The patch titled
Subject: mm: vmalloc: add flag preventing guard hole allocation
has been added to the -mm tree. Its filename is
mm-vmalloc-add-flag-preventing-guard-hole-allocation.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-vmalloc-add-flag-preventing-guard-hole-allocation.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-vmalloc-add-flag-preventing-guard-hole-allocation.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx>
Subject: mm: vmalloc: add flag preventing guard hole allocation
For instrumenting global variables KASan will shadow memory backing memory
for modules. So on module loading we will need to allocate memory for
shadow and map it at address in shadow that corresponds to the address
allocated in module_alloc().
__vmalloc_node_range() could be used for this purpose, except it puts a
guard hole after allocated area. Guard hole in shadow memory should be a
problem because at some future point we might need to have a shadow memory
at address occupied by guard hole. So we could fail to allocate shadow
for module_alloc().
Add a new vm_struct flag 'VM_NO_GUARD' indicating that vm area doesn't
have a guard hole.
Signed-off-by: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Konstantin Serebryany <kcc@xxxxxxxxxx>
Cc: Dmitry Chernenkov <dmitryc@xxxxxxxxxx>
Cc: Andrey Konovalov <adech.fo@xxxxxxxxx>
Cc: Yuri Gribov <tetra2005@xxxxxxxxx>
Cc: Konstantin Khlebnikov <koct9i@xxxxxxxxx>
Cc: Sasha Levin <sasha.levin@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/vmalloc.h | 9 +++++++--
mm/vmalloc.c | 6 ++----
2 files changed, 9 insertions(+), 6 deletions(-)
diff -puN include/linux/vmalloc.h~mm-vmalloc-add-flag-preventing-guard-hole-allocation include/linux/vmalloc.h
--- a/include/linux/vmalloc.h~mm-vmalloc-add-flag-preventing-guard-hole-allocation
+++ a/include/linux/vmalloc.h
@@ -16,6 +16,7 @@ struct vm_area_struct; /* vma defining
#define VM_USERMAP 0x00000008 /* suitable for remap_vmalloc_range */
#define VM_VPAGES 0x00000010 /* buffer for pages was vmalloc'ed */
#define VM_UNINITIALIZED 0x00000020 /* vm_struct is not fully initialized */
+#define VM_NO_GUARD 0x00000040 /* don't add guard page */
/* bits [20..32] reserved for arch specific ioremap internals */
/*
@@ -96,8 +97,12 @@ void vmalloc_sync_all(void);
static inline size_t get_vm_area_size(const struct vm_struct *area)
{
- /* return actual size without guard page */
- return area->size - PAGE_SIZE;
+ if (!(area->flags & VM_NO_GUARD))
+ /* return actual size without guard page */
+ return area->size - PAGE_SIZE;
+ else
+ return area->size;
+
}
extern struct vm_struct *get_vm_area(unsigned long size, unsigned long flags);
diff -puN mm/vmalloc.c~mm-vmalloc-add-flag-preventing-guard-hole-allocation mm/vmalloc.c
--- a/mm/vmalloc.c~mm-vmalloc-add-flag-preventing-guard-hole-allocation
+++ a/mm/vmalloc.c
@@ -1324,10 +1324,8 @@ static struct vm_struct *__get_vm_area_n
if (unlikely(!area))
return NULL;
- /*
- * We always allocate a guard page.
- */
- size += PAGE_SIZE;
+ if (!(flags & VM_NO_GUARD))
+ size += PAGE_SIZE;
va = alloc_vmap_area(size, align, start, end, node, gfp_mask);
if (IS_ERR(va)) {
_
Patches currently in -mm which might be from a.ryabinin@xxxxxxxxxxx are
compiler-introduce-__aliassymbol-shortcut.patch
add-kernel-address-sanitizer-infrastructure.patch
kasan-disable-memory-hotplug.patch
x86_64-add-kasan-support.patch
mm-page_alloc-add-kasan-hooks-on-alloc-and-free-paths.patch
mm-slub-introduce-virt_to_obj-function.patch
mm-slub-share-object_err-function.patch
mm-slub-introduce-metadata_access_enable-metadata_access_disable.patch
mm-slub-add-kernel-address-sanitizer-support-for-slub-allocator.patch
fs-dcache-manually-unpoison-dname-after-allocation-to-shut-up-kasans-reports.patch
kmemleak-disable-kasan-instrumentation-for-kmemleak.patch
lib-add-kasan-test-module.patch
x86_64-kasan-add-interceptors-for-memset-memmove-memcpy-functions.patch
kasan-enable-stack-instrumentation.patch
mm-vmalloc-add-flag-preventing-guard-hole-allocation.patch
mm-vmalloc-pass-additional-vm_flags-to-__vmalloc_node_range.patch
kernel-add-support-for-init_array-constructors.patch
module-fix-types-of-device-tables-aliases.patch
kasan-enable-instrumentation-of-global-variables.patch
hugetlb-sysctl-pass-extra1-=-null-rather-then-extra1-=-zero.patch
mm-hugetlb-fix-type-of-hugetlb_treat_as_movable-variable.patch
proc-pagemap-walk-page-tables-under-pte-lock.patch
linux-next.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
