not-present page
PGD 8870067 P4D 8870067 PUD 8872067 PMD 0 
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 18296 Comm: syz-executor.2 Not tainted 5.1.0-rc6-next-20190424 #30
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:slhc_free+0x31/0xb0 drivers/net/slip/slhc.c:159
Code: 54 49 89 fc e8 c0 b3 15 fd 4d 85 e4 74 77 e8 b6 b3 15 fd 4c 89 e2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 75 6d <4d> 8b 2c 24 4d 85 ed 74 0d e8 91 b3 15 fd 4c 89 ef e8 09 5b 4e fd
RSP: 0018:ffff88805c0ef9f0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: fffffffffffffff4 RCX: ffffc9000a225000
RDX: 1ffffffffffffffe RSI: ffffffff845b7bea RDI: fffffffffffffff4
RBP: ffff88805c0efa00 R08: ffff888059ea6140 R09: ffff888059ea6a30
R10: 0000000000000000 R11: 0000000000000000 R12: fffffffffffffff4
R13: ffff88808756ec80 R14: 00000000ffffff97 R15: ffff888065cf9280
FS:  00007f415cf46700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffff4 CR3: 00000000864ea000 CR4: 00000000001406f0
Call Trace:
 sl_alloc_bufs drivers/net/slip/slip.c:196 [inline]
 slip_open+0xe16/0x1138 drivers/net/slip/slip.c:821
 tty_ldisc_open.isra.0+0x8b/0xe0 drivers/tty/tty_ldisc.c:469
 tty_set_ldisc+0x2d7/0x690 drivers/tty/tty_ldisc.c:596
 tiocsetd drivers/tty/tty_io.c:2332 [inline]
 tty_ioctl+0x5dc/0x15c0 drivers/tty/tty_io.c:2592
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0x103/0x670 arch/x86/entry/common.c:298
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458d99
Code: ad b8 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f415cf45c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f415cf45c90 RCX: 0000000000458d99
RDX: 0000000020000140 RSI: 0000000000005423 RDI: 0000000000000004
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f415cf466d4
R13: 00000000004c31f5 R14: 00000000004d6588 R15: 0000000000000005
Modules linked in:
CR2: fffffffffffffff4
---[ end trace 59e68c15936d56e7 ]---
RIP: 0010:slhc_free+0x31/0xb0 drivers/net/slip/slhc.c:159
Code: 54 49 89 fc e8 c0 b3 15 fd 4d 85 e4 74 77 e8 b6 b3 15 fd 4c 89 e2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 75 6d <4d> 8b 2c 24 4d 85 ed 74 0d e8 91 b3 15 fd 4c 89 ef e8 09 5b 4e fd
RSP: 0018:ffff88805c0ef9f0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: fffffffffffffff4 RCX: ffffc9000a225000
RDX: 1ffffffffffffffe RSI: ffffffff845b7bea RDI: fffffffffffffff4
RBP: ffff88805c0efa00 R08: ffff888059ea6140 R09: ffff888059ea6a30
R10: 0000000000000000 R11: 0000000000000000 R12: fffffffffffffff4
R13: ffff88808756ec80 R14: 00000000ffffff97 R15: ffff888065cf9280
FS:  00007f415cf46700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffff4 CR3: 00000000864ea000 CR4: 00000000001406f0