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Linus Torvalds 1340283741 flexible-array member convertion patches for 5.7-rc2
Hi Linus,
 
 Please, pull the following patches that replace zero-length arrays with
 flexible-array members.
 
 The current codebase makes use of the zero-length array language
 extension to the C90 standard, but the preferred mechanism to declare
 variable-length types such as these ones is a flexible array member[1][2],
 introduced in C99:
 
 struct foo {
         int stuff;
         struct boo array[];
 };
 
 By making use of the mechanism above, we will get a compiler warning
 in case the flexible array does not occur last in the structure, which
 will help us prevent some kind of undefined behavior bugs from being
 inadvertently introduced[3] to the codebase from now on.
 
 Also, notice that, dynamic memory allocations won't be affected by
 this change:
 
 "Flexible array members have incomplete type, and so the sizeof operator
 may not be applied. As a quirk of the original implementation of
 zero-length arrays, sizeof evaluates to zero."[1]
 
 sizeof(flexible-array-member) triggers a warning because flexible array
 members have incomplete type[1]. There are some instances of code in
 which the sizeof operator is being incorrectly/erroneously applied to
 zero-length arrays and the result is zero. Such instances may be hiding
 some bugs. So, this work (flexible-array member convertions) will also
 help to get completely rid of those sorts of issues.
 
 Notice that all of these patches have been baking in linux-next for
 quite a while now and, 238 more of these patches have already been
 merged into 5.7-rc1.
 
 There are a couple hundred more of these issues waiting to be addressed
 in the whole codebase.
 
 [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
 [2] https://github.com/KSPP/linux/issues/21
 [3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
 
 Thanks
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Merge tag 'flexible-array-member-5.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

Pull flexible-array member conversion from Gustavo Silva:
 "The current codebase makes use of the zero-length array language
  extension to the C90 standard, but the preferred mechanism to declare
  variable-length types such as these ones is a flexible array
  member[1][2], introduced in C99:

    struct foo {
        int stuff;
        struct boo array[];
    };

  By making use of the mechanism above, we will get a compiler warning
  in case the flexible array does not occur last in the structure, which
  will help us prevent some kind of undefined behavior bugs from being
  inadvertently introduced[3] to the codebase from now on.

  Also, notice that, dynamic memory allocations won't be affected by
  this change:

   "Flexible array members have incomplete type, and so the sizeof
    operator may not be applied. As a quirk of the original
    implementation of zero-length arrays, sizeof evaluates to zero."[1]

  sizeof(flexible-array-member) triggers a warning because flexible
  array members have incomplete type[1]. There are some instances of
  code in which the sizeof operator is being incorrectly/erroneously
  applied to zero-length arrays and the result is zero. Such instances
  may be hiding some bugs. So, this work (flexible-array member
  convertions) will also help to get completely rid of those sorts of
  issues.

  Notice that all of these patches have been baking in linux-next for
  quite a while now and, 238 more of these patches have already been
  merged into 5.7-rc1.

  There are a couple hundred more of these issues waiting to be
  addressed in the whole codebase"

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

* tag 'flexible-array-member-5.7-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux: (28 commits)
  xattr.h: Replace zero-length array with flexible-array member
  uapi: linux: fiemap.h: Replace zero-length array with flexible-array member
  uapi: linux: dlm_device.h: Replace zero-length array with flexible-array member
  tpm_eventlog.h: Replace zero-length array with flexible-array member
  ti_wilink_st.h: Replace zero-length array with flexible-array member
  swap.h: Replace zero-length array with flexible-array member
  skbuff.h: Replace zero-length array with flexible-array member
  sched: topology.h: Replace zero-length array with flexible-array member
  rslib.h: Replace zero-length array with flexible-array member
  rio.h: Replace zero-length array with flexible-array member
  posix_acl.h: Replace zero-length array with flexible-array member
  platform_data: wilco-ec.h: Replace zero-length array with flexible-array member
  memcontrol.h: Replace zero-length array with flexible-array member
  list_lru.h: Replace zero-length array with flexible-array member
  lib: cpu_rmap: Replace zero-length array with flexible-array member
  irq.h: Replace zero-length array with flexible-array member
  ihex.h: Replace zero-length array with flexible-array member
  igmp.h: Replace zero-length array with flexible-array member
  genalloc.h: Replace zero-length array with flexible-array member
  ethtool.h: Replace zero-length array with flexible-array member
  ...
2020-04-19 10:34:30 -07:00
arch - Remove vdso code trying to free unallocated pages. 2020-04-17 10:39:43 -07:00
block blk-wbt: Use tracepoint_string() for wbt_step tracepoint string literals 2020-04-17 08:21:44 -06:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-04-01 14:47:40 -07:00
Documentation hwmon fixes for v5.7-rc2 2020-04-18 13:28:09 -07:00
drivers SCSI fixes on 20200418 2020-04-18 14:03:12 -07:00
fs Fixes for 5.7: 2020-04-18 11:46:39 -07:00
include flexible-array member convertion patches for 5.7-rc2 2020-04-19 10:34:30 -07:00
init Kbuild updates for v5.7 (2nd) 2020-04-11 09:46:12 -07:00
ipc ipc/util.c: sysvipc_find_ipc() should increase position index 2020-04-10 15:36:22 -07:00
kernel for-linus-2020-04-18 2020-04-18 11:38:51 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-04-16 14:52:29 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge branch 'akpm' (patches from Andrew) 2020-04-10 17:57:48 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-04-16 14:52:29 -07:00
samples samples/hw_breakpoint: drop use of kallsyms_lookup_name() 2020-04-07 10:43:44 -07:00
scripts A handful of fixes for reasonably obnoxious documentation issues. 2020-04-17 13:10:50 -07:00
security selinux/stable-5.7 PR 20200416 2020-04-16 10:45:47 -07:00
sound sound fixes for 5.7-rc2 2020-04-17 09:48:50 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-04-16 14:52:29 -07:00
usr kbuild: fix comment about missing include guard detection 2020-04-11 12:09:48 +09:00
virt KVM: Pass kvm_init()'s opaque param to additional arch funcs 2020-03-31 10:48:03 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2020-03-06 21:50:05 +01:00
.cocciconfig
.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 mailmap: Add Sedat Dilek (replacement for expired email address) 2020-04-11 09:28:34 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Hand MIPS over to Thomas 2020-02-24 22:43:18 -08:00
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 SCSI fixes on 20200418 2020-04-18 14:03:12 -07:00
Makefile Linux 5.7-rc1 2020-04-12 12:35:55 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.