panic: inconsistent poll.fdMutex

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 82673a188a32 Add per-CPU caches to the pmemrange allocator.
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=12bb6088980000
kernel config: https://syzkaller.appspot.com/x/.config?x=7058272de1526588
dashboard link: https://syzkaller.appspot.com/bug?extid=40e3ab245649432af357

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5180d22f4f58/disk-82673a18.raw.xz
bsd.gdb: https://storage.googleapis.com/syzbot-assets/f1913314daca/bsd-82673a18.gdb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c4a343183259/kernel-82673a18.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+40e3ab...@syzkaller.appspotmail.com

panic: inconsistent poll.fdMutex

goroutine 54 [running]:
internal/poll.(*fdMutex).rwunlock(0xc0003f9990?, 0x27?)
/usr/local/go/src/internal/poll/fd_mutex.go:179 +0xde
internal/poll.(*FD).readUnlock(0xc0003bb080)
/usr/local/go/src/internal/poll/fd_mutex.go:231 +0x1f
internal/poll.(*FD).Read(0xc0003bb080, {0xc0000131a0, 0xc, 0xc})
/usr/local/go/src/internal/poll/fd_unix.go:170 +0x351
os.(*File).read(...)
/usr/local/go/src/os/file_posix.go:29
os.(*File).Read(0xc000060138, {0xc0000131a0?, 0xc0003f9ab0?, 0x411ae5?})
/usr/local/go/src/os/file.go:118 +0x52
io.ReadAtLeast({0xd250a0, 0xc000060138}, {0xc0000131a0, 0xc, 0xc}, 0xc)
/usr/local/go/src/io/io.go:335 +0x90
io.ReadFull(...)
/usr/local/go/src/io/io.go:354
github.com/google/syzkaller/pkg/ipc.(*command).exec(0xc0000d6980, 0xc0003f9e80?, {0x0, 0x0, 0x0})
/syzkaller/gopath/src/github.com/google/syzkaller/pkg/ipc/ipc.go:840 +0x567
github.com/google/syzkaller/pkg/ipc.(*Env).ExecProg(0xc0000d6680, 0xc0003f9e80, {0xc00028ef00, 0x2371, 0x2371})
/syzkaller/gopath/src/github.com/google/syzkaller/pkg/ipc/ipc.go:317 +0x15e
main.(*Proc).execute(0xc0003046c0, {0xb7e, {0xc00028ef00, 0x2371, 0x2371}, {0x15, 0x4762, 0x0}, 0x1, 0x0, ...})
/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/proc.go:87 +0x15b
main.(*Proc).loop(0xc0003046c0)
/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/proc.go:48 +0x158
created by main.startProc in goroutine 1
/syzkaller/gopath/src/github.com/google/syzkaller/syz-fuzzer/proc.go:35 +0x11b


---
This report 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 issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup