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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-03-09 15:27:15 -0500 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2020-03-16 15:57:09 +0100 |
| commit | 3fc131663cec7ca8e05bf25d99cecc2ab56bc50d (patch) | |
| tree | 94e713eab31cf0359d12e92e52f0301ef76b1e2f /fs/udf | |
| parent | c2d0699c629d30dde3329003baac3b94f1d717e6 (diff) | |
| download | linux-3fc131663cec7ca8e05bf25d99cecc2ab56bc50d.tar.gz | |
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.h | 2 |
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 { |