283 lines
10 KiB
Plaintext
283 lines
10 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 DEBUG_SLAB
|
||
|
|
bool "Debug slab memory allocations"
|
||
|
|
depends on DEBUG_KERNEL && SLAB
|
||
|
|
help
|
||
|
|
Say Y here to have the kernel do limited verification on memory
|
||
|
|
allocation as well as poisoning memory on free to catch use of freed
|
||
|
|
memory. This can make kmalloc/kfree-intensive workloads much slower.
|
||
|
|
|
||
|
|
config SLUB_DEBUG
|
||
|
|
default y
|
||
|
|
bool "Enable SLUB debugging support" if EXPERT
|
||
|
|
depends on SLUB && SYSFS && !SLUB_TINY
|
||
|
|
select STACKDEPOT if STACKTRACE_SUPPORT
|
||
|
|
help
|
||
|
|
SLUB has extensive debug support features. Disabling these can
|
||
|
|
result in significant savings in code size. This also disables
|
||
|
|
SLUB sysfs support. /sys/slab will not exist and there will be
|
||
|
|
no support for cache validation etc.
|
||
|
|
|
||
|
|
config SLUB_DEBUG_ON
|
||
|
|
bool "SLUB debugging on by default"
|
||
|
|
depends on SLUB && SLUB_DEBUG
|
||
|
|
select STACKDEPOT_ALWAYS_INIT if STACKTRACE_SUPPORT
|
||
|
|
default n
|
||
|
|
help
|
||
|
|
Boot with debugging on by default. SLUB boots by default with
|
||
|
|
the runtime debug capabilities switched off. Enabling this is
|
||
|
|
equivalent to specifying the "slub_debug" parameter on boot.
|
||
|
|
There is no support for more fine grained debug control like
|
||
|
|
possible with slub_debug=xxx. SLUB debugging may be switched
|
||
|
|
off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
|
||
|
|
"slub_debug=-".
|
||
|
|
|
||
|
|
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/mm/page_owner_sort.c
|
||
|
|
for user-space helper.
|
||
|
|
|
||
|
|
If unsure, say N.
|
||
|
|
|
||
|
|
config PAGE_TABLE_CHECK
|
||
|
|
bool "Check for invalid mappings in user page tables"
|
||
|
|
depends on ARCH_SUPPORTS_PAGE_TABLE_CHECK
|
||
|
|
depends on EXCLUSIVE_SYSTEM_RAM
|
||
|
|
select PAGE_EXTENSION
|
||
|
|
help
|
||
|
|
Check that anonymous page is not being mapped twice with read write
|
||
|
|
permissions. Check that anonymous and file pages are not being
|
||
|
|
erroneously shared. Since the checking is performed at the time
|
||
|
|
entries are added and removed to user page tables, leaking, corruption
|
||
|
|
and double mapping problems are detected synchronously.
|
||
|
|
|
||
|
|
If unsure say "n".
|
||
|
|
|
||
|
|
config PAGE_TABLE_CHECK_ENFORCED
|
||
|
|
bool "Enforce the page table checking by default"
|
||
|
|
depends on PAGE_TABLE_CHECK
|
||
|
|
help
|
||
|
|
Always enable page table checking. By default the page table checking
|
||
|
|
is disabled, and can be optionally enabled via page_table_check=on
|
||
|
|
kernel parameter. This config enforces that page table check is always
|
||
|
|
enabled.
|
||
|
|
|
||
|
|
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.
|
||
|
|
|
||
|
|
config HAVE_DEBUG_KMEMLEAK
|
||
|
|
bool
|
||
|
|
|
||
|
|
config DEBUG_KMEMLEAK
|
||
|
|
bool "Kernel memory leak detector"
|
||
|
|
depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
|
||
|
|
select DEBUG_FS
|
||
|
|
select STACKTRACE if STACKTRACE_SUPPORT
|
||
|
|
select KALLSYMS
|
||
|
|
select CRC32
|
||
|
|
select STACKDEPOT
|
||
|
|
select STACKDEPOT_ALWAYS_INIT if !DEBUG_KMEMLEAK_DEFAULT_OFF
|
||
|
|
help
|
||
|
|
Say Y here if you want to enable the memory leak
|
||
|
|
detector. The memory allocation/freeing is traced in a way
|
||
|
|
similar to the Boehm's conservative garbage collector, the
|
||
|
|
difference being that the orphan objects are not freed but
|
||
|
|
only shown in /sys/kernel/debug/kmemleak. Enabling this
|
||
|
|
feature will introduce an overhead to memory
|
||
|
|
allocations. See Documentation/dev-tools/kmemleak.rst for more
|
||
|
|
details.
|
||
|
|
|
||
|
|
Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
|
||
|
|
of finding leaks due to the slab objects poisoning.
|
||
|
|
|
||
|
|
In order to access the kmemleak file, debugfs needs to be
|
||
|
|
mounted (usually at /sys/kernel/debug).
|
||
|
|
|
||
|
|
config DEBUG_KMEMLEAK_MEM_POOL_SIZE
|
||
|
|
int "Kmemleak memory pool size"
|
||
|
|
depends on DEBUG_KMEMLEAK
|
||
|
|
range 200 1000000
|
||
|
|
default 16000
|
||
|
|
help
|
||
|
|
Kmemleak must track all the memory allocations to avoid
|
||
|
|
reporting false positives. Since memory may be allocated or
|
||
|
|
freed before kmemleak is fully initialised, use a static pool
|
||
|
|
of metadata objects to track such callbacks. After kmemleak is
|
||
|
|
fully initialised, this memory pool acts as an emergency one
|
||
|
|
if slab allocations fail.
|
||
|
|
|
||
|
|
config DEBUG_KMEMLEAK_TEST
|
||
|
|
tristate "Simple test for the kernel memory leak detector"
|
||
|
|
depends on DEBUG_KMEMLEAK && m
|
||
|
|
help
|
||
|
|
This option enables a module that explicitly leaks memory.
|
||
|
|
|
||
|
|
If unsure, say N.
|
||
|
|
|
||
|
|
config DEBUG_KMEMLEAK_DEFAULT_OFF
|
||
|
|
bool "Default kmemleak to off"
|
||
|
|
depends on DEBUG_KMEMLEAK
|
||
|
|
help
|
||
|
|
Say Y here to disable kmemleak by default. It can then be enabled
|
||
|
|
on the command line via kmemleak=on.
|
||
|
|
|
||
|
|
config DEBUG_KMEMLEAK_AUTO_SCAN
|
||
|
|
bool "Enable kmemleak auto scan thread on boot up"
|
||
|
|
default y
|
||
|
|
depends on DEBUG_KMEMLEAK
|
||
|
|
help
|
||
|
|
Depending on the cpu, kmemleak scan may be cpu intensive and can
|
||
|
|
stall user tasks at times. This option enables/disables automatic
|
||
|
|
kmemleak scan at boot up.
|
||
|
|
|
||
|
|
Say N here to disable kmemleak auto scan thread to stop automatic
|
||
|
|
scanning. Disabling this option disables automatic reporting of
|
||
|
|
memory leaks.
|
||
|
|
|
||
|
|
If unsure, say Y.
|
||
|
|
|