|
Date: Wed, 7 Dec 2016 17:26:18 +0100 From: Peter Zijlstra <peterz@...radead.org> To: David Windsor <dwindsor@...il.com> Cc: Liljestrand Hans <ishkamiel@...il.com>, "Reshetova, Elena" <elena.reshetova@...el.com>, "kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>, Greg KH <gregkh@...uxfoundation.org>, Kees Cook <keescook@...omium.org>, "will.deacon@....com" <will.deacon@....com>, Boqun Feng <boqun.feng@...il.com>, "aik@...abs.ru" <aik@...abs.ru>, "david@...son.dropbear.id.au" <david@...son.dropbear.id.au> Subject: Re: Conversion from atomic_t to refcount_t: summary of issues On Wed, Dec 07, 2016 at 10:59:47AM -0500, David Windsor wrote: > On Wed, Dec 7, 2016 at 8:52 AM, Peter Zijlstra <peterz@...radead.org> wrote: > > All in all I'm not inclined to add {add,sub.inc,dec}_return() to > > refcount, as previously stated, they don't make sense. > > Is the plan now to audit all {add,sub,inc,dec}_return() call sites? > This should probably happen anyway, due to the amount of funkiness > uncovered by Hans' mini-audit. Then we can rewrite actual reference > counting code that calls the unsupported {add,sub,inc,dec}_return() to > use something else? The ip_vs_dest cache thing would receive 2 patches, one doing the global +1, the second conversion to refcount_t. For BPF we'd need to talk to Alexei to see if the custom limit still makes sense, but I'd be inclined to simply drop that in the refcount_t conversion. As to the tty and usb-gadget ones, those constructs are actually racy, but I'm not sure the races matter. But I would certainly prefer to rework then to be race-free. But I wouldn't go so far as to audit all *_return calls, just those that pop up while hunting refcounts.
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.