From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Date: Wed, 01 Aug 2018 11:28:47 +0000 Subject: Re: SLAB_TYPESAFE_BY_RCU without constructors (was Re: [PATCH v4 13/17] khwasan: add hooks implement Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: dccp@vger.kernel.org On 08/01/2018 03:34 AM, Dmitry Vyukov wrote: > On Wed, Aug 1, 2018 at 12:23 PM, Eric Dumazet wrote: >> On 08/01/2018 02:03 AM, Andrey Ryabinin wrote: >> >>> I can't think of any advantage in not having the constructor. >> >> I can't see any advantage adding another indirect call, >> in RETPOLINE world. > > Can you please elaborate what's the problem here? > If slab ctor call have RETPOLINE, then using ctors more does not > introduce any security problems and they are not _that_ slow. They _are_ slow, when we have dozens of them in a code path. I object "having to add" yet another indirect call, if this can be avoided [*] If some people want to use ctor, fine, but do not request this. [*] This can be tricky, but worth the pain.