Linux kernel mirror (for testing)
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1config 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
10config DEBUG_PAGEALLOC
11 bool "Debug page memory allocations"
12 depends on DEBUG_KERNEL
13 depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC
14 select PAGE_EXTENSION
15 select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC
16 ---help---
17 Unmap pages from the kernel linear mapping after free_pages().
18 Depending on runtime enablement, this results in a small or large
19 slowdown, but helps to find certain types of memory corruption.
20
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
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
34config DEBUG_PAGEALLOC_ENABLE_DEFAULT
35 bool "Enable debug page memory allocations by default?"
36 depends on DEBUG_PAGEALLOC
37 ---help---
38 Enable debug page memory allocations by default? This value
39 can be overridden by debug_pagealloc=off|on.
40
41config PAGE_OWNER
42 bool "Track page owner"
43 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
44 select DEBUG_FS
45 select STACKTRACE
46 select STACKDEPOT
47 select PAGE_EXTENSION
48 help
49 This keeps track of what call chain is the owner of a page, may
50 help to find bare alloc_page(s) leaks. Even if you include this
51 feature on your build, it is disabled in default. You should pass
52 "page_owner=on" to boot parameter in order to enable it. Eats
53 a fair amount of memory if enabled. See tools/vm/page_owner_sort.c
54 for user-space helper.
55
56 If unsure, say N.
57
58config PAGE_POISONING
59 bool "Poison pages after freeing"
60 select PAGE_POISONING_NO_SANITY if HIBERNATION
61 ---help---
62 Fill the pages with poison patterns after free_pages() and verify
63 the patterns before alloc_pages. The filling of the memory helps
64 reduce the risk of information leaks from freed data. This does
65 have a potential performance impact if enabled with the
66 "page_poison=1" kernel boot option.
67
68 Note that "poison" here is not the same thing as the "HWPoison"
69 for CONFIG_MEMORY_FAILURE. This is software poisoning only.
70
71 If unsure, say N
72
73config PAGE_POISONING_NO_SANITY
74 depends on PAGE_POISONING
75 bool "Only poison, don't sanity check"
76 ---help---
77 Skip the sanity checking on alloc, only fill the pages with
78 poison on free. This reduces some of the overhead of the
79 poisoning feature.
80
81 If you are only interested in sanitization, say Y. Otherwise
82 say N.
83
84config PAGE_POISONING_ZERO
85 bool "Use zero for poisoning instead of debugging value"
86 depends on PAGE_POISONING
87 ---help---
88 Instead of using the existing poison value, fill the pages with
89 zeros. This makes it harder to detect when errors are occurring
90 due to sanitization but the zeroing at free means that it is
91 no longer necessary to write zeros when GFP_ZERO is used on
92 allocation.
93
94 If unsure, say N
95
96config DEBUG_PAGE_REF
97 bool "Enable tracepoint to track down page reference manipulation"
98 depends on DEBUG_KERNEL
99 depends on TRACEPOINTS
100 ---help---
101 This is a feature to add tracepoint for tracking down page reference
102 manipulation. This tracking is useful to diagnose functional failure
103 due to migration failures caused by page reference mismatches. Be
104 careful when enabling this feature because it adds about 30 KB to the
105 kernel code. However the runtime performance overhead is virtually
106 nil until the tracepoints are actually enabled.
107
108config DEBUG_RODATA_TEST
109 bool "Testcase for the marking rodata read-only"
110 depends on STRICT_KERNEL_RWX
111 ---help---
112 This option enables a testcase for the setting rodata read-only.