lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <20171223130621.GA3994@bombadil.infradead.org> Date: Sat, 23 Dec 2017 05:06:21 -0800 From: Matthew Wilcox <willy@...radead.org> To: Josh Triplett <josh@...htriplett.org> Cc: Ross Zwisler <ross.zwisler@...ux.intel.com>, linux-kernel@...r.kernel.org, Dave Hansen <dave.hansen@...el.com>, linux-mm@...ck.org, Matthew Wilcox <mawilcox@...rosoft.com>, linux-sparse@...r.kernel.org Subject: Re: [PATCH 2/2] Introduce __cond_lock_err On Sat, Dec 23, 2017 at 01:39:11AM -0800, Josh Triplett wrote: > +linux-sparse Ehh ... we've probably trimmed too much to give linux-sparse a good summary. Here're the important lines from my patch: +# define __cond_lock_err(x,c) ((c) ? 1 : ({ __acquire(x); 0; })) + return __cond_lock_err(*ptlp, __follow_pte_pmd(mm, address, start, end, + ptepp, pmdpp, ptlp)); This is supposed to be "If "c" is an error value, we don't have a lock, otherwise we have a lock". And to translate from linux-speak into sparse-speak: # define __acquire(x) __context__(x,1) Josh & Ross pointed out (quite correctly) that code which does something like if (foo()) return; will work with this, but code that does if (foo() < 0) return; will not because we're now returning 1 instead of -ENOMEM (for example). So they made the very sensible suggestion that I change the definition of __cond_lock to: # define __cond_lock_err(x,c) ((c) ?: ({ __acquire(x); 0; })) Unfortunately, when I do that, the context imbalance warning returns. As I said below, this is with sparse 0.5.1. > On Fri, Dec 22, 2017 at 05:36:34AM -0800, Matthew Wilcox wrote: > > On Fri, Dec 22, 2017 at 04:31:12AM -0800, Matthew Wilcox wrote: > > > On Thu, Dec 21, 2017 at 08:21:20PM -0800, Josh Triplett wrote: > > > > On Thu, Dec 21, 2017 at 05:10:00PM -0800, Matthew Wilcox wrote: > > > > > Yes, but this define is only #if __CHECKER__, so it doesn't matter what we > > > > > return as this code will never run. > > > > > > > > It does matter slightly, as Sparse does some (very limited) value-based > > > > analyses. Let's future-proof it. > > > > > > > > > That said, if sparse supports the GNU syntax of ?: then I have no > > > > > objection to doing that. > > > > > > > > Sparse does support that syntax. > > > > > > Great, I'll fix that and resubmit. > > > > Except the context imbalance warning comes back if I do. This is sparse > > 0.5.1 (Debian's 0.5.1-2 package). > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@...ck.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@...ck.org"> email@...ck.org </a>
Powered by blists - more mailing lists