linux/drivers/net/wireless/intel/iwlegacy
Gustavo A. R. Silva 8863b1212a iwlegacy: 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>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200507185529.GA14639@embeddedor
2020-05-12 11:54:47 +03:00
..
3945-debug.c
3945-mac.c iwlegacy: Remove unneeded variable ret 2020-03-12 15:41:22 +02:00
3945-rs.c mac80211: populate debugfs only after cfg80211 init 2020-04-24 11:30:13 +02:00
3945.c
3945.h
4965-calib.c
4965-debug.c
4965-mac.c iwlegacy: use <linux/units.h> helpers 2020-01-31 10:30:40 -08:00
4965-rs.c mac80211: populate debugfs only after cfg80211 init 2020-04-24 11:30:13 +02:00
4965.c iwlegacy: Remove unneeded variable ret 2020-03-12 15:41:22 +02:00
4965.h
commands.h iwlegacy: Replace zero-length array with flexible-array 2020-05-12 11:54:47 +03:00
common.c iwlegacy: ensure loop counter addr does not wrap and cause an infinite loop 2020-01-26 17:51:47 +02:00
common.h iwlegacy: use <linux/units.h> helpers 2020-01-31 10:30:40 -08:00
csr.h
debug.c
iwl-spectrum.h iwlegacy: Replace zero-length array with flexible-array 2020-05-12 11:54:47 +03:00
Kconfig
Makefile
prph.h