Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
index 9a7b8b0..327b3eb 100644
--- a/mm/Kconfig.debug
+++ b/mm/Kconfig.debug
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
config PAGE_EXTENSION
bool "Extend memmap on extra space for more information on page"
---help---
@@ -11,19 +12,25 @@
bool "Debug page memory allocations"
depends on DEBUG_KERNEL
depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC
- select PAGE_EXTENSION
select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC
---help---
Unmap pages from the kernel linear mapping after free_pages().
Depending on runtime enablement, this results in a small or large
slowdown, but helps to find certain types of memory corruption.
+ Also, the state of page tracking structures is checked more often as
+ pages are being allocated and freed, as unexpected state changes
+ often happen for same reasons as memory corruption (e.g. double free,
+ use-after-free). The error reports for these checks can be augmented
+ with stack traces of last allocation and freeing of the page, when
+ PAGE_OWNER is also selected and enabled on boot.
+
For architectures which don't enable ARCH_SUPPORTS_DEBUG_PAGEALLOC,
fill the pages with poison patterns after free_pages() and verify
- the patterns before alloc_pages(). Additionally,
- this option cannot be enabled in combination with hibernation as
- that would result in incorrect warnings of memory corruption after
- a resume because free pages are not saved to the suspend image.
+ the patterns before alloc_pages(). Additionally, this option cannot
+ be enabled in combination with hibernation as that would result in
+ incorrect warnings of memory corruption after a resume because free
+ pages are not saved to the suspend image.
By default this option will have a small overhead, e.g. by not
allowing the kernel mapping to be backed by large pages on some
@@ -33,12 +40,28 @@
config DEBUG_PAGEALLOC_ENABLE_DEFAULT
bool "Enable debug page memory allocations by default?"
- default n
depends on DEBUG_PAGEALLOC
---help---
Enable debug page memory allocations by default? This value
can be overridden by debug_pagealloc=off|on.
+config PAGE_OWNER
+ bool "Track page owner"
+ depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
+ select DEBUG_FS
+ select STACKTRACE
+ select STACKDEPOT
+ select PAGE_EXTENSION
+ help
+ This keeps track of what call chain is the owner of a page, may
+ help to find bare alloc_page(s) leaks. Even if you include this
+ feature on your build, it is disabled in default. You should pass
+ "page_owner=on" to boot parameter in order to enable it. Eats
+ a fair amount of memory if enabled. See tools/vm/page_owner_sort.c
+ for user-space helper.
+
+ If unsure, say N.
+
config PAGE_POISONING
bool "Poison pages after freeing"
select PAGE_POISONING_NO_SANITY if HIBERNATION