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authorMasahiro Yamada <yamada.masahiro@socionext.com>2019-10-03 10:58:21 +0300
committerJessica Yu <jeyu@kernel.org>2019-10-07 19:24:48 +0300
commitbf70b0503abd19194dba25fe383d143d0229dc6a (patch)
treea1560c25488553e750ca04152719a1b9d5abaff7 /scripts
parentc7c4e29fb5a422fd144b3fb0d3e32375d8f9b0ba (diff)
downloadlinux-bf70b0503abd19194dba25fe383d143d0229dc6a.tar.xz
module: swap the order of symbol.namespace
Currently, EXPORT_SYMBOL_NS(_GPL) constructs the kernel symbol as follows: __ksymtab_SYMBOL.NAMESPACE The sym_extract_namespace() in modpost allocates memory for the part SYMBOL.NAMESPACE when '.' is contained. One problem is that the pointer returned by strdup() is lost because the symbol name will be copied to malloc'ed memory by alloc_symbol(). No one will keep track of the pointer of strdup'ed memory. sym->namespace still points to the NAMESPACE part. So, you can free it with complicated code like this: free(sym->namespace - strlen(sym->name) - 1); It complicates memory free. To fix it elegantly, I swapped the order of the symbol and the namespace as follows: __ksymtab_NAMESPACE.SYMBOL then, simplified sym_extract_namespace() so that it allocates memory only for the NAMESPACE part. I prefer this order because it is intuitive and also matches to major languages. For example, NAMESPACE::NAME in C++, MODULE.NAME in Python. Reviewed-by: Matthias Maennich <maennich@google.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Jessica Yu <jeyu@kernel.org>
Diffstat (limited to 'scripts')
-rw-r--r--scripts/mod/modpost.c16
1 files changed, 7 insertions, 9 deletions
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 3961941e8e7a..c4b536ac1327 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -350,18 +350,16 @@ static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
static const char *sym_extract_namespace(const char **symname)
{
- size_t n;
- char *dupsymname;
+ char *namespace = NULL;
+ char *ns_separator;
- n = strcspn(*symname, ".");
- if (n < strlen(*symname) - 1) {
- dupsymname = NOFAIL(strdup(*symname));
- dupsymname[n] = '\0';
- *symname = dupsymname;
- return dupsymname + n + 1;
+ ns_separator = strchr(*symname, '.');
+ if (ns_separator) {
+ namespace = NOFAIL(strndup(*symname, ns_separator - *symname));
+ *symname = ns_separator + 1;
}
- return NULL;
+ return namespace;
}
/**