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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-19 17:44:35 -0500
committerRichard Weinberger <richard@nod.at>2020-03-30 23:02:37 +0200
commit3676f32a98cd6ed4481c21bceb8b4829d4b6d1cf (patch)
tree31130fa5062fb0c89e63c04e8c7a7bd1cca5fd92 /drivers/mtd/ubi
parentacc5af3efa303d5f36cc8c0f61716161f6ca1384 (diff)
downloadlinux-3676f32a98cd6ed4481c21bceb8b4829d4b6d1cf.tar.bz2
ubi: ubi-media.h: 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 <gustavo@embeddedor.com> Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'drivers/mtd/ubi')
-rw-r--r--drivers/mtd/ubi/ubi-media.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/mtd/ubi/ubi-media.h b/drivers/mtd/ubi/ubi-media.h
index b5fe8f82281b..386db0598e95 100644
--- a/drivers/mtd/ubi/ubi-media.h
+++ b/drivers/mtd/ubi/ubi-media.h
@@ -498,6 +498,6 @@ struct ubi_fm_volhdr {
struct ubi_fm_eba {
__be32 magic;
__be32 reserved_pebs;
- __be32 pnum[0];
+ __be32 pnum[];
} __packed;
#endif /* !__UBI_MEDIA_H__ */