blob: b9019d42618bbe7daffbc503bab606a382ee0106 [file] [log] [blame]
Joonsoo Kimeefa8642014-12-12 16:55:46 -08001config 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 Mitaee3b4292009-04-02 16:56:30 -070010config DEBUG_PAGEALLOC
11 bool "Debug page memory allocations"
Akinobu Mita7bc32f62011-03-22 16:32:46 -070012 depends on DEBUG_KERNEL
13 depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC
Vegard Nossum7d46d9e2008-04-04 00:51:41 +020014 depends on !KMEMCHECK
Joonsoo Kime30825f2014-12-12 16:55:49 -080015 select PAGE_EXTENSION
Akinobu Mita7bc32f62011-03-22 16:32:46 -070016 select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC
Akinobu Mitaee3b4292009-04-02 16:56:30 -070017 ---help---
18 Unmap pages from the kernel linear mapping after free_pages().
Christian Borntraegerea6eabb2016-03-15 14:55:30 -070019 Depending on runtime enablement, this results in a small or large
20 slowdown, but helps to find certain types of memory corruption.
Akinobu Mitaee3b4292009-04-02 16:56:30 -070021
Akinobu Mita7bc32f62011-03-22 16:32:46 -070022 For architectures which don't enable ARCH_SUPPORTS_DEBUG_PAGEALLOC,
23 fill the pages with poison patterns after free_pages() and verify
24 the patterns before alloc_pages(). Additionally,
25 this option cannot be enabled in combination with hibernation as
26 that would result in incorrect warnings of memory corruption after
27 a resume because free pages are not saved to the suspend image.
28
Christian Borntraegerea6eabb2016-03-15 14:55:30 -070029 By default this option will have a small overhead, e.g. by not
30 allowing the kernel mapping to be backed by large pages on some
31 architectures. Even bigger overhead comes when the debugging is
32 enabled by DEBUG_PAGEALLOC_ENABLE_DEFAULT or the debug_pagealloc
33 command line parameter.
34
Channagoud Kadabi281d6862017-03-15 14:26:08 -070035config SLUB_DEBUG_PANIC_ON
36 bool "Enable to Panic on SLUB corruption detection"
37 depends on SLUB_DEBUG
38 help
39 SLUB has a resiliency feature enabled which restores bytes in
40 order for production environments to continue to operate. IN
41 debug options this may not be desirable as it prevents from
42 investigating the root cause which may be rooted within cache
43 or memory.
44
Christian Borntraegerea6eabb2016-03-15 14:55:30 -070045config DEBUG_PAGEALLOC_ENABLE_DEFAULT
46 bool "Enable debug page memory allocations by default?"
47 default n
48 depends on DEBUG_PAGEALLOC
49 ---help---
50 Enable debug page memory allocations by default? This value
51 can be overridden by debug_pagealloc=off|on.
52
Akinobu Mita6a11f752009-03-31 15:23:17 -070053config PAGE_POISONING
Laura Abbott8823b1d2016-03-15 14:56:27 -070054 bool "Poison pages after freeing"
55 select PAGE_EXTENSION
56 select PAGE_POISONING_NO_SANITY if HIBERNATION
57 ---help---
58 Fill the pages with poison patterns after free_pages() and verify
59 the patterns before alloc_pages. The filling of the memory helps
60 reduce the risk of information leaks from freed data. This does
61 have a potential performance impact.
62
63 Note that "poison" here is not the same thing as the "HWPoison"
64 for CONFIG_MEMORY_FAILURE. This is software poisoning only.
65
66 If unsure, say N
67
68config PAGE_POISONING_NO_SANITY
69 depends on PAGE_POISONING
70 bool "Only poison, don't sanity check"
71 ---help---
72 Skip the sanity checking on alloc, only fill the pages with
73 poison on free. This reduces some of the overhead of the
74 poisoning feature.
75
76 If you are only interested in sanitization, say Y. Otherwise
77 say N.
Laura Abbott1414c7f2016-03-15 14:56:30 -070078
79config PAGE_POISONING_ZERO
80 bool "Use zero for poisoning instead of random data"
81 depends on PAGE_POISONING
82 ---help---
83 Instead of using the existing poison value, fill the pages with
84 zeros. This makes it harder to detect when errors are occurring
85 due to sanitization but the zeroing at free means that it is
86 no longer necessary to write zeros when GFP_ZERO is used on
87 allocation.
88
Laura Abbott1414c7f2016-03-15 14:56:30 -070089 If unsure, say N
Joonsoo Kim95813b82016-03-17 14:19:29 -070090 bool
91
92config DEBUG_PAGE_REF
93 bool "Enable tracepoint to track down page reference manipulation"
94 depends on DEBUG_KERNEL
95 depends on TRACEPOINTS
96 ---help---
97 This is a feature to add tracepoint for tracking down page reference
98 manipulation. This tracking is useful to diagnose functional failure
99 due to migration failures caused by page reference mismatches. Be
100 careful when enabling this feature because it adds about 30 KB to the
101 kernel code. However the runtime performance overhead is virtually
102 nil until the tracepoints are actually enabled.