[PATCH] futexes / now: duplicate lock of same type

[Lucius Windschuh]

2009/2/10 Chagin Dmitry <dchagin at freebsd.org>:
>> > please, try http://lnxx64.googlecode.com/files/futexes_partial_II.patch
>> > first patch fail at i386...

I am using your patch and Flash got a bit faster. :-)
But witness reported this when I start my opera and load mail.google.com:

acquiring duplicate lock of same type: "futex lock"
 1st futex lock @
/usr/src/sys/modules/linux/../../compat/linux/linux_futex.c:179
 2nd futex lock @
/usr/src/sys/modules/linux/../../compat/linux/linux_futex.c:211
KDB: stack backtrace:
db_trace_self_wrapper(c09b535c,eb1d7b50,c06da5a5,4,c09b0871,...) at
db_trace_self_wrapper+0x26
kdb_backtrace(4,c09b0871,c0d62685,c6112d88,eb1d7bac,...) at kdb_backtrace+0x29
_witness_debugger(c09b7f74,c0d626e7,c0d62685,d3,c09ab01b,...) at
_witness_debugger+0x25
witness_checkorder(c7526b80,9,c0d62685,d3,0,...) at witness_checkorder+0x469
_sx_xlock(c7526b80,0,c0d62685,d3,0,...) at _sx_xlock+0x85
futex_get0(0,0,102,c7526b80,0,...) at futex_get0+0x28c
futex_get_op(eb1d7c44,eb1d7c58,c068ba4c,c770f088,4,...) at futex_get_op+0x93
linux_sys_futex(c77336c0,eb1d7cf8,eb1d7d18,eb1d7d1c,c0d65b20,...) at
linux_sys_futex+0x6a
syscall(eb1d7d38) at syscall+0x283
Xint0x80_syscall() at Xint0x80_syscall+0x20
--- syscall (240, Linux ELF, linux_sys_futex), eip = 0x28cd69b3, esp =
0xbfbfde6c, ebp = 0x4000001 ---

Is this message potentially harmful?

More information can be gathered on request (e.g. textdump with a
custom ddb script).

Regards

Lucius