From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Frysinger Date: Fri, 22 Oct 2010 13:06:14 -0400 Subject: [U-Boot] [PATCH] Prevent malloc with size 0 In-Reply-To: References: <4CC006B1.8000905@intracomdefense.com> <201010221118.06690.vapier@gentoo.org> Message-ID: <201010221306.15686.vapier@gentoo.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Friday, October 22, 2010 12:40:07 Joakim Tjernlund wrote: > Mike Frysinger wrote on 2010/10/22 17:18:05: > > On Friday, October 22, 2010 04:34:52 Joakim Tjernlund wrote: > > > Don't you want to know if the app screwed up or if the system is out > > > of memory? > > > > > > The only upside to malloc(0) == NULL I can see is an extra check > > > for apps for which size == 0 is an error to the app too(something the > > > app should have checked itself long before calling malloc). > > > > if an app is doing malloc(0), it is broken. i'm really not worried at > > all > > In your opinion, not mine and not POSIX either. I outlined uses for > malloc(0) earlier. i havent seen any realistic usage examples. the only ones you quoted could easily be solved in a different way assuming they were even affected by malloc(0). > > about detecting OOM state. my real world experience thus far has shown > > no actual problems with this behavior. so unless you have some actual > > examples where this behavior "harms" u-boot, i say we merge the OP's > > patch. > > Since you think an app is broken if it does malloc(0), it should not matter > what malloc(0) returns to you. You only gain an extra error check for the > broken app at the expense of ease of use and sane error checking in > general. more like you notice that the code is broken right away. the few times i have seen a malloc(0), it was do to errors elsewhere in the code and once those were fixed, malloc() wasnt called with a size 0. > I prefer not to make it easier for broken apps when it hurts elsewhere. funny, i can use the same logic to ban malloc(0). it makes you notice & fix errors without penalties. > Ah, IT changed some settings globally. I changed it back. I hope this reply > is better. yes, this is much better. thanks ! -mike -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 836 bytes Desc: This is a digitally signed message part. Url : http://lists.denx.de/pipermail/u-boot/attachments/20101022/0b9082f7/attachment.pgp