linux-kernel - [PATCHv5 0/8] ACCESS_ONCE and non-scalar accesses

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1418306712-17245-1-git-send-email-borntraeger@de.ibm.com>
Date:	Thu, 11 Dec 2014 15:05:03 +0100
From:	Christian Borntraeger <borntraeger@...ibm.com>
To:	linux-kernel@...r.kernel.org
Cc:	linux-arch@...r.kernel.org, paulmck@...ux.vnet.ibm.com,
	torvalds@...ux-foundation.org, George Spelvin <linux@...izon.com>,
	Christian Borntraeger <borntraeger@...ibm.com>,
	linux-mm@...ck.org
Subject: [PATCHv5 0/8]  ACCESS_ONCE and non-scalar accesses

As discussed on LKML http://marc.info/?i=54611D86.4040306%40de.ibm.com
ACCESS_ONCE might fail with specific compilers for non-scalar accesses.

Here is a set of patches to tackle that problem.

The first patch introduce READ_ONCE and ASSIGN_ONCE. If the data structure
is larger than the machine word size memcpy is used and a warning is emitted.
The next patches fix up all in-tree users of ACCESS_ONCE on non-scalar types.

Due to all the trouble when dealing with linux-next, I will defer the patch
that forces ACCESS_ONCE to work only on scalar types after rc1 to give it
a full spin in linux-next.

If nobody complains I will ask Linus to pull this for 3.19 next week.
The tree can be found at 

git://git.kernel.org/pub/scm/linux/kernel/git/borntraeger/linux.git linux-next

Changelog:
v4->v5:
1. READ_ONCE/ASSIGN_ONCE use x instead of p
2. linux/types.h --> uapi/linux/types.h u??-->__u?? to avoid header
   inclusion fun and compile errors
3. Actually provide data_access_exceeds_word_size.
4. also move handle_pte_fault to a barrier as there is ppc44x which has
   64bit ptes and 32bit word size. Some sanity check from a VM person
   would be good.

Cc: linux-mm@...ck.org

Christian Borntraeger (8):
  kernel: Provide READ_ONCE and ASSIGN_ONCE
  mm: replace ACCESS_ONCE with READ_ONCE or barriers
  x86/spinlock: Replace ACCESS_ONCE with READ_ONCE
  x86/gup: Replace ACCESS_ONCE with READ_ONCE
  mips/gup: Replace ACCESS_ONCE with READ_ONCE
  arm64/spinlock: Replace ACCESS_ONCE READ_ONCE
  arm/spinlock: Replace ACCESS_ONCE with READ_ONCE
  s390/kvm: REPLACE barrier fixup with READ_ONCE

 arch/arm/include/asm/spinlock.h   |  4 +--
 arch/arm64/include/asm/spinlock.h |  4 +--
 arch/mips/mm/gup.c                |  2 +-
 arch/s390/kvm/gaccess.c           | 18 ++++------
 arch/x86/include/asm/spinlock.h   |  8 ++---
 arch/x86/mm/gup.c                 |  2 +-
 include/linux/compiler.h          | 70 +++++++++++++++++++++++++++++++++++++++
 lib/Makefile                      |  2 +-
 lib/access.c                      |  8 +++++
 mm/gup.c                          |  2 +-
 mm/memory.c                       | 11 +++++-
 mm/rmap.c                         |  3 +-
 12 files changed, 108 insertions(+), 26 deletions(-)
 create mode 100644 lib/access.c

-- 
1.9.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/