fb23f8fa6a
When allocating higher order pages, currently only the head page is set with page owner info, leaving the tail pages with previous or stale info. This patch sets the info for tail pages too and sets the time of free in page owner info of all pages during free. This patch also adds an extra info to page extension flags to help check if page is in buddy or not. Change-Id: I96d13485af698d586a4dd7b1092a379a645c8fcb Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org> [cgoldswo@codeaurora.org: Fix merge conflicts, add GKI #ifdef guards] Signed-off-by: Chris Goldsworthy <cgoldswo@codeaurora.org>
168 lines
6.5 KiB
Plaintext
168 lines
6.5 KiB
Plaintext
# 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 PAGE_EXTENSION_PAGE_FREE
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bool "Add a flag in page_ext_flags to indicate if a page is free"
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depends on PAGE_EXTENSION && QGKI
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help
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Add the PAGE_FREE flag in page_ext_flags, in order to indicate
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whether a page from the buddy allocator is free or is in
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use. This information can aid in debugging buddy allocator
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related issues.
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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 SLUB_DEBUG_PANIC_ON
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bool "Enable to Panic on SLUB corruption detection"
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depends on SLUB_DEBUG
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help
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SLUB has a resiliency feature enabled which restores bytes in
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order for production environments to continue to operate. IN
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debug options this may not be desirable as it prevents from
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investigating the root cause which may be rooted within cache
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or memory.
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config DEBUG_PANIC_ON_OOM
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bool "Enable to Panic on OOM detection"
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help
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Android primarily uses an alternative mechanism to detect low
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memory situations and kill processes as required. The kernel
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oom-killer can mask problems with this feature, which may be
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undesireable in a debug environment.
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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_OWNER_ENABLE_DEFAULT
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bool "Enable Track page owner by default"
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depends on PAGE_OWNER
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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. If you include this
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feature on your build, it is enabled by default. You should pass
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"page_owner=off" to boot parameter in order to disable 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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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_ENABLE_DEFAULT
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bool "Enable page poisoning by default?"
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default n
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depends on PAGE_POISONING
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help
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Enable page poisoning of free pages by default? This value
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can be overridden by page_poison=off|on. This can be used
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to avoid passing the kernel parameter and let page poisoning
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feature enabled by default.
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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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