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| -rw-r--r-- | mm/Kconfig.debug | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug new file mode 100644 index 000000000..9a7b8b049 --- /dev/null +++ b/mm/Kconfig.debug @@ -0,0 +1,96 @@ +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_EXTENSION + 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. + + 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?" + default n + depends on DEBUG_PAGEALLOC + ---help--- + Enable debug page memory allocations by default? This value + can be overridden by debug_pagealloc=off|on. + +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. |