This is a note to let you know that I've just added the patch titled
sparc64/mm: set fields in deferred pages
to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sparc64-mm-set-fields-in-deferred-pages.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Dec 14 21:30:47 CET 2017
From: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Date: Wed, 15 Nov 2017 17:36:18 -0800
Subject: sparc64/mm: set fields in deferred pages
From: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
[ Upstream commit 2a20aa171071a334d80c4e5d5af719d8374702fc ]
Without deferred struct page feature (CONFIG_DEFERRED_STRUCT_PAGE_INIT),
flags and other fields in "struct page"es are never changed prior to
first initializing struct pages by going through __init_single_page().
With deferred struct page feature enabled there is a case where we set
some fields prior to initializing:
mem_init() {
register_page_bootmem_info();
free_all_bootmem();
...
}
When register_page_bootmem_info() is called only non-deferred struct
pages are initialized. But, this function goes through some reserved
pages which might be part of the deferred, and thus are not yet
initialized.
mem_init
register_page_bootmem_info
register_page_bootmem_info_node
get_page_bootmem
.. setting fields here ..
such as: page->freelist = (void *)type;
free_all_bootmem()
free_low_memory_core_early()
for_each_reserved_mem_region()
reserve_bootmem_region()
init_reserved_page() <- Only if this is deferred reserved page
__init_single_pfn()
__init_single_page()
memset(0) <-- Loose the set fields here
We end up with similar issue as in the previous patch, where currently
we do not observe problem as memory is zeroed. But, if flag asserts are
changed we can start hitting issues.
Also, because in this patch series we will stop zeroing struct page
memory during allocation, we must make sure that struct pages are
properly initialized prior to using them.
The deferred-reserved pages are initialized in free_all_bootmem().
Therefore, the fix is to switch the above calls.
Link: http://lkml.kernel.org/r/20171013173214.27300-4-pasha.tatashin@xxxxxxxxxx
Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Reviewed-by: Steven Sistare <steven.sistare@xxxxxxxxxx>
Reviewed-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Reviewed-by: Bob Picco <bob.picco@xxxxxxxxxx>
Acked-by: David S. Miller <davem@xxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/sparc/mm/init_64.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -2215,10 +2215,17 @@ void __init mem_init(void)
{
high_memory = __va(last_valid_pfn << PAGE_SHIFT);
- register_page_bootmem_info();
free_all_bootmem();
/*
+ * Must be done after boot memory is put on freelist, because here we
+ * might set fields in deferred struct pages that have not yet been
+ * initialized, and free_all_bootmem() initializes all the reserved
+ * deferred pages for us.
+ */
+ register_page_bootmem_info();
+
+ /*
* Set up the zero page, mark it reserved, so that page count
* is not manipulated when freeing the page from user ptes.
*/
Patches currently in stable-queue which might be from pasha.tatashin@xxxxxxxxxx are
queue-3.18/sparc64-mm-set-fields-in-deferred-pages.patch