How to determine the thread holding a mutex?

How to determine the thread holding a mutex?

[xxhdx1985126]

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Hi, everyone.

I'm trying to debug a problem that appears to be a deadlock. I wonder if I can use gdb to find out which thread is holding a mutex. If so, my work would be much easier, as there are many threads in my program.

Please help me, Thank you:-)\x16º&ÖëzÛ«ŸŽy×¹b²Ö«r\x18\x1d

Re: How to determine the thread holding a mutex?

[Philippe Waroquiers]

On Tue, 2017-01-10 at 18:34 +0800, xxhdx1985126 wrote:
> Hi, everyone.
> 
> I'm trying to debug a problem that appears to be a deadlock. I wonder 
> if I can use gdb to find out which thread is holding a mutex.
>  If so, my work would be much easier, as there are many threads in my program.

What you can do is to use valgrind --tool=helgrind 
to first see if valgrind helgrind tool does not point at a possible
culprit for the deadlock.

Assuming helgrind does not explain the bug, and assuming that the
deadlock reproduces under valgrind/helgrind,
you can use the valgrind gdbserver monitor command 'info locks'
to obtain the list of locks 
See
http://www.valgrind.org/docs/manual/hg-manual.html#hg-manual.monitor-commands
and
http://www.valgrind.org/docs/manual/manual-core-adv.html#manual-core-adv.gdbserver

for more information.


Philippe