Calling malloc from a signal handler

Jason Evans jasone at
Fri Sep 19 14:31:27 UTC 2008

Stephen Montgomery-Smith wrote:
> I notice that if you use "malloc" from within a signal handler on 
> FreeBSD-6.x, that you can potentially trigger a "recursive call" error.
> But this seems to have changed in FreeBSD-7.x.

The malloc implementation is completely new in FreeBSD 7, so not all of 
the internal error checking code is the same.

> Is it now permissible to call "malloc" from within a signal handler in 
> FreeBSD-7.x?

Calling malloc from within a signal handler can cause application 
deadlock, so although you won't see an error message printed, you are 
unlikely to be happy with the results.


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