From 3381df0954199458fa3993db72fb427f0ed1e43b Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Thu, 21 May 2020 13:57:07 -0500 Subject: 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 Link: https://lore.kernel.org/r/20200521185707.GA3661@embeddedor Signed-off-by: Geert Uytterhoeven --- arch/m68k/tools/amiga/dmesg.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/m68k/tools/amiga') 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[]; }; -- cgit v1.2.3