+ module-fix-types-of-device-tables-aliases.patch added to -mm tree

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The patch titled
     Subject: module: fix types of device tables aliases
has been added to the -mm tree.  Its filename is
     module-fix-types-of-device-tables-aliases.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/module-fix-types-of-device-tables-aliases.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/module-fix-types-of-device-tables-aliases.patch

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------------------------------------------------------
From: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx>
Subject: module: fix types of device tables aliases

MODULE_DEVICE_TABLE() macro used to create aliases to device tables. 
Normally alias should have the same type as aliased symbol.

Device tables are arrays, so they have 'struct type##_device_id[x]'
types. Alias created by MODULE_DEVICE_TABLE() will have non-array type -
	'struct type##_device_id'.

This inconsistency confuses compiler, it could make a wrong assumption
about variable's size which leads KASan to produce a false positive report
about out of bounds access.

For every global variable compiler calls __asan_register_globals() passing
information about global variable (address, size, size with redzone, name
...) __asan_register_globals() poison symbols redzone to detect possible
out of bounds accesses.

When symbol has an alias __asan_register_globals() will be called as for
symbol so for alias.  Compiler determines size of variable by size of
variable's type.  Alias and symbol have the same address, so if alias have
the wrong size part of memory that actually belongs to the symbol could be
poisoned as redzone of alias symbol.

By fixing type of alias symbol we will fix size of it, so
__asan_register_globals() will not poison valid memory.

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/module.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN include/linux/module.h~module-fix-types-of-device-tables-aliases include/linux/module.h
--- a/include/linux/module.h~module-fix-types-of-device-tables-aliases
+++ a/include/linux/module.h
@@ -135,7 +135,7 @@ void trim_init_extable(struct module *m)
 #ifdef MODULE
 /* Creates an alias so file2alias.c can find device table. */
 #define MODULE_DEVICE_TABLE(type, name)					\
-  extern const struct type##_device_id __mod_##type##__##name##_device_table \
+extern const typeof(name) __mod_##type##__##name##_device_table		\
   __attribute__ ((unused, alias(__stringify(name))))
 #else  /* !MODULE */
 #define MODULE_DEVICE_TABLE(type, name)
_

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

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