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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-09 15:27:15 -0500
committerJan Kara <jack@suse.cz>2020-03-16 15:57:09 +0100
commit3fc131663cec7ca8e05bf25d99cecc2ab56bc50d (patch)
tree94e713eab31cf0359d12e92e52f0301ef76b1e2f /fs/udf
parentc2d0699c629d30dde3329003baac3b94f1d717e6 (diff)
udf: udf_sb.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") Link: https://lore.kernel.org/r/20200309202715.GA9428@embeddedor Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/udf')
-rw-r--r--fs/udf/udf_sb.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
index 3d83be54c474..758efe557a19 100644
--- a/fs/udf/udf_sb.h
+++ b/fs/udf/udf_sb.h
@@ -83,7 +83,7 @@ struct udf_virtual_data {
struct udf_bitmap {
__u32 s_extPosition;
int s_nr_groups;
- struct buffer_head *s_block_bitmap[0];
+ struct buffer_head *s_block_bitmap[];
};
struct udf_part_map {