Hi all,
On Fri, 17 May 2024 09:23:47 +1000 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>
> On Fri, 12 Apr 2024 12:04:21 +1000 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
> >
> > Today's linux-next merge of the modules tree got a conflict in:
> >
> > kernel/module/main.c
> >
> > between commit:
> >
> > 58782d7a7ccd ("lib: prevent module unloading if memory is not freed")
> >
> > from the mm-unstable branch of the mm tree and commit:
> >
> > a4ee8c9b86bd ("module: make module_memory_{alloc,free} more self-contained")
> >
> > from the modules tree.
> >
>
> This is now a conflict between the mm-stable tree and Linus' tree.
The actual final resolution (due to more patches) is below.
--
Cheers,
Stephen Rothwell
diff --cc kernel/module/main.c
index 91e185607d4b,2d25eebc549d..d18a94b973e1
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@@ -56,8 -56,8 +56,9 @@@
#include <linux/dynamic_debug.h>
#include <linux/audit.h>
#include <linux/cfi.h>
+ #include <linux/codetag.h>
#include <linux/debugfs.h>
+#include <linux/execmem.h>
#include <uapi/linux/module.h>
#include "internal.h"
@@@ -1188,50 -1198,32 +1189,54 @@@ void __weak module_arch_freeing_init(st
{
}
-static bool mod_mem_use_vmalloc(enum mod_mem_type type)
+static int module_memory_alloc(struct module *mod, enum mod_mem_type type)
{
- return IS_ENABLED(CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC) &&
- mod_mem_type_is_core_data(type);
-}
+ unsigned int size = PAGE_ALIGN(mod->mem[type].size);
+ enum execmem_type execmem_type;
+ void *ptr;
-static void *module_memory_alloc(unsigned int size, enum mod_mem_type type)
-{
- if (mod_mem_use_vmalloc(type))
- return vzalloc(size);
- return module_alloc(size);
+ mod->mem[type].size = size;
+
+ if (mod_mem_type_is_data(type))
+ execmem_type = EXECMEM_MODULE_DATA;
+ else
+ execmem_type = EXECMEM_MODULE_TEXT;
+
+ ptr = execmem_alloc(execmem_type, size);
+ if (!ptr)
+ return -ENOMEM;
+
+ /*
+ * The pointer to these blocks of memory are stored on the module
+ * structure and we keep that around so long as the module is
+ * around. We only free that memory when we unload the module.
+ * Just mark them as not being a leak then. The .init* ELF
+ * sections *do* get freed after boot so we *could* treat them
+ * slightly differently with kmemleak_ignore() and only grey
+ * them out as they work as typical memory allocations which
+ * *do* eventually get freed, but let's just keep things simple
+ * and avoid *any* false positives.
+ */
+ kmemleak_not_leak(ptr);
+
+ memset(ptr, 0, size);
+ mod->mem[type].base = ptr;
+
+ return 0;
}
- static void module_memory_free(struct module *mod, enum mod_mem_type type)
-static void module_memory_free(void *ptr, enum mod_mem_type type,
++static void module_memory_free(struct module *mod, enum mod_mem_type type,
+ bool unload_codetags)
{
+ void *ptr = mod->mem[type].base;
+
+ if (!unload_codetags && mod_mem_type_is_core_data(type))
+ return;
+
- if (mod_mem_use_vmalloc(type))
- vfree(ptr);
- else
- module_memfree(ptr);
+ execmem_free(ptr);
}
- static void free_mod_mem(struct module *mod)
+ static void free_mod_mem(struct module *mod, bool unload_codetags)
{
for_each_mod_mem_type(type) {
struct module_memory *mod_mem = &mod->mem[type];
@@@ -1242,12 -1234,13 +1247,12 @@@
/* Free lock-classes; relies on the preceding sync_rcu(). */
lockdep_free_key_range(mod_mem->base, mod_mem->size);
if (mod_mem->size)
- module_memory_free(mod, type);
- module_memory_free(mod_mem->base, type,
- unload_codetags);
++ module_memory_free(mod, type, unload_codetags);
}
/* MOD_DATA hosts mod, so free it at last */
lockdep_free_key_range(mod->mem[MOD_DATA].base, mod->mem[MOD_DATA].size);
- module_memory_free(mod, MOD_DATA);
- module_memory_free(mod->mem[MOD_DATA].base, MOD_DATA, unload_codetags);
++ module_memory_free(mod, MOD_DATA, unload_codetags);
}
/* Free a module, remove from lists, etc. */
@@@ -2287,7 -2309,7 +2299,7 @@@ static int move_module(struct module *m
return 0;
out_enomem:
for (t--; t >= 0; t--)
- module_memory_free(mod, t);
- module_memory_free(mod->mem[t].base, t, true);
++ module_memory_free(mod, t, true);
return ret;
}
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