general protection fault in __io_uring_register

From: syzbot
Date: Fri Dec 27 2019 - 02:13:19 EST


Hello,

syzbot found the following crash on:

HEAD commit: 7ddd09fc Add linux-next specific files for 20191220
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1295eec1e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=f183b01c3088afc6
dashboard link: https://syzkaller.appspot.com/bug?extid=6b340e00888c8016e91d
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+6b340e00888c8016e91d@xxxxxxxxxxxxxxxxxxxxxxxxx

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 21080 Comm: syz-executor.2 Not tainted 5.5.0-rc2-next-20191220-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:io_sqe_files_register fs/io_uring.c:4941 [inline]
RIP: 0010:__io_uring_register+0x555/0x2790 fs/io_uring.c:6121
Code: 3c 02 00 0f 85 7e 20 00 00 49 8b 9f 68 01 00 00 e8 e0 90 9d ff 48 8d 7b 48 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 49 20 00 00 48 8b 95 20 ff ff ff 48 c7 43 48 00
RSP: 0018:ffffc9000491fd10 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc9000e02f000
RDX: 0000000000000009 RSI: ffffffff81d7c4b0 RDI: 0000000000000048
RBP: ffffc9000491fea8 R08: 1ffffffff165b7dd R09: fffffbfff165b7de
R10: fffffbfff165b7dd R11: ffffffff8b2dbeef R12: ffff88809457a600
R13: 0000000000000002 R14: 000000000000035b R15: ffff8880a76c5800
FS: 00007f6f11615700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff73a203db8 CR3: 000000009ae2a000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__do_sys_io_uring_register fs/io_uring.c:6177 [inline]
__se_sys_io_uring_register fs/io_uring.c:6159 [inline]
__x64_sys_io_uring_register+0x1a1/0x570 fs/io_uring.c:6159
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a919
Code: ad b6 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 b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f6f11614c78 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045a919
RDX: 0000000020000280 RSI: 0000000000000002 RDI: 0000000000000004
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000035b R11: 0000000000000246 R12: 00007f6f116156d4
R13: 00000000004cf810 R14: 00000000004d70a0 R15: 00000000ffffffff
Modules linked in:
---[ end trace 128a762a80939ab8 ]---
RIP: 0010:io_sqe_files_register fs/io_uring.c:4941 [inline]
RIP: 0010:__io_uring_register+0x555/0x2790 fs/io_uring.c:6121
Code: 3c 02 00 0f 85 7e 20 00 00 49 8b 9f 68 01 00 00 e8 e0 90 9d ff 48 8d 7b 48 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 49 20 00 00 48 8b 95 20 ff ff ff 48 c7 43 48 00
RSP: 0018:ffffc9000491fd10 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc9000e02f000
RDX: 0000000000000009 RSI: ffffffff81d7c4b0 RDI: 0000000000000048
RBP: ffffc9000491fea8 R08: 1ffffffff165b7dd R09: fffffbfff165b7de
R10: fffffbfff165b7dd R11: ffffffff8b2dbeef R12: ffff88809457a600
R13: 0000000000000002 R14: 000000000000035b R15: ffff8880a76c5800
FS: 00007f6f11615700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff73a203db8 CR3: 000000009ae2a000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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