tree 28b9e34473ebb996455d572f55e8d6ffe72a3cb1
parent 50cc09c18985eacbbd666acfd7be2391394733f5
parent 43951585e1308b322c8ee31a4aafd08213f5c5d7
author Linus Torvalds <torvalds@linux-foundation.org> 1587317670 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1587317670 -0700
mergetag object 43951585e1308b322c8ee31a4aafd08213f5c5d7
 type commit
 tag flexible-array-member-5.7-rc2
 tagger Gustavo A. R. Silva <gustavo@embeddedor.com> 1587244233 -0500
 
 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 76497732932f ("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 76497732932f ("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
  ...