WARNING in do_dentry_open (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: c677124e Merge branch 'sched-core-for-linus' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=157511bee00000
kernel config: https://syzkaller.appspot.com/x/.config?x=a4c9892b0ce783fa
dashboard link: https://syzkaller.appspot.com/bug?extid=32c9f7d8a32ea5127669
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1476cf66e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1640085ee00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+32c9f7...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 10428 at fs/open.c:832 do_dentry_open+0xf65/0x1380 fs/open.c:832
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 10428 Comm: syz-executor099 Not tainted 5.5.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x197/0x210 lib/dump_stack.c:118
panic+0x2e3/0x75c kernel/panic.c:221
__warn.cold+0x2f/0x3e kernel/panic.c:582
report_bug+0x289/0x300 lib/bug.c:195
fixup_bug arch/x86/kernel/traps.c:174 [inline]
fixup_bug arch/x86/kernel/traps.c:169 [inline]
do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286
invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:do_dentry_open+0xf65/0x1380 fs/open.c:832
Code: ea 03 80 3c 02 00 0f 85 9b 03 00 00 49 8b 46 70 48 85 c0 48 89 85 40 ff ff ff 0f 84 d9 f5 ff ff e9 72 f5 ff ff e8 4b b8 b8 ff <0f> 0b 41 bd ea ff ff ff e9 89 fd ff ff 48 8b bd 50 ff ff ff e8 02
RSP: 0018:ffffc90001e179f8 EFLAGS: 00010293
RAX: ffff888087b7c140 RBX: ffff888085e25ac0 RCX: ffffffff81bc8442
RDX: 0000000000000000 RSI: ffffffff81bc86b5 RDI: 0000000000000005
RBP: ffffc90001e17ad8 R08: ffff888087b7c140 R09: ffffed1014e9f962
R10: ffffed1014e9f961 R11: ffff8880a74fcb0b R12: ffff888219bc7040
R13: 0000000000000001 R14: ffffffff885e8680 R15: ffff888085e25ae8
vfs_open+0xa0/0xd0 fs/open.c:914
do_last fs/namei.c:3359 [inline]
path_openat+0x1141/0x2fb0 fs/namei.c:3476
do_filp_open+0x1a1/0x280 fs/namei.c:3506
do_sys_open+0x3fe/0x5d0 fs/open.c:1097
__do_sys_openat fs/open.c:1124 [inline]
__se_sys_openat fs/open.c:1118 [inline]
__x64_sys_openat+0x9d/0x100 fs/open.c:1118
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440229
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc7f2488b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440229
RDX: 0000000000000002 RSI: 0000000020000000 RDI: ffffffffffffff9c
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401ab0
R13: 0000000000401b40 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Al Viro]

On Sat, Feb 01, 2020 at 01:48:11AM -0800, syzbot wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: c677124e Merge branch 'sched-core-for-linus' of git://git...
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=157511bee00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=a4c9892b0ce783fa
> dashboard link: https://syzkaller.appspot.com/bug?extid=32c9f7d8a32ea5127669
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1476cf66e00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1640085ee00000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+32c9f7...@syzkaller.appspotmail.com

security_file_open() or ->open() of some file returning a positive number. No way
to tell which one (or which file had that been) without a reproducer...

[syzbot]

> Already fixed as commit a37f4958f7b63d2b.
>
> #syz fix: debugfs: Return -EPERM when locked down

Your 'fix:' command is accepted, but please keep syzkall...@googlegroups.com mailing list in CC next time. It serves as a history of what happened with each bug report. Thank you.