mm, page_owner: decouple freeing stack trace from debug_pagealloc
Commit 8974558f49
("mm, page_owner, debug_pagealloc: save and dump
freeing stack trace") enhanced page_owner to also store freeing stack
trace, when debug_pagealloc is also enabled. KASAN would also like to
do this [1] to improve error reports to debug e.g. UAF issues.
Kirill has suggested that the freeing stack trace saving should be also
possible to be enabled separately from KASAN or debug_pagealloc, i.e.
with an extra boot option. Qian argued that we have enough options
already, and avoiding the extra overhead is not worth the complications
in the case of a debugging option. Kirill noted that the extra stack
handle in struct page_owner requires 0.1% of memory.
This patch therefore enables free stack saving whenever page_owner is
enabled, regardless of whether debug_pagealloc or KASAN is also enabled.
KASAN kernels booted with page_owner=on will thus benefit from the
improved error reports.
[1] https://bugzilla.kernel.org/show_bug.cgi?id=203967
[vbabka@suse.cz: v3]
Link: http://lkml.kernel.org/r/20191007091808.7096-3-vbabka@suse.cz
Link: http://lkml.kernel.org/r/20190930122916.14969-3-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Qian Cai <cai@lca.pw>
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Suggested-by: Walter Wu <walter-zh.wu@mediatek.com>
Suggested-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Suggested-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
alistair/sunxi64-5.4-dsi
parent
5556cfe8d9
commit
0fe9a448a0
|
@ -41,6 +41,9 @@ smaller binary while the latter is 1.1 - 2 times faster.
|
||||||
Both KASAN modes work with both SLUB and SLAB memory allocators.
|
Both KASAN modes work with both SLUB and SLAB memory allocators.
|
||||||
For better bug detection and nicer reporting, enable CONFIG_STACKTRACE.
|
For better bug detection and nicer reporting, enable CONFIG_STACKTRACE.
|
||||||
|
|
||||||
|
To augment reports with last allocation and freeing stack of the physical page,
|
||||||
|
it is recommended to enable also CONFIG_PAGE_OWNER and boot with page_owner=on.
|
||||||
|
|
||||||
To disable instrumentation for specific files or directories, add a line
|
To disable instrumentation for specific files or directories, add a line
|
||||||
similar to the following to the respective kernel Makefile:
|
similar to the following to the respective kernel Makefile:
|
||||||
|
|
||||||
|
|
|
@ -24,12 +24,10 @@ struct page_owner {
|
||||||
short last_migrate_reason;
|
short last_migrate_reason;
|
||||||
gfp_t gfp_mask;
|
gfp_t gfp_mask;
|
||||||
depot_stack_handle_t handle;
|
depot_stack_handle_t handle;
|
||||||
#ifdef CONFIG_DEBUG_PAGEALLOC
|
|
||||||
depot_stack_handle_t free_handle;
|
depot_stack_handle_t free_handle;
|
||||||
#endif
|
|
||||||
};
|
};
|
||||||
|
|
||||||
static bool page_owner_disabled = true;
|
static bool page_owner_enabled = false;
|
||||||
DEFINE_STATIC_KEY_FALSE(page_owner_inited);
|
DEFINE_STATIC_KEY_FALSE(page_owner_inited);
|
||||||
|
|
||||||
static depot_stack_handle_t dummy_handle;
|
static depot_stack_handle_t dummy_handle;
|
||||||
|
@ -44,7 +42,7 @@ static int __init early_page_owner_param(char *buf)
|
||||||
return -EINVAL;
|
return -EINVAL;
|
||||||
|
|
||||||
if (strcmp(buf, "on") == 0)
|
if (strcmp(buf, "on") == 0)
|
||||||
page_owner_disabled = false;
|
page_owner_enabled = true;
|
||||||
|
|
||||||
return 0;
|
return 0;
|
||||||
}
|
}
|
||||||
|
@ -52,10 +50,7 @@ early_param("page_owner", early_page_owner_param);
|
||||||
|
|
||||||
static bool need_page_owner(void)
|
static bool need_page_owner(void)
|
||||||
{
|
{
|
||||||
if (page_owner_disabled)
|
return page_owner_enabled;
|
||||||
return false;
|
|
||||||
|
|
||||||
return true;
|
|
||||||
}
|
}
|
||||||
|
|
||||||
static __always_inline depot_stack_handle_t create_dummy_stack(void)
|
static __always_inline depot_stack_handle_t create_dummy_stack(void)
|
||||||
|
@ -84,7 +79,7 @@ static noinline void register_early_stack(void)
|
||||||
|
|
||||||
static void init_page_owner(void)
|
static void init_page_owner(void)
|
||||||
{
|
{
|
||||||
if (page_owner_disabled)
|
if (!page_owner_enabled)
|
||||||
return;
|
return;
|
||||||
|
|
||||||
register_dummy_stack();
|
register_dummy_stack();
|
||||||
|
@ -148,25 +143,18 @@ void __reset_page_owner(struct page *page, unsigned int order)
|
||||||
{
|
{
|
||||||
int i;
|
int i;
|
||||||
struct page_ext *page_ext;
|
struct page_ext *page_ext;
|
||||||
#ifdef CONFIG_DEBUG_PAGEALLOC
|
|
||||||
depot_stack_handle_t handle = 0;
|
depot_stack_handle_t handle = 0;
|
||||||
struct page_owner *page_owner;
|
struct page_owner *page_owner;
|
||||||
|
|
||||||
if (debug_pagealloc_enabled())
|
|
||||||
handle = save_stack(GFP_NOWAIT | __GFP_NOWARN);
|
handle = save_stack(GFP_NOWAIT | __GFP_NOWARN);
|
||||||
#endif
|
|
||||||
|
|
||||||
page_ext = lookup_page_ext(page);
|
page_ext = lookup_page_ext(page);
|
||||||
if (unlikely(!page_ext))
|
if (unlikely(!page_ext))
|
||||||
return;
|
return;
|
||||||
for (i = 0; i < (1 << order); i++) {
|
for (i = 0; i < (1 << order); i++) {
|
||||||
__clear_bit(PAGE_EXT_OWNER_ACTIVE, &page_ext->flags);
|
__clear_bit(PAGE_EXT_OWNER_ACTIVE, &page_ext->flags);
|
||||||
#ifdef CONFIG_DEBUG_PAGEALLOC
|
|
||||||
if (debug_pagealloc_enabled()) {
|
|
||||||
page_owner = get_page_owner(page_ext);
|
page_owner = get_page_owner(page_ext);
|
||||||
page_owner->free_handle = handle;
|
page_owner->free_handle = handle;
|
||||||
}
|
|
||||||
#endif
|
|
||||||
page_ext = page_ext_next(page_ext);
|
page_ext = page_ext_next(page_ext);
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
@ -450,7 +438,6 @@ void __dump_page_owner(struct page *page)
|
||||||
stack_trace_print(entries, nr_entries, 0);
|
stack_trace_print(entries, nr_entries, 0);
|
||||||
}
|
}
|
||||||
|
|
||||||
#ifdef CONFIG_DEBUG_PAGEALLOC
|
|
||||||
handle = READ_ONCE(page_owner->free_handle);
|
handle = READ_ONCE(page_owner->free_handle);
|
||||||
if (!handle) {
|
if (!handle) {
|
||||||
pr_alert("page_owner free stack trace missing\n");
|
pr_alert("page_owner free stack trace missing\n");
|
||||||
|
@ -459,7 +446,6 @@ void __dump_page_owner(struct page *page)
|
||||||
pr_alert("page last free stack trace:\n");
|
pr_alert("page last free stack trace:\n");
|
||||||
stack_trace_print(entries, nr_entries, 0);
|
stack_trace_print(entries, nr_entries, 0);
|
||||||
}
|
}
|
||||||
#endif
|
|
||||||
|
|
||||||
if (page_owner->last_migrate_reason != -1)
|
if (page_owner->last_migrate_reason != -1)
|
||||||
pr_alert("page has been migrated, last migrate reason: %s\n",
|
pr_alert("page has been migrated, last migrate reason: %s\n",
|
||||||
|
|
Loading…
Reference in New Issue