From: Darren Hart <dvhart@infradead.org>
To: Jiri Slaby <jslaby@suse.cz>
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>,
Will Deacon <will.deacon@arm.com>,
Max Filippov <jcmvbkbc@gmail.com>,
Paul Mackerras <paulus@samba.org>,
"H. Peter Anvin" <hpa@zytor.com>,
sparclinux@vger.kernel.org, tglx@linutronix.de,
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>,
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 <ste>
Subject: Re: [PATCH 1/1] futex: remove duplicated code and fix UB
Date: Thu, 22 Jun 2017 03:53:37 +0000 [thread overview]
Message-ID: <20170622035337.GF25900@fury> (raw)
In-Reply-To: <20170621115318.2781-1-jslaby@suse.cz>
On Wed, Jun 21, 2017 at 01:53:18PM +0200, Jiri Slaby wrote:
> There is code duplicated over all architecture's headers for
> futex_atomic_op_inuser. Namely op decoding, access_ok check for uaddr,
> and comparison of the result.
>
> Remove this duplication and leave up to the arches only the needed
> assembly which is now in arch_futex_atomic_op_inuser.
>
> This effectively distributes the Will Deacon's arm64 fix for undefined
> behaviour reported by UBSAN to all architectures. The fix was done in
> commit 5f16a046f8e1 (arm64: futex: Fix undefined behaviour with
> FUTEX_OP_OPARG_SHIFT usage). Look there for an example dump.
>
> Note that s390 removed access_ok check in d12a29703 ("s390/uaccess:
> remove pointless access_ok() checks") as access_ok there returns true.
> We introduce it back to the helper for the sake of simplicity (it gets
> optimized away anyway).
>
This required a minor manual merge for ARM on the tip of Linus' tree today. The
reduced duplication is a welcome improvement.
Reviewed-by: Darren Hart (VMware) <dvhart@infradead.org>
--
Darren Hart
VMware Open Source Technology Center
next prev parent reply other threads:[~2017-06-22 3:53 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-15 13:07 [PATCH 1/1] futex: remove duplicated code Jiri Slaby
2017-05-15 13:16 ` Will Deacon
2017-05-17 8:01 ` Jiri Slaby
2017-05-18 17:30 ` Will Deacon
2017-05-22 21:11 ` Thomas Gleixner
2017-05-25 14:28 ` Will Deacon
2017-05-26 6:54 ` Thomas Gleixner
2017-06-21 11:53 ` [PATCH 1/1] futex: remove duplicated code and fix UB Jiri Slaby
2017-06-22 3:53 ` Darren Hart [this message]
2017-06-23 7:51 ` Thomas Gleixner
2017-06-26 12:02 ` Jiri Slaby
2017-06-26 12:08 ` Will Deacon
2017-07-03 10:18 ` Thomas Gleixner
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