Date: Sat, 11 Aug 2001 16:07:28 -0500 From: Alfred Perlstein <bright@mu.org> To: Terry Lambert <tlambert2@mindspring.com> Cc: Michael Robinson <robinson@netrinsics.com>, current@FreeBSD.ORG, hackers@FreeBSD.ORG Subject: Re: _sigprocmask in malloc.c causes full file table? Message-ID: <20010811160728.U85642@elvis.mu.org> In-Reply-To: <3B75822F.E84799BD@mindspring.com>; from tlambert2@mindspring.com on Sat, Aug 11, 2001 at 12:06:23PM -0700 References: <200108110115.f7B1F4100321@netrinsics.com> <3B75822F.E84799BD@mindspring.com>
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* Terry Lambert <tlambert2@mindspring.com> [010811 14:06] wrote: > Michael Robinson wrote: > > > > I'm currently trying to deal with the problem where malloc/free in a > > signal handler will crash (in my case, the X window server) if a signal > > arrives during malloc or free. > > The manual pages suck, since this should be under signal(3), not > as a reference to sigaction(2), but... > > man 2 sigaction > > You can not allocate or free in signal handlers because malloc(3) > and free(3) use brk(2) and sbrk(2), which are system calls that > can't be used in a signal handler, since they are missing from > the list of permitted function. It's really the fact that malloc/free are not re-entrant that causes the problem. brk/sbrk by itself should be safe to call from a signal handler as they are syscalls and don't really share state with the process context in userland. -- -Alfred Perlstein [alfred@freebsd.org] Ok, who wrote this damn function called '??'? And why do my programs keep crashing in it? To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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