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author | Gustavo A. R. Silva <gustavoars@kernel.org> | 2020-05-21 13:57:07 -0500 |
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committer | Geert Uytterhoeven <geert@linux-m68k.org> | 2020-05-25 10:55:56 +0200 |
commit | 3381df0954199458fa3993db72fb427f0ed1e43b (patch) | |
tree | 59af751ac0fc295222cc2311cd68f498d9ddd4d5 /arch | |
parent | 2941a4731fd24d5e43ef437cca90818f87fd4851 (diff) | |
download | linux-3381df0954199458fa3993db72fb427f0ed1e43b.tar.gz linux-3381df0954199458fa3993db72fb427f0ed1e43b.tar.bz2 linux-3381df0954199458fa3993db72fb427f0ed1e43b.zip |
m68k: tools: Replace zero-length array with flexible-array member
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 <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200521185707.GA3661@embeddedor
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/m68k/tools/amiga/dmesg.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/m68k/tools/amiga/dmesg.c b/arch/m68k/tools/amiga/dmesg.c index 7340f5b6cf6d..f8005a7efb0b 100644 --- a/arch/m68k/tools/amiga/dmesg.c +++ b/arch/m68k/tools/amiga/dmesg.c @@ -34,7 +34,7 @@ struct savekmsg { u_long magic2; /* SAVEKMSG_MAGIC2 */ u_long magicptr; /* address of magic1 */ u_long size; - char data[0]; + char data[]; }; |