The patch titled
Subject: mm-security-introduce-init_on_alloc=1-and-init_on_free=1-boot-options-v9
has been added to the -mm tree. Its filename is
mm-security-introduce-init_on_alloc=1-and-init_on_free=1-boot-options-v9.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-security-introduce-init_on_alloc%3D1-and-init_on_free%3D1-boot-options-v9.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-security-introduce-init_on_alloc%3D1-and-init_on_free%3D1-boot-options-v9.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Alexander Potapenko <glider@xxxxxxxxxx>
Subject: mm-security-introduce-init_on_alloc=1-and-init_on_free=1-boot-options-v9
- picked up -mm fixes from Qian Cai and Andrew Morton (order of calls
in free_pages_prepare(), export init_on_alloc)
- exported init_on_free
- allowed using init_on_alloc/init_on_free with SLUB poisoning and
page poisoning. Poisoning supersedes zero-initialization, so some
tests may behave differently with poisoning enabled.
Link: http://lkml.kernel.org/r/20190627130316.254309-2-glider@xxxxxxxxxx
Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 6 ++++--
mm/page_alloc.c | 18 +++++++++---------
mm/slab.h | 5 +++--
mm/slub.c | 4 +---
4 files changed, 17 insertions(+), 16 deletions(-)
--- a/include/linux/mm.h~mm-security-introduce-init_on_alloc=1-and-init_on_free=1-boot-options-v9
+++ a/include/linux/mm.h
@@ -2685,7 +2685,8 @@ DECLARE_STATIC_KEY_FALSE(init_on_alloc);
#endif
static inline bool want_init_on_alloc(gfp_t flags)
{
- if (static_branch_unlikely(&init_on_alloc))
+ if (static_branch_unlikely(&init_on_alloc) &&
+ !page_poisoning_enabled())
return true;
return flags & __GFP_ZERO;
}
@@ -2697,7 +2698,8 @@ DECLARE_STATIC_KEY_FALSE(init_on_free);
#endif
static inline bool want_init_on_free(void)
{
- return static_branch_unlikely(&init_on_free);
+ return static_branch_unlikely(&init_on_free) &&
+ !page_poisoning_enabled();
}
#ifdef CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT
--- a/mm/page_alloc.c~mm-security-introduce-init_on_alloc=1-and-init_on_free=1-boot-options-v9
+++ a/mm/page_alloc.c
@@ -140,11 +140,14 @@ DEFINE_STATIC_KEY_TRUE(init_on_alloc);
#else
DEFINE_STATIC_KEY_FALSE(init_on_alloc);
#endif
+EXPORT_SYMBOL(init_on_alloc);
+
#ifdef CONFIG_INIT_ON_FREE_DEFAULT_ON
DEFINE_STATIC_KEY_TRUE(init_on_free);
#else
DEFINE_STATIC_KEY_FALSE(init_on_free);
#endif
+EXPORT_SYMBOL(init_on_free);
static int __init early_init_on_alloc(char *buf)
{
@@ -154,10 +157,8 @@ static int __init early_init_on_alloc(ch
if (!buf)
return -EINVAL;
ret = kstrtobool(buf, &bool_result);
- if (bool_result && IS_ENABLED(CONFIG_PAGE_POISONING)) {
- pr_warn("mem auto-init: Disabling init_on_alloc: CONFIG_PAGE_POISONING is on\n");
- bool_result = false;
- }
+ if (bool_result && IS_ENABLED(CONFIG_PAGE_POISONING))
+ pr_warn("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_alloc\n");
if (bool_result)
static_branch_enable(&init_on_alloc);
else
@@ -174,10 +175,8 @@ static int __init early_init_on_free(cha
if (!buf)
return -EINVAL;
ret = kstrtobool(buf, &bool_result);
- if (bool_result && IS_ENABLED(CONFIG_PAGE_POISONING)) {
- pr_warn("mem auto-init: Disabling init_on_free: CONFIG_PAGE_POISONING is on\n");
- bool_result = false;
- }
+ if (bool_result && IS_ENABLED(CONFIG_PAGE_POISONING))
+ pr_warn("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_free\n");
if (bool_result)
static_branch_enable(&init_on_free);
else
@@ -1179,9 +1178,10 @@ static __always_inline bool free_pages_p
PAGE_SIZE << order);
}
arch_free_page(page, order);
- kernel_poison_pages(page, 1 << order, 0);
if (want_init_on_free())
kernel_init_free_pages(page, 1 << order);
+
+ kernel_poison_pages(page, 1 << order, 0);
if (debug_pagealloc_enabled())
kernel_map_pages(page, 1 << order, 0);
--- a/mm/slab.h~mm-security-introduce-init_on_alloc=1-and-init_on_free=1-boot-options-v9
+++ a/mm/slab.h
@@ -612,7 +612,7 @@ static inline bool slab_want_init_on_all
if (static_branch_unlikely(&init_on_alloc)) {
if (c->ctor)
return false;
- if (c->flags & SLAB_TYPESAFE_BY_RCU)
+ if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))
return flags & __GFP_ZERO;
return true;
}
@@ -622,7 +622,8 @@ static inline bool slab_want_init_on_all
static inline bool slab_want_init_on_free(struct kmem_cache *c)
{
if (static_branch_unlikely(&init_on_free))
- return !(c->ctor || (c->flags & SLAB_TYPESAFE_BY_RCU));
+ return !(c->ctor ||
+ (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)));
return false;
}
--- a/mm/slub.c~mm-security-introduce-init_on_alloc=1-and-init_on_free=1-boot-options-v9
+++ a/mm/slub.c
@@ -1282,9 +1282,7 @@ out:
if ((static_branch_unlikely(&init_on_alloc) ||
static_branch_unlikely(&init_on_free)) &&
(slub_debug & SLAB_POISON)) {
- pr_warn("mem auto-init: Disabling init_on_alloc/init_on_free: can't be used together with SLAB_POISON\n");
- static_branch_disable(&init_on_alloc);
- static_branch_disable(&init_on_free);
+ pr_warn("mem auto-init: SLAB_POISON will take precedence over init_on_alloc/init_on_free\n");
}
return 1;
}
_
Patches currently in -mm which might be from glider@xxxxxxxxxx are
mm-security-introduce-init_on_alloc=1-and-init_on_free=1-boot-options.patch
mm-security-introduce-init_on_alloc=1-and-init_on_free=1-boot-options-v8.patch
mm-security-introduce-init_on_alloc=1-and-init_on_free=1-boot-options-v9.patch
mm-init-report-memory-auto-initialization-features-at-boot-time.patch
lib-introduce-test_meminit-module.patch
lib-test_meminitc-minor-test-fixes.patch
