Re: [PATCH RESEND v8 05/16] module: make module_memory_{alloc,free} more self-contained

Masami Hiramatsu
2024-05-07T23:41:13Z

On Sun, 5 May 2024 19:06:17 +0300
Mike Rapoport <rppt@kernel.org> wrote:

> From: "Mike Rapoport (IBM)" <rppt@kernel.org>
>
> Move the logic related to the memory allocation and freeing into
> module_memory_alloc() and module_memory_free().
>

Looks good to me.

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thanks,

> Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
> kernel/module/main.c | 64 +++++++++++++++++++++++++++-----------------
> 1 file changed, 39 insertions(+), 25 deletions(-)
>
> diff --git a/kernel/module/main.c b/kernel/module/main.c
> index e1e8a7a9d6c1..5b82b069e0d3 100644
> --- a/kernel/module/main.c
> +++ b/kernel/module/main.c
> @@ -1203,15 +1203,44 @@ static bool mod_mem_use_vmalloc(enum mod_mem_type type)
> mod_mem_type_is_core_data(type);
> }
>
> -static void *module_memory_alloc(unsigned int size, enum mod_mem_type type)
> +static int module_memory_alloc(struct module *mod, enum mod_mem_type type)
> {
> + unsigned int size = PAGE_ALIGN(mod->mem[type].size);
> + void *ptr;
> +
> + mod->mem[type].size = size;
> +
> if (mod_mem_use_vmalloc(type))
> - return vzalloc(size);
> - return module_alloc(size);
> + ptr = vmalloc(size);
> + else
> + ptr = module_alloc(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(void *ptr, enum mod_mem_type type)
> +static void module_memory_free(struct module *mod, enum mod_mem_type type)
> {
> + void *ptr = mod->mem[type].base;
> +
> if (mod_mem_use_vmalloc(type))
> vfree(ptr);
> else
> @@ -1229,12 +1258,12 @@ static void free_mod_mem(struct module *mod)
> /* 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_mem->base, type);
> + module_memory_free(mod, type);
> }
>
> /* 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->mem[MOD_DATA].base, MOD_DATA);
> + module_memory_free(mod, MOD_DATA);
> }
>
> /* Free a module, remove from lists, etc. */
> @@ -2225,7 +2254,6 @@ static int find_module_sections(struct module *mod, struct load_info *info)
> static int move_module(struct module *mod, struct load_info *info)
> {
> int i;
> - void *ptr;
> enum mod_mem_type t = 0;
> int ret = -ENOMEM;
>
> @@ -2234,26 +2262,12 @@ static int move_module(struct module *mod, struct load_info *info)
> mod->mem[type].base = NULL;
> continue;
> }
> - mod->mem[type].size = PAGE_ALIGN(mod->mem[type].size);
> - ptr = module_memory_alloc(mod->mem[type].size, type);
> - /*
> - * 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);
> - if (!ptr) {
> +
> + ret = module_memory_alloc(mod, type);
> + if (ret) {
> t = type;
> goto out_enomem;
> }
> - memset(ptr, 0, mod->mem[type].size);
> - mod->mem[type].base = ptr;
> }
>
> /* Transfer each section which specifies SHF_ALLOC */
> @@ -2296,7 +2310,7 @@ static int move_module(struct module *mod, struct load_info *info)
> return 0;
> out_enomem:
> for (t--; t >= 0; t--)
> - module_memory_free(mod->mem[t].base, t);
> + module_memory_free(mod, t);
> return ret;
> }
>
> --
> 2.43.0
>

--
Masami Hiramatsu (Google) <mhiramat@kernel.org>