linux-kernel - linux-next: manual merge of the modules tree with the mm tree

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Message-ID: <20240412120421.27d86c34@canb.auug.org.au>
Date: Fri, 12 Apr 2024 12:04:21 +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 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.

I fixed it up (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,d56b7df0cbb6..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"
  
@@@ -1204,26 -1194,51 +1195,55 @@@ static bool mod_mem_use_vmalloc(enum mo
  		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 = execmem_alloc(EXECMEM_MODULE_TEXT, 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)
++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 -1249,12 +1254,13 @@@
  		/* 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);
++			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 -2301,7 +2314,7 @@@ 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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