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
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Sun, 24 Oct 2021 09:07:42 +0200
From:   Dmitry Vyukov <>
To:     Mike Rapoport <>
Cc:     Matthew Wilcox <>,
        Kees Cook <>,
        syzbot <>,
        Jordy Zomer <>,,,,
Subject: Re: [syzbot] WARNING: refcount bug in sys_memfd_secret

On Sun, 24 Oct 2021 at 07:38, Mike Rapoport <> wrote:
> On Sat, Oct 23, 2021 at 11:46:18PM +0100, Matthew Wilcox wrote:
> > On Sat, Oct 23, 2021 at 10:03:11AM -0700, Kees Cook wrote:
> > > On October 23, 2021 8:27:28 AM PDT, Mike Rapoport <> wrote:
> > > >and my first reaction was to send a revert the untested commit 110860541f44
> > > >("mm/secretmem: use refcount_t instead of atomic_t").
> >
> > I think you should.  This isn't a real problem.
> Do you mean that creation of 4 billion of file descriptors is not feasible?

FWIW I think refcount is at least capable of catching the issue I
described with the counter temporarily going below its true value.
With refcount it can be caught during fuzzing as refcount reaching 0
and then being incremented again. Basically this warning, but a true

Powered by blists - more mailing lists