mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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a7f7f6248d
Since commit 84af7a6194 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.
This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.
There are a variety of indentation styles found.
a) 4 spaces + '---help---'
b) 7 spaces + '---help---'
c) 8 spaces + '---help---'
d) 1 space + 1 tab + '---help---'
e) 1 tab + '---help---' (correct indentation)
f) 1 tab + 1 space + '---help---'
g) 1 tab + 2 spaces + '---help---'
In order to convert all of them to 1 tab + 'help', I ran the
following commend:
$ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
172 lines
6.2 KiB
Text
172 lines
6.2 KiB
Text
# SPDX-License-Identifier: GPL-2.0-only
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config PAGE_EXTENSION
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bool "Extend memmap on extra space for more information on page"
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help
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Extend memmap on extra space for more information on page. This
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could be used for debugging features that need to insert extra
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field for every page. This extension enables us to save memory
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by not allocating this extra memory according to boottime
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configuration.
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config DEBUG_PAGEALLOC
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bool "Debug page memory allocations"
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depends on DEBUG_KERNEL
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depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC
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select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC
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help
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Unmap pages from the kernel linear mapping after free_pages().
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Depending on runtime enablement, this results in a small or large
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slowdown, but helps to find certain types of memory corruption.
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Also, the state of page tracking structures is checked more often as
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pages are being allocated and freed, as unexpected state changes
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often happen for same reasons as memory corruption (e.g. double free,
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use-after-free). The error reports for these checks can be augmented
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with stack traces of last allocation and freeing of the page, when
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PAGE_OWNER is also selected and enabled on boot.
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For architectures which don't enable ARCH_SUPPORTS_DEBUG_PAGEALLOC,
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fill the pages with poison patterns after free_pages() and verify
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the patterns before alloc_pages(). Additionally, this option cannot
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be enabled in combination with hibernation as that would result in
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incorrect warnings of memory corruption after a resume because free
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pages are not saved to the suspend image.
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By default this option will have a small overhead, e.g. by not
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allowing the kernel mapping to be backed by large pages on some
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architectures. Even bigger overhead comes when the debugging is
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enabled by DEBUG_PAGEALLOC_ENABLE_DEFAULT or the debug_pagealloc
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command line parameter.
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config DEBUG_PAGEALLOC_ENABLE_DEFAULT
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bool "Enable debug page memory allocations by default?"
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depends on DEBUG_PAGEALLOC
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help
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Enable debug page memory allocations by default? This value
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can be overridden by debug_pagealloc=off|on.
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config PAGE_OWNER
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bool "Track page owner"
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depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
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select DEBUG_FS
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select STACKTRACE
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select STACKDEPOT
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select PAGE_EXTENSION
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help
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This keeps track of what call chain is the owner of a page, may
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help to find bare alloc_page(s) leaks. Even if you include this
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feature on your build, it is disabled in default. You should pass
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"page_owner=on" to boot parameter in order to enable it. Eats
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a fair amount of memory if enabled. See tools/vm/page_owner_sort.c
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for user-space helper.
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If unsure, say N.
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config PAGE_POISONING
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bool "Poison pages after freeing"
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select PAGE_POISONING_NO_SANITY if HIBERNATION
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help
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Fill the pages with poison patterns after free_pages() and verify
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the patterns before alloc_pages. The filling of the memory helps
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reduce the risk of information leaks from freed data. This does
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have a potential performance impact if enabled with the
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"page_poison=1" kernel boot option.
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Note that "poison" here is not the same thing as the "HWPoison"
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for CONFIG_MEMORY_FAILURE. This is software poisoning only.
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If unsure, say N
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config PAGE_POISONING_NO_SANITY
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depends on PAGE_POISONING
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bool "Only poison, don't sanity check"
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help
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Skip the sanity checking on alloc, only fill the pages with
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poison on free. This reduces some of the overhead of the
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poisoning feature.
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If you are only interested in sanitization, say Y. Otherwise
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say N.
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config PAGE_POISONING_ZERO
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bool "Use zero for poisoning instead of debugging value"
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depends on PAGE_POISONING
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help
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Instead of using the existing poison value, fill the pages with
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zeros. This makes it harder to detect when errors are occurring
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due to sanitization but the zeroing at free means that it is
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no longer necessary to write zeros when GFP_ZERO is used on
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allocation.
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If unsure, say N
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config DEBUG_PAGE_REF
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bool "Enable tracepoint to track down page reference manipulation"
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depends on DEBUG_KERNEL
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depends on TRACEPOINTS
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help
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This is a feature to add tracepoint for tracking down page reference
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manipulation. This tracking is useful to diagnose functional failure
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due to migration failures caused by page reference mismatches. Be
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careful when enabling this feature because it adds about 30 KB to the
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kernel code. However the runtime performance overhead is virtually
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nil until the tracepoints are actually enabled.
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config DEBUG_RODATA_TEST
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bool "Testcase for the marking rodata read-only"
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depends on STRICT_KERNEL_RWX
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help
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This option enables a testcase for the setting rodata read-only.
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config ARCH_HAS_DEBUG_WX
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bool
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config DEBUG_WX
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bool "Warn on W+X mappings at boot"
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depends on ARCH_HAS_DEBUG_WX
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depends on MMU
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select PTDUMP_CORE
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help
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Generate a warning if any W+X mappings are found at boot.
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This is useful for discovering cases where the kernel is leaving W+X
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mappings after applying NX, as such mappings are a security risk.
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Look for a message in dmesg output like this:
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<arch>/mm: Checked W+X mappings: passed, no W+X pages found.
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or like this, if the check failed:
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<arch>/mm: Checked W+X mappings: failed, <N> W+X pages found.
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Note that even if the check fails, your kernel is possibly
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still fine, as W+X mappings are not a security hole in
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themselves, what they do is that they make the exploitation
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of other unfixed kernel bugs easier.
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There is no runtime or memory usage effect of this option
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once the kernel has booted up - it's a one time check.
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If in doubt, say "Y".
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config GENERIC_PTDUMP
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bool
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config PTDUMP_CORE
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bool
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config PTDUMP_DEBUGFS
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bool "Export kernel pagetable layout to userspace via debugfs"
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depends on DEBUG_KERNEL
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depends on DEBUG_FS
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depends on GENERIC_PTDUMP
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select PTDUMP_CORE
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help
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Say Y here if you want to show the kernel pagetable layout in a
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debugfs file. This information is only useful for kernel developers
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who are working in architecture specific areas of the kernel.
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It is probably not a good idea to enable this feature in a production
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kernel.
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If in doubt, say N.
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