https://github.com/torvalds/linux
Revision e76018cb604ace486de9cf85898c14bb2b47faff authored by Gustavo A. R. Silva on 23 March 2020, 21:48:10 UTC, committed by Gustavo A. R. Silva on 18 April 2020, 20:44:54 UTC
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]

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 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
1 parent 5a58ec8
History
Tip revision: e76018cb604ace486de9cf85898c14bb2b47faff authored by Gustavo A. R. Silva on 23 March 2020, 21:48:10 UTC
can: dev: peak_canfd.h: Replace zero-length array with flexible-array member
Tip revision: e76018c
File Mode Size
Kconfig -rw-r--r-- 722 bytes
Makefile -rw-r--r-- 204 bytes
cfg.c -rw-r--r-- 11.4 KB
cfg.h -rw-r--r-- 202 bytes
driver-ops.h -rw-r--r-- 5.8 KB
ieee802154_i.h -rw-r--r-- 5.0 KB
iface.c -rw-r--r-- 19.0 KB
llsec.c -rw-r--r-- 24.8 KB
llsec.h -rw-r--r-- 2.8 KB
mac_cmd.c -rw-r--r-- 3.8 KB
main.c -rw-r--r-- 5.6 KB
mib.c -rw-r--r-- 5.1 KB
rx.c -rw-r--r-- 7.1 KB
trace.c -rw-r--r-- 189 bytes
trace.h -rw-r--r-- 6.4 KB
tx.c -rw-r--r-- 3.0 KB
util.c -rw-r--r-- 2.3 KB

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