linux/include
Gustavo A. R. Silva 3c23215ba8 mac80211: Replace zero-length array with flexible-array
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 conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[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")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200507185907.GA15102@embeddedor
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2020-05-27 10:02:04 +02:00
..
acpi Additional ACPI updates for 5.7-rc1 2020-04-06 10:35:06 -07:00
asm-generic arch: split MODULE_ARCH_VERMAGIC definitions out to <asm/vermagic.h> 2020-04-23 10:50:26 +09:00
clocksource
crypto crypto: curve25519 - do not pollute dispatcher based on assembler 2020-04-09 00:01:59 +09:00
drm drm: fix trivial field description cut-and-paste error 2020-05-11 10:48:53 -07:00
dt-bindings RISC-V Patches for the 5.7 Merge Window, Part 1 2020-04-09 10:51:30 -07:00
keys
kunit
kvm
linux cfg80211: Replace zero-length array with flexible-array 2020-05-27 10:02:03 +02:00
math-emu
media
misc
net mac80211: Replace zero-length array with flexible-array 2020-05-27 10:02:04 +02:00
pcmcia
ras
rdma
scsi SCSI misc on 20200402 2020-04-02 17:03:53 -07:00
soc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-05-06 22:10:13 -07:00
sound ALSA: rawmidi: Fix racy buffer resize under concurrent accesses 2020-05-07 22:29:14 +02:00
target
trace Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-05-24 13:47:27 -07:00
uapi nl80211: support scan frequencies in KHz 2020-05-27 10:02:03 +02:00
vdso vdso/datapage: Use correct clock mode name in comment 2020-04-20 19:19:52 +02:00
video
xen xen: Use evtchn_type_t as a type for event channels 2020-04-07 12:12:54 +02:00