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Commit | Line | Data |
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ecf3b270 SL |
1 | From bc0c88889784544219b105d48b313218514965d9 Mon Sep 17 00:00:00 2001 |
2 | From: Qian Cai <cai@lca.pw> | |
3 | Date: Tue, 12 Feb 2019 15:36:03 -0800 | |
4 | Subject: Revert "mm: use early_pfn_to_nid in page_ext_init" | |
5 | ||
6 | [ Upstream commit 2f1ee0913ce58efe7f18fbd518bd54c598559b89 ] | |
7 | ||
8 | This reverts commit fe53ca54270a ("mm: use early_pfn_to_nid in | |
9 | page_ext_init"). | |
10 | ||
11 | When booting a system with "page_owner=on", | |
12 | ||
13 | start_kernel | |
14 | page_ext_init | |
15 | invoke_init_callbacks | |
16 | init_section_page_ext | |
17 | init_page_owner | |
18 | init_early_allocated_pages | |
19 | init_zones_in_node | |
20 | init_pages_in_zone | |
21 | lookup_page_ext | |
22 | page_to_nid | |
23 | ||
24 | The issue here is that page_to_nid() will not work since some page flags | |
25 | have no node information until later in page_alloc_init_late() due to | |
26 | DEFERRED_STRUCT_PAGE_INIT. Hence, it could trigger an out-of-bounds | |
27 | access with an invalid nid. | |
28 | ||
29 | UBSAN: Undefined behaviour in ./include/linux/mm.h:1104:50 | |
30 | index 7 is out of range for type 'zone [5]' | |
31 | ||
32 | Also, kernel will panic since flags were poisoned earlier with, | |
33 | ||
34 | CONFIG_DEBUG_VM_PGFLAGS=y | |
35 | CONFIG_NODE_NOT_IN_PAGE_FLAGS=n | |
36 | ||
37 | start_kernel | |
38 | setup_arch | |
39 | pagetable_init | |
40 | paging_init | |
41 | sparse_init | |
42 | sparse_init_nid | |
43 | memblock_alloc_try_nid_raw | |
44 | ||
45 | It did not handle it well in init_pages_in_zone() which ends up calling | |
46 | page_to_nid(). | |
47 | ||
48 | page:ffffea0004200000 is uninitialized and poisoned | |
49 | raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff | |
50 | raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff | |
51 | page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) | |
52 | page_owner info is not active (free page?) | |
53 | kernel BUG at include/linux/mm.h:990! | |
54 | RIP: 0010:init_page_owner+0x486/0x520 | |
55 | ||
56 | This means that assumptions behind commit fe53ca54270a ("mm: use | |
57 | early_pfn_to_nid in page_ext_init") are incomplete. Therefore, revert | |
58 | the commit for now. A proper way to move the page_owner initialization | |
59 | to sooner is to hook into memmap initialization. | |
60 | ||
61 | Link: http://lkml.kernel.org/r/20190115202812.75820-1-cai@lca.pw | |
62 | Signed-off-by: Qian Cai <cai@lca.pw> | |
63 | Acked-by: Michal Hocko <mhocko@kernel.org> | |
64 | Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com> | |
65 | Cc: Mel Gorman <mgorman@techsingularity.net> | |
66 | Cc: Yang Shi <yang.shi@linaro.org> | |
67 | Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> | |
68 | Signed-off-by: Andrew Morton <akpm@linux-foundation.org> | |
69 | Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> | |
70 | Signed-off-by: Sasha Levin <sashal@kernel.org> | |
71 | --- | |
72 | init/main.c | 3 ++- | |
73 | mm/page_ext.c | 4 +--- | |
74 | 2 files changed, 3 insertions(+), 4 deletions(-) | |
75 | ||
76 | diff --git a/init/main.c b/init/main.c | |
77 | index c4a45145e102..3d3d79c5a232 100644 | |
78 | --- a/init/main.c | |
79 | +++ b/init/main.c | |
80 | @@ -663,7 +663,6 @@ asmlinkage __visible void __init start_kernel(void) | |
81 | initrd_start = 0; | |
82 | } | |
83 | #endif | |
84 | - page_ext_init(); | |
85 | kmemleak_init(); | |
86 | debug_objects_mem_init(); | |
87 | setup_per_cpu_pageset(); | |
88 | @@ -1069,6 +1068,8 @@ static noinline void __init kernel_init_freeable(void) | |
89 | sched_init_smp(); | |
90 | ||
91 | page_alloc_init_late(); | |
92 | + /* Initialize page ext after all struct pages are initialized. */ | |
93 | + page_ext_init(); | |
94 | ||
95 | do_basic_setup(); | |
96 | ||
97 | diff --git a/mm/page_ext.c b/mm/page_ext.c | |
98 | index 2c16216c29b6..2c44f5b78435 100644 | |
99 | --- a/mm/page_ext.c | |
100 | +++ b/mm/page_ext.c | |
101 | @@ -396,10 +396,8 @@ void __init page_ext_init(void) | |
102 | * We know some arch can have a nodes layout such as | |
103 | * -------------pfn--------------> | |
104 | * N0 | N1 | N2 | N0 | N1 | N2|.... | |
105 | - * | |
106 | - * Take into account DEFERRED_STRUCT_PAGE_INIT. | |
107 | */ | |
108 | - if (early_pfn_to_nid(pfn) != nid) | |
109 | + if (pfn_to_nid(pfn) != nid) | |
110 | continue; | |
111 | if (init_section_page_ext(pfn, nid)) | |
112 | goto oom; | |
113 | -- | |
114 | 2.19.1 | |
115 |