The patch titled
Subject: mm: call page_ext_init() after all struct pages are initialized
has been added to the -mm tree. Its filename is
mm-move-page_ext_init-after-all-struct-pages-are-initialized-v2.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-move-page_ext_init-after-all-struct-pages-are-initialized-v2.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-move-page_ext_init-after-all-struct-pages-are-initialized-v2.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Yang Shi <yang.shi@xxxxxxxxxx>
Subject: mm: call page_ext_init() after all struct pages are initialized
When DEFERRED_STRUCT_PAGE_INIT is enabled, just a subset of memmap at boot
are initialized, then the rest are initialized in parallel by starting
one-off "pgdatinitX" kernel thread for each node X.
If page_ext_init is called before it, some pages will not have valid
extension, this may lead the below kernel oops when booting up kernel:
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff8118d982>] free_pcppages_bulk+0x2d2/0x8d0
PGD 0
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Modules linked in:
CPU: 11 PID: 106 Comm: pgdatinit1 Not tainted 4.6.0-rc5-next-20160427 #26
Hardware name: Intel Corporation S5520HC/S5520HC, BIOS S5500.86B.01.10.0025.030220091519 03/02/2009
task: ffff88017c080040 ti: ffff88017c084000 task.ti: ffff88017c084000
RIP: 0010:[<ffffffff8118d982>] [<ffffffff8118d982>] free_pcppages_bulk+0x2d2/0x8d0
RSP: 0000:ffff88017c087c48 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000980 RSI: 0000000000000080 RDI: 0000000000660401
RBP: ffff88017c087cd0 R08: 0000000000000401 R09: 0000000000000009
R10: ffff88017c080040 R11: 000000000000000a R12: 0000000000000400
R13: ffffea0019810000 R14: ffffea0019810040 R15: ffff88066cfe6080
FS: 0000000000000000(0000) GS:ffff88066cd40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000002406000 CR4: 00000000000006e0
Stack:
ffff88066cd5bbd8 ffff88066cfe6640 0000000000000000 0000000000000000
0000001f0000001f ffff88066cd5bbe8 ffffea0019810000 000000008118f53e
0000000000000009 0000000000000401 ffffffff0000000a 0000000000000001
Call Trace:
[<ffffffff8118f602>] free_hot_cold_page+0x192/0x1d0
[<ffffffff8118f69c>] __free_pages+0x5c/0x90
[<ffffffff8262a676>] __free_pages_boot_core+0x11a/0x14e
[<ffffffff8262a6fa>] deferred_free_range+0x50/0x62
[<ffffffff8262aa46>] deferred_init_memmap+0x220/0x3c3
[<ffffffff8262a826>] ? setup_per_cpu_pageset+0x35/0x35
[<ffffffff8108b1f8>] kthread+0xf8/0x110
[<ffffffff81c1b732>] ret_from_fork+0x22/0x40
[<ffffffff8108b100>] ? kthread_create_on_node+0x200/0x200
Code: 49 89 d4 48 c1 e0 06 49 01 c5 e9 de fe ff ff 4c 89 f7 44 89 4d b8 4c 89 45 c0 44 89 5d c8 48 89 4d d0 e8 62 c7 07 00 48 8b 4d d0 <48> 8b 00 44 8b 5d c8 4c 8b 45 c0 44 8b 4d b8 a8 02 0f 84 05 ff
RIP [<ffffffff8118d982>] free_pcppages_bulk+0x2d2/0x8d0
RSP <ffff88017c087c48>
CR2: 0000000000000000
Move page_ext_init() after page_alloc_init_late() to make sure page extension
is setup for all pages.
Link: http://lkml.kernel.org/r/1463696006-31360-1-git-send-email-yang.shi@xxxxxxxxxx
Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
init/main.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff -puN init/main.c~mm-move-page_ext_init-after-all-struct-pages-are-initialized-v2 init/main.c
--- a/init/main.c~mm-move-page_ext_init-after-all-struct-pages-are-initialized-v2
+++ a/init/main.c
@@ -606,7 +606,6 @@ asmlinkage __visible void __init start_k
initrd_start = 0;
}
#endif
- page_ext_init();
debug_objects_mem_init();
kmemleak_init();
setup_per_cpu_pageset();
@@ -1004,6 +1003,8 @@ static noinline void __init kernel_init_
sched_init_smp();
page_alloc_init_late();
+ /* Initialize page ext after all struct pages are initializaed */
+ page_ext_init();
do_basic_setup();
_
Patches currently in -mm which might be from yang.shi@xxxxxxxxxx are
mm-thp-simplify-the-implementation-of-mk_huge_pmd.patch
mm-page_is_guard-return-false-when-page_ext-arrays-are-not-allocated-yet.patch
mm-move-page_ext_init-after-all-struct-pages-are-initialized-v2.patch
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