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| author | Qian Cai <cai@lca.pw> | 2019-02-13 02:36:03 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-02-13 03:33:18 +0300 |
| commit | 2f1ee0913ce58efe7f18fbd518bd54c598559b89 (patch) | |
| tree | c1959338eb8f79370256f1c20cda38cf9021baf5 | |
| parent | 414fd080d125408cb15d04ff4907e1dd8145c8c7 (diff) | |
| download | linux-2f1ee0913ce58efe7f18fbd518bd54c598559b89.tar.xz | |
Revert "mm: use early_pfn_to_nid in page_ext_init"
This reverts commit fe53ca54270a ("mm: use early_pfn_to_nid in
page_ext_init").
When booting a system with "page_owner=on",
start_kernel
page_ext_init
invoke_init_callbacks
init_section_page_ext
init_page_owner
init_early_allocated_pages
init_zones_in_node
init_pages_in_zone
lookup_page_ext
page_to_nid
The issue here is that page_to_nid() will not work since some page flags
have no node information until later in page_alloc_init_late() due to
DEFERRED_STRUCT_PAGE_INIT. Hence, it could trigger an out-of-bounds
access with an invalid nid.
UBSAN: Undefined behaviour in ./include/linux/mm.h:1104:50
index 7 is out of range for type 'zone [5]'
Also, kernel will panic since flags were poisoned earlier with,
CONFIG_DEBUG_VM_PGFLAGS=y
CONFIG_NODE_NOT_IN_PAGE_FLAGS=n
start_kernel
setup_arch
pagetable_init
paging_init
sparse_init
sparse_init_nid
memblock_alloc_try_nid_raw
It did not handle it well in init_pages_in_zone() which ends up calling
page_to_nid().
page:ffffea0004200000 is uninitialized and poisoned
raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff
raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff
page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p))
page_owner info is not active (free page?)
kernel BUG at include/linux/mm.h:990!
RIP: 0010:init_page_owner+0x486/0x520
This means that assumptions behind commit fe53ca54270a ("mm: use
early_pfn_to_nid in page_ext_init") are incomplete. Therefore, revert
the commit for now. A proper way to move the page_owner initialization
to sooner is to hook into memmap initialization.
Link: http://lkml.kernel.org/r/20190115202812.75820-1-cai@lca.pw
Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Michal Hocko <mhocko@kernel.org>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Yang Shi <yang.shi@linaro.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | init/main.c | 3 | ||||
| -rw-r--r-- | mm/page_ext.c | 4 |
2 files changed, 3 insertions, 4 deletions
diff --git a/init/main.c b/init/main.c index e2e80ca3165a..c86a1c8f19f4 100644 --- a/init/main.c +++ b/init/main.c @@ -695,7 +695,6 @@ asmlinkage __visible void __init start_kernel(void) initrd_start = 0; } #endif - page_ext_init(); kmemleak_init(); setup_per_cpu_pageset(); numa_policy_init(); @@ -1131,6 +1130,8 @@ static noinline void __init kernel_init_freeable(void) sched_init_smp(); page_alloc_init_late(); + /* Initialize page ext after all struct pages are initialized. */ + page_ext_init(); do_basic_setup(); diff --git a/mm/page_ext.c b/mm/page_ext.c index ae44f7adbe07..8c78b8d45117 100644 --- a/mm/page_ext.c +++ b/mm/page_ext.c @@ -398,10 +398,8 @@ void __init page_ext_init(void) * We know some arch can have a nodes layout such as * -------------pfn--------------> * N0 | N1 | N2 | N0 | N1 | N2|.... - * - * Take into account DEFERRED_STRUCT_PAGE_INIT. */ - if (early_pfn_to_nid(pfn) != nid) + if (pfn_to_nid(pfn) != nid) continue; if (init_section_page_ext(pfn, nid)) goto oom; |