Date: Wed, 24 Apr 2024 12:39:35 +1000
From: Stephen Rothwell <sfr@...b.auug.org.au>
To: Luis Chamberlain <mcgrof@...nel.org>, Andrew Morton
 <akpm@...ux-foundation.org>
Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, Linux Next
 Mailing List <linux-next@...r.kernel.org>, "Mike Rapoport (IBM)"
 <rppt@...nel.org>, Suren Baghdasaryan <surenb@...gle.com>
Subject: linux-next: manual merge of the modules tree with the mm tree

Hi all,

Today's linux-next merge of the modules tree got a conflict in:

  kernel/module/main.c

between commits:

  7f014cdda4cb ("lib: code tagging module support")
  5ab9b0c7ea5c ("lib: prevent module unloading if memory is not freed")

from the mm-unstable branch of the mm tree and commits:

  0746f9982603 ("module: make module_memory_{alloc,free} more self-contained")
  18da532eefc8 ("mm/execmem, arch: convert remaining overrides of module_alloc to execmem")

from the modules tree.

I fixed it up (I think, see below) and can carry the fix as
necessary. This is now fixed as far as linux-next is concerned, but any
non trivial conflicts should be mentioned to your upstream maintainer
when your tree is submitted for merging.  You may also want to consider
cooperating with the maintainer of the conflicting tree to minimise any
particularly complex conflicts.

-- 
Cheers,
Stephen Rothwell

diff --cc kernel/module/main.c
index 2d25eebc549d,91e185607d4b..000000000000
--- 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"
  
@@@ -1198,32 -1188,50 +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;
+ 
+ 	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_alloc(unsigned int size, enum mod_mem_type type)
- {
- 	if (mod_mem_use_vmalloc(type))
- 		return vzalloc(size);
- 	return module_alloc(size);
- }
- 
- 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)
++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];
@@@ -1234,13 -1242,12 +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_mem->base, type,
- 					   unload_codetags);
 -			module_memory_free(mod, type);
++			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->mem[MOD_DATA].base, MOD_DATA, unload_codetags);
 -	module_memory_free(mod, MOD_DATA);
++	module_memory_free(mod, MOD_DATA, unload_codetags);
  }
  
  /* Free a module, remove from lists, etc. */
@@@ -2309,7 -2287,7 +2299,7 @@@ static int move_module(struct module *m
  	return 0;
  out_enomem:
  	for (t--; t >= 0; t--)
- 		module_memory_free(mod->mem[t].base, t, true);
 -		module_memory_free(mod, t);
++		module_memory_free(mod, t, true);
  	return ret;
  }
  

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