The patch titled
Subject: alloc_tag: avoid execmem_vmap() when !MMU
has been added to the -mm mm-unstable branch. Its filename is
alloc_tag-populate-memory-for-module-tags-as-needed-fix.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/alloc_tag-populate-memory-for-module-tags-as-needed-fix.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Subject: alloc_tag: avoid execmem_vmap() when !MMU
Date: Mon, 28 Oct 2024 13:29:35 -0700
With CONFIG_MMU=n __get_vm_area_node() is not available and memory for the
allocation tags cannot be populated as needed. For this case, populate
the required memory at initialization time.
Link: https://lkml.kernel.org/r/20241028202935.1047017-1-surenb@xxxxxxxxxx
Fixes: 57bc3834fb6f ("alloc_tag: populate memory for module tags as needed")
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202410250808.dQGyYjlk-lkp@xxxxxxxxx/
Closes: https://lore.kernel.org/oe-lkp/202410251525.9f85854d-oliver.sang@xxxxxxxxx
Closes: https://lore.kernel.org/oe-kbuild-all/202410261016.IO7C6Cml-lkp@xxxxxxxxx/
Closes: https://lore.kernel.org/oe-kbuild-all/202410270919.LebQlmxD-lkp@xxxxxxxxx/
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Cc: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Song Liu <song@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/execmem.h | 2 ++
lib/alloc_tag.c | 23 ++++++++++++++++++++++-
mm/execmem.c | 32 ++++++++++++++++----------------
3 files changed, 40 insertions(+), 17 deletions(-)
--- a/include/linux/execmem.h~alloc_tag-populate-memory-for-module-tags-as-needed-fix
+++ a/include/linux/execmem.h
@@ -139,6 +139,7 @@ void *execmem_alloc(enum execmem_type ty
*/
void execmem_free(void *ptr);
+#ifdef CONFIG_MMU
/**
* execmem_vmap - create virtual mapping for EXECMEM_MODULE_DATA memory
* @size: size of the virtual mapping in bytes
@@ -148,6 +149,7 @@ void execmem_free(void *ptr);
* Return: the area descriptor on success or %NULL on failure.
*/
struct vm_struct *execmem_vmap(size_t size);
+#endif
/**
* execmem_update_copy - copy an update to executable memory
--- a/lib/alloc_tag.c~alloc_tag-populate-memory-for-module-tags-as-needed-fix
+++ a/lib/alloc_tag.c
@@ -180,7 +180,6 @@ static void __init procfs_init(void)
#ifdef CONFIG_MODULES
static struct maple_tree mod_area_mt = MTREE_INIT(mod_area_mt, MT_FLAGS_ALLOC_RANGE);
-static struct vm_struct *vm_module_tags;
/* A dummy object used to indicate an unloaded module */
static struct module unloaded_mod;
/* A dummy object used to indicate a module prepended area */
@@ -254,6 +253,9 @@ repeat:
return false;
}
+#ifdef CONFIG_MMU
+static struct vm_struct *vm_module_tags;
+
static int vm_module_tags_populate(void)
{
unsigned long phys_size = vm_module_tags->nr_pages << PAGE_SHIFT;
@@ -280,6 +282,13 @@ static int vm_module_tags_populate(void)
return 0;
}
+#else
+static int vm_module_tags_populate(void)
+{
+ /* Memory was already allocated */
+ return 0;
+}
+#endif
static void *reserve_module_tags(struct module *mod, unsigned long size,
unsigned int prepend, unsigned long align)
@@ -411,6 +420,7 @@ static void replace_module(struct module
static int __init alloc_mod_tags_mem(void)
{
+#ifdef CONFIG_MMU
/* Map space to copy allocation tags */
vm_module_tags = execmem_vmap(MODULE_ALLOC_TAG_VMAP_SIZE);
if (!vm_module_tags) {
@@ -428,6 +438,13 @@ static int __init alloc_mod_tags_mem(voi
}
module_tags.start_addr = (unsigned long)vm_module_tags->addr;
+#else
+ /* Allocate space to copy allocation tags */
+ module_tags.start_addr = (unsigned long)execmem_alloc(EXECMEM_MODULE_DATA,
+ MODULE_ALLOC_TAG_VMAP_SIZE);
+ if (!module_tags.start_addr)
+ return -ENOMEM;
+#endif
module_tags.end_addr = module_tags.start_addr + MODULE_ALLOC_TAG_VMAP_SIZE;
return 0;
@@ -435,6 +452,7 @@ static int __init alloc_mod_tags_mem(voi
static void __init free_mod_tags_mem(void)
{
+#ifdef CONFIG_MMU
int i;
module_tags.start_addr = 0;
@@ -442,6 +460,9 @@ static void __init free_mod_tags_mem(voi
__free_page(vm_module_tags->pages[i]);
kfree(vm_module_tags->pages);
free_vm_area(vm_module_tags);
+#else
+ execmem_free((void *)module_tags.start_addr);
+#endif
}
#else /* CONFIG_MODULES */
--- a/mm/execmem.c~alloc_tag-populate-memory-for-module-tags-as-needed-fix
+++ a/mm/execmem.c
@@ -64,6 +64,22 @@ static void *execmem_vmalloc(struct exec
return p;
}
+
+struct vm_struct *execmem_vmap(size_t size)
+{
+ struct execmem_range *range = &execmem_info->ranges[EXECMEM_MODULE_DATA];
+ struct vm_struct *area;
+
+ area = __get_vm_area_node(size, range->alignment, PAGE_SHIFT, VM_ALLOC,
+ range->start, range->end, NUMA_NO_NODE,
+ GFP_KERNEL, __builtin_return_address(0));
+ if (!area && range->fallback_start)
+ area = __get_vm_area_node(size, range->alignment, PAGE_SHIFT, VM_ALLOC,
+ range->fallback_start, range->fallback_end,
+ NUMA_NO_NODE, GFP_KERNEL, __builtin_return_address(0));
+
+ return area;
+}
#else
static void *execmem_vmalloc(struct execmem_range *range, size_t size,
pgprot_t pgprot, unsigned long vm_flags)
@@ -368,22 +384,6 @@ void execmem_free(void *ptr)
vfree(ptr);
}
-struct vm_struct *execmem_vmap(size_t size)
-{
- struct execmem_range *range = &execmem_info->ranges[EXECMEM_MODULE_DATA];
- struct vm_struct *area;
-
- area = __get_vm_area_node(size, range->alignment, PAGE_SHIFT, VM_ALLOC,
- range->start, range->end, NUMA_NO_NODE,
- GFP_KERNEL, __builtin_return_address(0));
- if (!area && range->fallback_start)
- area = __get_vm_area_node(size, range->alignment, PAGE_SHIFT, VM_ALLOC,
- range->fallback_start, range->fallback_end,
- NUMA_NO_NODE, GFP_KERNEL, __builtin_return_address(0));
-
- return area;
-}
-
void *execmem_update_copy(void *dst, const void *src, size_t size)
{
return text_poke_copy(dst, src, size);
_
Patches currently in -mm which might be from surenb@xxxxxxxxxx are
maple_tree-add-mas_for_each_rev-helper.patch
alloc_tag-introduce-shutdown_mem_profiling-helper-function.patch
alloc_tag-load-module-tags-into-separate-contiguous-memory.patch
alloc_tag-populate-memory-for-module-tags-as-needed.patch
alloc_tag-populate-memory-for-module-tags-as-needed-fix.patch
alloc_tag-introduce-pgtag_ref_handle-to-abstract-page-tag-references.patch
alloc_tag-support-for-page-allocation-tag-compression.patch
mm-convert-mm_lock_seq-to-a-proper-seqcount.patch
mm-introduce-mmap_lock_speculation_beginend.patch
mm-codetag-uninline-and-move-pgalloc_tag_copy-and-pgalloc_tag_split.patch
