forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
152 lines
5.6 KiB
152 lines
5.6 KiB
# 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" |
|
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 you are only interested in sanitization of freed pages without |
|
checking the poison pattern on alloc, you can boot the kernel with |
|
"init_on_free=1" instead of enabling this. |
|
|
|
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. |
|
|
|
config ARCH_HAS_DEBUG_WX |
|
bool |
|
|
|
config DEBUG_WX |
|
bool "Warn on W+X mappings at boot" |
|
depends on ARCH_HAS_DEBUG_WX |
|
depends on MMU |
|
select PTDUMP_CORE |
|
help |
|
Generate a warning if any W+X mappings are found at boot. |
|
|
|
This is useful for discovering cases where the kernel is leaving W+X |
|
mappings after applying NX, as such mappings are a security risk. |
|
|
|
Look for a message in dmesg output like this: |
|
|
|
<arch>/mm: Checked W+X mappings: passed, no W+X pages found. |
|
|
|
or like this, if the check failed: |
|
|
|
<arch>/mm: Checked W+X mappings: failed, <N> W+X pages found. |
|
|
|
Note that even if the check fails, your kernel is possibly |
|
still fine, as W+X mappings are not a security hole in |
|
themselves, what they do is that they make the exploitation |
|
of other unfixed kernel bugs easier. |
|
|
|
There is no runtime or memory usage effect of this option |
|
once the kernel has booted up - it's a one time check. |
|
|
|
If in doubt, say "Y". |
|
|
|
config GENERIC_PTDUMP |
|
bool |
|
|
|
config PTDUMP_CORE |
|
bool |
|
|
|
config PTDUMP_DEBUGFS |
|
bool "Export kernel pagetable layout to userspace via debugfs" |
|
depends on DEBUG_KERNEL |
|
depends on DEBUG_FS |
|
depends on GENERIC_PTDUMP |
|
select PTDUMP_CORE |
|
help |
|
Say Y here if you want to show the kernel pagetable layout in a |
|
debugfs file. This information is only useful for kernel developers |
|
who are working in architecture specific areas of the kernel. |
|
It is probably not a good idea to enable this feature in a production |
|
kernel. |
|
|
|
If in doubt, say N.
|
|
|