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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-13 09:14:09 -0600
committerJessica Yu <jeyu@kernel.org>2020-02-17 21:40:55 +0100
commit0f74226649fb2875a91b68f3750f55220aa73425 (patch)
tree15d0a05e66b5234736e898284fde95f1b2324c78 /kernel/module.c
parentbb6d3fb354c5ee8d6bde2d576eb7220ea09862b9 (diff)
downloadlinux-0f74226649fb2875a91b68f3750f55220aa73425.tar.bz2
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.c4
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,