120 lines
4.7 KiB
Plaintext
120 lines
4.7 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
|
|
config PAGE_EXTENSION
|
|
bool "Extend memmap on extra space for more information on page"
|
|
---help---
|
|
Extend memmap on extra space for more information on page. This
|
|
could be used for debugging features that need to insert extra
|
|
field for every page. This extension enables us to save memory
|
|
by not allocating this extra memory according to boottime
|
|
configuration.
|
|
|
|
config DEBUG_PAGEALLOC
|
|
bool "Debug page memory allocations"
|
|
depends on DEBUG_KERNEL
|
|
depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC
|
|
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.
|
|
|
|
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
|
|
architectures. Even bigger overhead comes when the debugging is
|
|
enabled by DEBUG_PAGEALLOC_ENABLE_DEFAULT or the debug_pagealloc
|
|
command line parameter.
|
|
|
|
config DEBUG_PAGEALLOC_ENABLE_DEFAULT
|
|
bool "Enable debug page memory allocations by default?"
|
|
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
|
|
---help---
|
|
Fill the pages with poison patterns after free_pages() and verify
|
|
the patterns before alloc_pages. The filling of the memory helps
|
|
reduce the risk of information leaks from freed data. This does
|
|
have a potential performance impact if enabled with the
|
|
"page_poison=1" kernel boot option.
|
|
|
|
Note that "poison" here is not the same thing as the "HWPoison"
|
|
for CONFIG_MEMORY_FAILURE. This is software poisoning only.
|
|
|
|
If unsure, say N
|
|
|
|
config PAGE_POISONING_NO_SANITY
|
|
depends on PAGE_POISONING
|
|
bool "Only poison, don't sanity check"
|
|
---help---
|
|
Skip the sanity checking on alloc, only fill the pages with
|
|
poison on free. This reduces some of the overhead of the
|
|
poisoning feature.
|
|
|
|
If you are only interested in sanitization, say Y. Otherwise
|
|
say N.
|
|
|
|
config PAGE_POISONING_ZERO
|
|
bool "Use zero for poisoning instead of debugging value"
|
|
depends on PAGE_POISONING
|
|
---help---
|
|
Instead of using the existing poison value, fill the pages with
|
|
zeros. This makes it harder to detect when errors are occurring
|
|
due to sanitization but the zeroing at free means that it is
|
|
no longer necessary to write zeros when GFP_ZERO is used on
|
|
allocation.
|
|
|
|
If unsure, say N
|
|
|
|
config DEBUG_PAGE_REF
|
|
bool "Enable tracepoint to track down page reference manipulation"
|
|
depends on DEBUG_KERNEL
|
|
depends on TRACEPOINTS
|
|
---help---
|
|
This is a feature to add tracepoint for tracking down page reference
|
|
manipulation. This tracking is useful to diagnose functional failure
|
|
due to migration failures caused by page reference mismatches. Be
|
|
careful when enabling this feature because it adds about 30 KB to the
|
|
kernel code. However the runtime performance overhead is virtually
|
|
nil until the tracepoints are actually enabled.
|
|
|
|
config DEBUG_RODATA_TEST
|
|
bool "Testcase for the marking rodata read-only"
|
|
depends on STRICT_KERNEL_RWX
|
|
---help---
|
|
This option enables a testcase for the setting rodata read-only.
|