Date: Tue, 17 Sep 2019 17:27:49 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Toomas Soome <tsoome@me.com> Cc: Toomas Soome <tsoome@FreeBSD.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r352421 - head/stand/libsa Message-ID: <20190917142749.GB2559@kib.kiev.ua> In-Reply-To: <6762A429-F17F-46D1-A55B-BD9C627D6903@me.com> References: <201909162028.x8GKS9jK064079@repo.freebsd.org> <20190917085641.GY2559@kib.kiev.ua> <6762A429-F17F-46D1-A55B-BD9C627D6903@me.com>
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On Tue, Sep 17, 2019 at 12:05:26PM +0300, Toomas Soome wrote: > > > > On 17 Sep 2019, at 11:56, Konstantin Belousov <kostikbel@gmail.com> wrote: > > > > On Mon, Sep 16, 2019 at 08:28:09PM +0000, Toomas Soome wrote: > >> Author: tsoome > >> Date: Mon Sep 16 20:28:08 2019 > >> New Revision: 352421 > >> URL: https://svnweb.freebsd.org/changeset/base/352421 > >> > >> Log: > >> loader: Malloc(0) should return NULL. > >> > >> We really should not allocate anything with size 0. > > Why ? This is quite unexpected from other environments, where > > malloc(0) returns unique object. > > > > Hiding bugs. And, we are not getting unique object, we are getting chunk of memory with payload length of 0 and the memory content depends on if head and tail guards are used - the chunk is with size at least MALLOCALIGN (16 or 64 bytes) and the chunk is from random location of heap. > Yes, exactly, this is how all other mallocs behave.
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