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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-13 09:14:09 -0600 |
|---|---|---|
| committer | Jessica Yu <jeyu@kernel.org> | 2020-02-17 21:40:55 +0100 |
| commit | 0f74226649fb2875a91b68f3750f55220aa73425 (patch) | |
| tree | 15d0a05e66b5234736e898284fde95f1b2324c78 /kernel/module.c | |
| parent | bb6d3fb354c5ee8d6bde2d576eb7220ea09862b9 (diff) | |
| download | linux-0f74226649fb2875a91b68f3750f55220aa73425.tar.gz linux-0f74226649fb2875a91b68f3750f55220aa73425.tar.bz2 linux-0f74226649fb2875a91b68f3750f55220aa73425.zip | |
kernel: module: 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: Jessica Yu <jeyu@kernel.org>
Diffstat (limited to 'kernel/module.c')
| -rw-r--r-- | kernel/module.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/module.c b/kernel/module.c index 33569a01d6e1..b88ec9cd2a7f 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1515,7 +1515,7 @@ struct module_sect_attr { struct module_sect_attrs { struct attribute_group grp; unsigned int nsections; - struct module_sect_attr attrs[0]; + struct module_sect_attr attrs[]; }; static ssize_t module_sect_show(struct module_attribute *mattr, @@ -1608,7 +1608,7 @@ static void remove_sect_attrs(struct module *mod) struct module_notes_attrs { struct kobject *dir; unsigned int notes; - struct bin_attribute attrs[0]; + struct bin_attribute attrs[]; }; static ssize_t module_notes_read(struct file *filp, struct kobject *kobj, |