BUG: unable to handle page fault for address = ADDR

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    c392798a Add linux-next specific files for 20190424
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14772c42a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=37a4076eb047eef5
dashboard link: https://syzkaller.appspot.com/bug?extid=45474c076a4927533d2e
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1369c242a00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12ee2e88a00000

The bug was bisected to:

commit bcdd0ca8cb8730573afebcaae4138f8f4c8eaa20
Author: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Date:   Wed Apr 25 11:12:31 2018 +0000

    tty: Use __GFP_NOFAIL for tty_ldisc_get()

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=157d9014a00000
final crash:    https://syzkaller.appspot.com/x/report.txt?x=177d9014a00000
console output: https://syzkaller.appspot.com/x/log.txt?x=137d9014a00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+45474c076a4927533d2e@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: bcdd0ca8cb87 ("tty: Use __GFP_NOFAIL for tty_ldisc_get()")

 do_syscall_64+0x103/0x670 arch/x86/entry/common.c:298
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441149
Code: e8 5c ae 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 bb 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffd8ae1c38 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441149
RDX: 0000000020000140 RSI: 0000000000005423 RDI: 0000000000000003
RBP: 00007fffd8ae1c50 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
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: 1 PID: 7949 Comm: syz-executor714 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:ffff8880a3e7f9f0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: fffffffffffffff4 RCX: 1ffff1101426e1c6
RDX: 1ffffffffffffffe RSI: ffffffff845b7bea RDI: fffffffffffffff4
RBP: ffff8880a3e7fa00 R08: ffff8880a1370540 R09: ffff8880a1370e30
R10: 0000000000000000 R11: 0000000000000000 R12: fffffffffffffff4
R13: ffff88809f531040 R14: 00000000ffffff97 R15: ffff8880a3dff2c0
FS:  0000555556f4d880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffff4 CR3: 000000008b56d000 CR4: 00000000001406e0
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: 0033:0x441149
Code: e8 5c ae 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 bb 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffd8ae1c38 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441149
RDX: 0000000020000140 RSI: 0000000000005423 RDI: 0000000000000003
RBP: 00007fffd8ae1c50 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
CR2: fffffffffffffff4
---[ end trace c314d2d667c67584 ]---
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:ffff8880a3e7f9f0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: fffffffffffffff4 RCX: 1ffff1101426e1c6
RDX: 1ffffffffffffffe RSI: ffffffff845b7bea RDI: fffffffffffffff4
RBP: ffff8880a3e7fa00 R08: ffff8880a1370540 R09: ffff8880a1370e30
R10: 0000000000000000 R11: 0000000000000000 R12: fffffffffffffff4
R13: ffff88809f531040 R14: 00000000ffffff97 R15: ffff8880a3dff2c0
FS:  0000555556f4d880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffff4 CR3: 000000008b56d000 CR4: 00000000001406e0


---
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