* [PATCH] lib/ts_fsm: Replace zero-length array with flexible-array member
@ 2020-02-11 20:58 Gustavo A. R. Silva
0 siblings, 0 replies; only message in thread
From: Gustavo A. R. Silva @ 2020-02-11 20:58 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-kernel, Gustavo A. R. Silva
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
inadvertenly introduced[3] to the codebase from now on.
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>
---
lib/ts_fsm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/ts_fsm.c b/lib/ts_fsm.c
index 69557c74ef9f..f7aed7b6f3fe 100644
--- a/lib/ts_fsm.c
+++ b/lib/ts_fsm.c
@@ -36,7 +36,7 @@
struct ts_fsm
{
unsigned int ntokens;
- struct ts_fsm_token tokens[0];
+ struct ts_fsm_token tokens[];
};
/* other values derived from ctype.h */
--
2.25.0
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