Joonsoo Kim | eefa864b | 2014-12-12 16:55:46 -0800 | [diff] [blame] | 1 | config PAGE_EXTENSION |
| 2 | bool "Extend memmap on extra space for more information on page" |
| 3 | ---help--- |
| 4 | Extend memmap on extra space for more information on page. This |
| 5 | could be used for debugging features that need to insert extra |
| 6 | field for every page. This extension enables us to save memory |
| 7 | by not allocating this extra memory according to boottime |
| 8 | configuration. |
| 9 | |
Akinobu Mita | ee3b429 | 2009-04-02 16:56:30 -0700 | [diff] [blame] | 10 | config DEBUG_PAGEALLOC |
| 11 | bool "Debug page memory allocations" |
Akinobu Mita | 7bc32f6 | 2011-03-22 16:32:46 -0700 | [diff] [blame] | 12 | depends on DEBUG_KERNEL |
| 13 | depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC |
Joonsoo Kim | e30825f | 2014-12-12 16:55:49 -0800 | [diff] [blame] | 14 | select PAGE_EXTENSION |
Akinobu Mita | 7bc32f6 | 2011-03-22 16:32:46 -0700 | [diff] [blame] | 15 | select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC |
Akinobu Mita | ee3b429 | 2009-04-02 16:56:30 -0700 | [diff] [blame] | 16 | ---help--- |
| 17 | Unmap pages from the kernel linear mapping after free_pages(). |
Christian Borntraeger | ea6eabb | 2016-03-15 14:55:30 -0700 | [diff] [blame] | 18 | Depending on runtime enablement, this results in a small or large |
| 19 | slowdown, but helps to find certain types of memory corruption. |
Akinobu Mita | ee3b429 | 2009-04-02 16:56:30 -0700 | [diff] [blame] | 20 | |
Akinobu Mita | 7bc32f6 | 2011-03-22 16:32:46 -0700 | [diff] [blame] | 21 | For architectures which don't enable ARCH_SUPPORTS_DEBUG_PAGEALLOC, |
| 22 | fill the pages with poison patterns after free_pages() and verify |
| 23 | the patterns before alloc_pages(). Additionally, |
| 24 | this option cannot be enabled in combination with hibernation as |
| 25 | that would result in incorrect warnings of memory corruption after |
| 26 | a resume because free pages are not saved to the suspend image. |
| 27 | |
Christian Borntraeger | ea6eabb | 2016-03-15 14:55:30 -0700 | [diff] [blame] | 28 | By default this option will have a small overhead, e.g. by not |
| 29 | allowing the kernel mapping to be backed by large pages on some |
| 30 | architectures. Even bigger overhead comes when the debugging is |
| 31 | enabled by DEBUG_PAGEALLOC_ENABLE_DEFAULT or the debug_pagealloc |
| 32 | command line parameter. |
| 33 | |
Channagoud Kadabi | a84bbf9 | 2017-03-15 14:26:08 -0700 | [diff] [blame] | 34 | config SLUB_DEBUG_PANIC_ON |
| 35 | bool "Enable to Panic on SLUB corruption detection" |
| 36 | depends on SLUB_DEBUG |
| 37 | help |
| 38 | SLUB has a resiliency feature enabled which restores bytes in |
| 39 | order for production environments to continue to operate. IN |
| 40 | debug options this may not be desirable as it prevents from |
| 41 | investigating the root cause which may be rooted within cache |
| 42 | or memory. |
| 43 | |
Patrick Daly | e46816d | 2019-05-08 16:10:43 -0700 | [diff] [blame] | 44 | config DEBUG_PANIC_ON_OOM |
| 45 | bool "Enable to Panic on OOM detection" |
| 46 | help |
| 47 | Android primarily uses an alternative mechanism to detect low |
| 48 | memory situations and kill processes as required. The kernel |
| 49 | oom-killer can mask problems with this feature, which may be |
| 50 | undesireable in a debug environment. |
| 51 | |
Christian Borntraeger | ea6eabb | 2016-03-15 14:55:30 -0700 | [diff] [blame] | 52 | config DEBUG_PAGEALLOC_ENABLE_DEFAULT |
| 53 | bool "Enable debug page memory allocations by default?" |
| 54 | default n |
| 55 | depends on DEBUG_PAGEALLOC |
| 56 | ---help--- |
| 57 | Enable debug page memory allocations by default? This value |
| 58 | can be overridden by debug_pagealloc=off|on. |
| 59 | |
Akinobu Mita | 6a11f75 | 2009-03-31 15:23:17 -0700 | [diff] [blame] | 60 | config PAGE_POISONING |
Laura Abbott | 8823b1d | 2016-03-15 14:56:27 -0700 | [diff] [blame] | 61 | bool "Poison pages after freeing" |
Laura Abbott | 8823b1d | 2016-03-15 14:56:27 -0700 | [diff] [blame] | 62 | select PAGE_POISONING_NO_SANITY if HIBERNATION |
| 63 | ---help--- |
| 64 | Fill the pages with poison patterns after free_pages() and verify |
| 65 | the patterns before alloc_pages. The filling of the memory helps |
| 66 | reduce the risk of information leaks from freed data. This does |
Kees Cook | 8c9a134 | 2018-08-21 21:53:10 -0700 | [diff] [blame] | 67 | have a potential performance impact if enabled with the |
| 68 | "page_poison=1" kernel boot option. |
Laura Abbott | 8823b1d | 2016-03-15 14:56:27 -0700 | [diff] [blame] | 69 | |
| 70 | Note that "poison" here is not the same thing as the "HWPoison" |
| 71 | for CONFIG_MEMORY_FAILURE. This is software poisoning only. |
| 72 | |
| 73 | If unsure, say N |
| 74 | |
Vinayak Menon | 766b261 | 2017-04-05 10:49:14 +0530 | [diff] [blame] | 75 | config PAGE_POISONING_ENABLE_DEFAULT |
| 76 | bool "Enable page poisoning by default?" |
| 77 | default n |
| 78 | depends on PAGE_POISONING |
| 79 | help |
| 80 | Enable page poisoning of free pages by default? This value |
| 81 | can be overridden by page_poison=off|on. This can be used |
| 82 | to avoid passing the kernel parameter and let page poisoning |
| 83 | feature enabled by default. |
| 84 | |
Laura Abbott | 8823b1d | 2016-03-15 14:56:27 -0700 | [diff] [blame] | 85 | config PAGE_POISONING_NO_SANITY |
| 86 | depends on PAGE_POISONING |
| 87 | bool "Only poison, don't sanity check" |
| 88 | ---help--- |
| 89 | Skip the sanity checking on alloc, only fill the pages with |
| 90 | poison on free. This reduces some of the overhead of the |
| 91 | poisoning feature. |
| 92 | |
| 93 | If you are only interested in sanitization, say Y. Otherwise |
| 94 | say N. |
Laura Abbott | 1414c7f | 2016-03-15 14:56:30 -0700 | [diff] [blame] | 95 | |
| 96 | config PAGE_POISONING_ZERO |
Kees Cook | 8c9a134 | 2018-08-21 21:53:10 -0700 | [diff] [blame] | 97 | bool "Use zero for poisoning instead of debugging value" |
Laura Abbott | 1414c7f | 2016-03-15 14:56:30 -0700 | [diff] [blame] | 98 | depends on PAGE_POISONING |
| 99 | ---help--- |
| 100 | Instead of using the existing poison value, fill the pages with |
| 101 | zeros. This makes it harder to detect when errors are occurring |
| 102 | due to sanitization but the zeroing at free means that it is |
| 103 | no longer necessary to write zeros when GFP_ZERO is used on |
| 104 | allocation. |
| 105 | |
Laura Abbott | 1414c7f | 2016-03-15 14:56:30 -0700 | [diff] [blame] | 106 | If unsure, say N |
Joonsoo Kim | 95813b8 | 2016-03-17 14:19:29 -0700 | [diff] [blame] | 107 | |
| 108 | config DEBUG_PAGE_REF |
| 109 | bool "Enable tracepoint to track down page reference manipulation" |
| 110 | depends on DEBUG_KERNEL |
| 111 | depends on TRACEPOINTS |
| 112 | ---help--- |
| 113 | This is a feature to add tracepoint for tracking down page reference |
| 114 | manipulation. This tracking is useful to diagnose functional failure |
| 115 | due to migration failures caused by page reference mismatches. Be |
| 116 | careful when enabling this feature because it adds about 30 KB to the |
| 117 | kernel code. However the runtime performance overhead is virtually |
| 118 | nil until the tracepoints are actually enabled. |
Jinbum Park | 2959a5f | 2017-02-27 14:30:22 -0800 | [diff] [blame] | 119 | |
| 120 | config DEBUG_RODATA_TEST |
| 121 | bool "Testcase for the marking rodata read-only" |
| 122 | depends on STRICT_KERNEL_RWX |
| 123 | ---help--- |
| 124 | This option enables a testcase for the setting rodata read-only. |