14 Jun
2010
14 Jun
'10
4:11 p.m.
On Sunday 13 June 2010, Stefan Keller wrote:
I used the shm_regex functions from lib in one of my
own modules and
noticed that it is dead-locking (it hangs in FUTEX_WAIT).
The code hangs in regexec() when trying to acquire the lock. This was
a bit hard to find out as I couldn't reproduce it in a virtual
machine with some test code I wrote. It turns out this only happens if
the machine has more than one physical CPU core.
Reproducable on x86_64 with two CPU cores, glibc 2.3.6 (from Debian
Etch) and glibc 2.11.1 (from Ubuntu Jaunty).
Attached is a patch which does its own locking and thus works around
this problem.
Hi Stefan,
thank you for the patch, it looks fine to me on a first sight. The library in
question is not used in any of the existing modules, so i think it should be
pretty save. Miklos, its ok when i apply it, or do you maybe want to refine it
a bit?
Regards,
Henning