Date: Tue, 08 Sep 1998 01:59:59 +0100 From: Brian Somers <brian@Awfulhak.org> To: HighWind Software Information <info@highwind.com> Cc: freebsd-current@FreeBSD.ORG Subject: Re: free() called recursively Message-ID: <199809080100.CAA03464@woof.lan.awfulhak.org> In-Reply-To: Your message of "Mon, 07 Sep 1998 16:29:18 EDT." <199809072029.QAA03642@highwind.com>
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> How bad is it to get this:
> "t_activefile in free(): warning: recursive call."
Very.
> We are using gcc for C++. One of our test programs which tests code
> that currently sends our application out into "la-la land" seems to
> print this every few runs. During those runs, it also goes off into
> "la-la land".
>
> "la-la land" == running but going nowhere. ktrace shows nothing,
> application only dies with "kill -9".
>
> We do link against libc_r. I'm wondering if this recursive call thing
> is a serious problem and what we can do about it.
>
> -Rob
It's *usually* (sometimes?) caused by code that does complicated
things in frequently called signal handlers - perhaps a SIGALRM
handler. It *may* happen because of something as simple as a
printf() in a SIGUSR1 if the signal happens during a malloc()/free()
and printf() feels inclined to do a malloc() or free().
If your program uses frequent signals, you should probably defer the
processing 'till after the return of the signal handler to avoid
these problems. An example can be found in src/usr.sbin/ppp/sig.c.
--
Brian <brian@Awfulhak.org>, <brian@FreeBSD.org>, <brian@OpenBSD.org>
<http://www.Awfulhak.org>;
Don't _EVER_ lose your sense of humour....
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