1
0
Fork 0
Fork of alistair23 Linux kernel for reMarkable from https://github.com/alistair23/linux
 
 
 
 
 
 
Go to file
Jann Horn acaab7335b lib/zlib: remove outdated and incorrect pre-increment optimization
The zlib inflate code has an old micro-optimization based on the
assumption that for pre-increment memory accesses, the compiler will
generate code that fits better into the processor's pipeline than what
would be generated for post-increment memory accesses.

This optimization was already removed in upstream zlib in 2016:
https://github.com/madler/zlib/commit/9aaec95e8211

This optimization causes UB according to C99, which says in section 6.5.6
"Additive operators": "If both the pointer operand and the result point to
elements of the same array object, or one past the last element of the
array object, the evaluation shall not produce an overflow; otherwise, the
behavior is undefined".

This UB is not only a theoretical concern, but can also cause trouble for
future work on compiler-based sanitizers.

According to the zlib commit, this optimization also is not optimal
anymore with modern compilers.

Replace uses of OFF, PUP and UP_UNALIGNED with their definitions in the
POSTINC case, and remove the macro definitions, just like in the upstream
patch.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Link: http://lkml.kernel.org/r/20200507123112.252723-1-jannh@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-04 19:06:25 -07:00
Documentation mm/debug: add tests validating architecture page table helpers 2020-06-04 19:06:21 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch powerpc/pseries/hotplug-memory: stop checking is_mem_section_removable() 2020-06-04 19:06:23 -07:00
block for-5.8/drivers-2020-06-01 2020-06-02 15:37:03 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto crypto: engine - do not requeue in case of fatal error 2020-05-28 17:27:52 +10:00
drivers zcomp: Use ARRAY_SIZE() for backends list 2020-06-04 19:06:24 -07:00
fs proc: rename "catch" function argument 2020-06-04 19:06:24 -07:00
include include/linux/mm.h: return true in cpupid_pid_unset() 2020-06-04 19:06:24 -07:00
init Merge branch 'akpm' (patches from Andrew) 2020-06-03 20:24:15 -07:00
ipc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-06-03 16:27:18 -07:00
kernel user.c: make uidhash_table static 2020-06-04 19:06:24 -07:00
lib lib/zlib: remove outdated and incorrect pre-increment optimization 2020-06-04 19:06:25 -07:00
mm mm: use false for bool variable 2020-06-04 19:06:24 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-06-03 16:27:18 -07:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-06-03 16:27:18 -07:00
scripts get_maintainer: fix unexpected behavior for path/to//file (double slashes) 2020-06-04 19:06:24 -07:00
security mm: add kvfree_sensitive() for freeing sensitive data objects 2020-06-04 19:06:22 -07:00
sound MIPS updates for v5.8: 2020-06-03 13:32:21 -07:00
tools Merge branch 'akpm' (patches from Andrew) 2020-06-03 20:24:15 -07:00
usr kbuild: fix comment about missing include guard detection 2020-04-11 12:09:48 +09:00
virt A fair amount of stuff this time around, dominated by yet another massive 2020-06-01 15:45:27 -07:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
.mailmap A fair amount of stuff this time around, dominated by yet another massive 2020-06-01 15:45:27 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS mailmap: change email for Ricardo Ribalda 2020-05-25 18:59:59 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS media updates for v5.8-rc1 2020-06-03 20:59:38 -07:00
Makefile arm64 updates for 5.8 2020-06-01 15:18:27 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.