Date: Sat, 26 May 2018 02:29:53 +0800 From: Marcelo Araujo <araujobsdport@gmail.com> To: Brooks Davis <brooks@freebsd.org> Cc: Eitan Adler <lists@eitanadler.com>, src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r334199 - head/usr.sbin/bhyve Message-ID: <CAOfEmZhHTffQ03-TR7-MG4mj5PefwDDiKo_WkRyre7TQurZzEg@mail.gmail.com> In-Reply-To: <20180525182139.GE99063@spindle.one-eyed-alien.net> References: <201805250207.w4P275Pf060725@repo.freebsd.org> <20180525151134.GB99063@spindle.one-eyed-alien.net> <CAOfEmZgV9yssn5v8ZpbkwL=rrifoD1Z=uRxe6a0KyM3mrXrSjQ@mail.gmail.com> <CAF6rxgm32%2B_XazDvbtyFChPigxVB0HQ30r3=CvN65ko=zHq0yA@mail.gmail.com> <CAOfEmZhS4RZPn6%2BqOcU56HUtUgGids79cS=fBKfuGjpBBQQm5g@mail.gmail.com> <20180525174424.GD99063@spindle.one-eyed-alien.net> <CAOfEmZhm3HPGU3r2nK9o3ry8%2BxpzaFRDCgw3qCKgy2CTOu3NaQ@mail.gmail.com> <20180525182139.GE99063@spindle.one-eyed-alien.net>
next in thread | previous in thread | raw e-mail | index | archive | help
2018-05-26 2:21 GMT+08:00 Brooks Davis <brooks@freebsd.org>: > On Sat, May 26, 2018 at 01:56:28AM +0800, Marcelo Araujo wrote: > > 2018-05-26 1:44 GMT+08:00 Brooks Davis <brooks@freebsd.org>: > > > > > On Sat, May 26, 2018 at 01:21:33AM +0800, Marcelo Araujo wrote: > > > > On Sat, May 26, 2018, 1:11 AM Eitan Adler <lists@eitanadler.com> > wrote: > > > > > > > > > On 25 May 2018 at 08:23, Marcelo Araujo <araujobsdport@gmail.com> > > > wrote: > > > > > > > > > > > > > > > > > > On Fri, May 25, 2018, 11:11 PM Brooks Davis <brooks@freebsd.org> > > > wrote: > > > > > >> > > > > > >> On Fri, May 25, 2018 at 02:07:05AM +0000, Marcelo Araujo wrote: > > > > > >> > Author: araujo > > > > > >> > Date: Fri May 25 02:07:05 2018 > > > > > >> > New Revision: 334199 > > > > > >> > URL: https://svnweb.freebsd.org/changeset/base/334199 > > > > > >> > > > > > > >> > Log: > > > > > >> > Fix a memory leak on topology_parse(). > > > > > >> > > > > > > >> > strdup(3) allocates memory for a copy of the string, does > the > > > copy > > > > > and > > > > > >> > returns a pointer to it. If there is no sufficient memory > NULL > > > is > > > > > >> > returned > > > > > >> > and the global errno is set to ENOMEM. > > > > > >> > We do a sanity check to see if it was possible to allocate > > > enough > > > > > >> > memory. > > > > > >> > > > > > > >> > Also as we allocate memory, we need to free this memory > used. > > > Or it > > > > > >> > will > > > > > >> > going out of scope leaks the storage it points to. > > > > > >> > > > > > > >> > Reviewed by: rgrimes > > > > > >> > MFC after: 3 weeks. > > > > > >> > X-MFC: r332298 > > > > > >> > Sponsored by: iXsystems Inc. > > > > > >> > Differential Revision: https://reviews.freebsd.org/ > D15550 > > > > > >> > > > > > > >> > Modified: > > > > > >> > head/usr.sbin/bhyve/bhyverun.c > > > > > >> > > > > > > >> > Modified: head/usr.sbin/bhyve/bhyverun.c > > > > > >> > > > > > > >> > > > > > > ============================================================ > > > ================== > > > > > >> > --- head/usr.sbin/bhyve/bhyverun.c Fri May 25 01:38:59 2018 > > > > > >> > (r334198) > > > > > >> > +++ head/usr.sbin/bhyve/bhyverun.c Fri May 25 02:07:05 2018 > > > > > >> > (r334199) > > > > > >> > @@ -193,6 +193,7 @@ topology_parse(const char *opt) > > > > > >> > c = 1, n = 1, s = 1, t = 1; > > > > > >> > ns = false, scts = false; > > > > > >> > str = strdup(opt); > > > > > >> > + assert(str != NULL); > > > > > >> > > > > > >> Using assert seems like an odd choice when you've already added > a > > > > > >> failure path and the strsep will crash immediately if assert is > > > elided. > > > > > > > > > > > > > > > > > > Just to make a better point, I had the same discussion about > > > assert(3) in > > > > > > another review, we don't do NDEBUG even for RELEASE. > > > > > > > > > > IMHO we only use assert for asserting things ought to never be > false > > > > > except in buggy code. Using assert for handling is poor practice. > > > > > > > > > > > > > Again, in this case we are using it all over the place and we must > > > replace > > > > it. Also we should document it in somewhere perhaps in the assert(3) > > > > otherwise myself and others will keep using it. If you use find, not > only > > > > myself is using it to check strdup! So what is the suggestion to > handle > > > > assert(3)? Deprecated it? > > > > > > Code that uses assert() in place of error handling is wrong and should > > > be fixed. assert(condition) means that condition must never happen > > > and if it does a bug has occurred (or the programmers assumptions are > > > wrong). In this case failure would not be due to a bug, but do to > > > resource exhaustion which is expected to be handled. > > > > > > > I agree with you! We have plenty of place that use strdup(3) without > check > > the errno ENOMEN return; so do you think would be better bypass a errno > > ENOMEN without check it and have a crash, or better abort(3) using > > assert(3) in case we have no memory available to allocated the memory > for a > > copy of a string? > > The correct code here would be one of: > > str = strdup(opt); > if (str == NULL) > goto out; > > str = strdup(opt); > if (str == NULL) > err(1, "unable to allocate option memory"); > One more thing, exit with err(1) is wrong, 1 is EPERM and should be 12 ENOMEN! :D > > > Personally I don't mind make couple extra lines of code to call abort(3) > or > > exit(3), but till there, if we don't make RELEASE using NDEBUG, what you > > guys are saying to me is more personal preference than anything else. > > The fact that we don't do NDEBUG builds normally does not allow us to > ignore that it exists. It's perfectly reasonable for a user to build > with CFLAGS+=NDEBUG. That need to work. If code is going to fail to > handle resource errors with NDEBUG set then it needs something like this > at the top of the file: > > #ifdef NDEBUG > #error The code depends on assert() for error handling > #endif > > -- Brooks > -- -- Marcelo Araujo (__)araujo@FreeBSD.org \\\'',)http://www.FreeBSD.org <http://www.freebsd.org/>; \/ \ ^ Power To Server. .\. /_)
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAOfEmZhHTffQ03-TR7-MG4mj5PefwDDiKo_WkRyre7TQurZzEg>