Subj : Re: Deadlock (pthread) in signal handler
To   : comp.programming.threads
From : John Hickin
Date : Thu Apr 28 2005 05:08 pm


"Low Sze Hau" <szehau@gmail.com> wrote in message
news:d8de876f.0504280702.5edc5991@posting.google.com...
> I understand that calling a async-signal-safe function in signal
> handler can easily cause a deadlock.

Most of the time I'd assume that such functions are OK to call in a signal
handler.

>
> In my program, in certain condition it need to call exit() in signal

OK, exit() is NOT async signal safe.

> handler. The exit() function will actually call other registered
> cleanup functions from other library such as DB2. The program hangs

precisely because of what you just mentioned.

> when receive a signal interrupt and goes into a race condition
> (because of pthread try to acquire a mutex lock in malloc).
>

You can call _exit().

Your program has to cope with a dirty kill anyway (i.e., kill -KILL
your-pid). The besy way is to avoid complicated cleanup.


Regards, John.

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