kernel_optimize_test/sound/core/oss
Gustavo A. R. Silva 9ad06ebb9a ALSA: 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/20200507192223.GA16335@embeddedor
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2020-05-07 22:30:36 +02:00
..
copy.c
io.c
linear.c ALSA: pcm: oss: Avoid potential buffer overflows 2019-12-04 15:51:30 +01:00
Makefile
mixer_oss.c ALSA: oss: More constifications 2020-01-05 16:14:58 +01:00
mulaw.c ALSA: pcm: oss: Avoid potential buffer overflows 2019-12-04 15:51:30 +01:00
pcm_oss.c ALSA: pcm: oss: Unlock mutex temporarily for sleeping at read/write 2020-02-14 18:17:13 +01:00
pcm_plugin.c ALSA: pcm: oss: Fix regression by buffer overflow fix (again) 2020-04-03 09:38:50 +02:00
pcm_plugin.h ALSA: Replace zero-length array with flexible-array 2020-05-07 22:30:36 +02:00
rate.c ALSA: core: Replace zero-length array with flexible-array member 2020-02-12 08:14:43 +01:00
route.c ALSA: pcm: oss: Avoid potential buffer overflows 2019-12-04 15:51:30 +01:00