acquiring duplicate lock of same type: "ftlk"

[Andriy Gapon]

acquiring duplicate lock of same type: "ftlk"
1st ftlk @ /usr/src/sys/compat/linux/linux_futex.c:177
2nd ftlk @ /usr/src/sys/compat/linux/linux_futex.c:203
KDB: stack backtrace:
db_trace_self_wrapper() at 0xffffffff801b1b9a = db_trace_self_wrapper+0x2a
kdb_backtrace() at 0xffffffff80391542 = kdb_backtrace+0x32
_witness_debugger() at 0xffffffff803a561c = _witness_debugger+0x2c
witness_checkorder() at 0xffffffff803a6640 = witness_checkorder+0x510
_sx_xlock() at 0xffffffff80367f78 = _sx_xlock+0x88
futex_get0() at 0xffffffff8055ba27 = futex_get0+0x1e7
linux_sys_futex() at 0xffffffff8055c74a = linux_sys_futex+0x58a
ia32_syscall() at 0xffffffff8054a574 = ia32_syscall+0x2a4
Xint0x80_syscall() at 0xffffffff80509425 = Xint0x80_syscall+0x95

-- 
Andriy Gapon