modules: don't hand 0 to vmalloc.
In commit d0a21265dfb5fa8a David Rientjes unified various archs'
module_alloc implementation (including x86) and removed the graduitous
shortcut for size == 0.
Then, in commit de7d2b567d040e3b, Joe Perches added a warning for
zero-length vmallocs, which can happen without kallsyms on modules
with no init sections (eg. zlib_deflate).
Fix this once and for all; the module code has to handle zero length
anyway, so get it right at the caller and remove the now-gratuitous
checks within the arch-specific module_alloc implementations.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=42608
Reported-by: Conrad Kostecki <ConiKost@gmx.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/kernel/module.c b/kernel/module.c
index 79a526d..4542ff3 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2377,7 +2377,7 @@
void * __weak module_alloc(unsigned long size)
{
- return size == 0 ? NULL : vmalloc_exec(size);
+ return vmalloc_exec(size);
}
static void *module_alloc_update_bounds(unsigned long size)
@@ -2793,20 +2793,23 @@
memset(ptr, 0, mod->core_size);
mod->module_core = ptr;
- ptr = module_alloc_update_bounds(mod->init_size);
- /*
- * The pointer to this block is stored in the module structure
- * which is inside the block. This block doesn't need to be
- * scanned as it contains data and code that will be freed
- * after the module is initialized.
- */
- kmemleak_ignore(ptr);
- if (!ptr && mod->init_size) {
- module_free(mod, mod->module_core);
- return -ENOMEM;
- }
- memset(ptr, 0, mod->init_size);
- mod->module_init = ptr;
+ if (mod->init_size) {
+ ptr = module_alloc_update_bounds(mod->init_size);
+ /*
+ * The pointer to this block is stored in the module structure
+ * which is inside the block. This block doesn't need to be
+ * scanned as it contains data and code that will be freed
+ * after the module is initialized.
+ */
+ kmemleak_ignore(ptr);
+ if (!ptr) {
+ module_free(mod, mod->module_core);
+ return -ENOMEM;
+ }
+ memset(ptr, 0, mod->init_size);
+ mod->module_init = ptr;
+ } else
+ mod->module_init = NULL;
/* Transfer each section which specifies SHF_ALLOC */
pr_debug("final section addresses:\n");