From: Thomas Gleixner <tglx@linutronix.de>
To: Will Deacon <will.deacon@arm.com>
Cc: linux-mips@linux-mips.org, Rich Felker <dalias@libc.org>,
linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org,
peterz@infradead.org,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Max Filippov <jcmvbkbc@gmail.com>,
Paul Mackerras <paulus@samba.org>,
"H. Peter Anvin" <hpa@zytor.com>,
sparclinux@vger.kernel.org, Jiri Slaby <jslaby@suse.cz>,
Jonas Bonn <jonas@southpole.se>,
linux-s390@vger.kernel.org, linux-arch@vger.kernel.org,
Yoshinori Sato <ysato@users.sourceforge.jp>,
linux-hexagon@vger.kernel.org, Helge Deller <deller@gmx.de>,
x86@kernel.org, "James E.J. Bottomley" <jejb@parisc-linux.org>,
mingo@redhat.com, Catalin Marinas <catalin.marinas@arm.com>,
dvhart@infradead.org, Matt Turner <mattst88@gmail.com>,
linux-snps-arc@lists.infradead.org,
Fenghua Yu <fenghua.yu@intel.com>, Arnd Bergmann <arnd@arndb.de>,
linux-xtensa@linux-xtensa.org, Stefan Kristiansson <stefan>
Subject: Re: [PATCH v2 1/1] futex: remove duplicated code and fix UB
Date: Fri, 25 Aug 2017 22:43:41 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.20.1708252243020.2124@nanos> (raw)
In-Reply-To: <20170824094756.GA6346@arm.com>
On Thu, 24 Aug 2017, Will Deacon wrote:
> On Thu, Aug 24, 2017 at 09:31:05AM +0200, Jiri Slaby wrote:
> > +static int futex_atomic_op_inuser(unsigned int encoded_op, u32 __user *uaddr)
> > +{
> > + unsigned int op = (encoded_op & 0x70000000) >> 28;
> > + unsigned int cmp = (encoded_op & 0x0f000000) >> 24;
> > + int oparg = sign_extend32((encoded_op & 0x00fff000) >> 12, 12);
> > + int cmparg = sign_extend32(encoded_op & 0x00000fff, 12);
> > + int oldval, ret;
> > +
> > + if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) {
> > + if (oparg < 0 || oparg > 31)
> > + return -EINVAL;
> > + oparg = 1 << oparg;
> > + }
> > +
> > + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
> > + return -EFAULT;
> > +
> > + ret = arch_futex_atomic_op_inuser(op, oparg, &oldval, uaddr);
> > + if (ret)
> > + return ret;
>
> We could move the pagefault_{disable,enable} calls here, and then remove
> them from the futex_atomic_op_inuser callsites elsewhere in futex.c
Correct, but we can do that after getting this in.
Thanks,
tglx
prev parent reply other threads:[~2017-08-25 20:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20170824073105.c_kCYybEyHVKRNOXJXUwSitYqCgI4MgVUz9SzmE8kQw@z>
2017-08-24 7:31 ` [PATCH v2 1/1] futex: remove duplicated code and fix UB Jiri Slaby
[not found] ` <20170824094756.0mu6esGyyYEkZOmizWB6dUdzNkCxwkNdChVQQpQ_nVw@z>
2017-08-24 9:47 ` Will Deacon
2017-08-25 20:43 ` Thomas Gleixner [this message]
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