This is a note to let you know that I've just added the patch titled
MIPS: loongsoon64: Reserve memory below starting pfn to prevent Oops
to the 5.10-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:
mips-loongsoon64-reserve-memory-below-starting-pfn-t.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 3dc7b5d45385d9ada595dabfc156a3d0f4b55bb5
Author: zhanglianjie <zhanglianjie@xxxxxxxxxxxxx>
Date: Mon Jun 28 17:11:05 2021 +0800
MIPS: loongsoon64: Reserve memory below starting pfn to prevent Oops
[ Upstream commit 6817c944430d00f71ccaa9c99ff5b0096aeb7873 ]
The cause of the problem is as follows:
1. when cat /sys/devices/system/memory/memory0/valid_zones,
test_pages_in_a_zone() will be called.
2. test_pages_in_a_zone() finds the zone according to stat_pfn = 0.
The smallest pfn of the numa node in the mips architecture is 128,
and the page corresponding to the previous 0~127 pfn is not
initialized (page->flags is 0xFFFFFFFF)
3. The nid and zonenum obtained using page_zone(pfn_to_page(0)) are out
of bounds in the corresponding array,
&NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)],
access to the out-of-bounds zone member variables appear abnormal,
resulting in Oops.
Therefore, it is necessary to keep the page between 0 and the minimum
pfn to prevent Oops from appearing.
Signed-off-by: zhanglianjie <zhanglianjie@xxxxxxxxxxxxx>
Signed-off-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/mips/loongson64/numa.c b/arch/mips/loongson64/numa.c
index cf9459f79f9b..e4c461df3ee6 100644
--- a/arch/mips/loongson64/numa.c
+++ b/arch/mips/loongson64/numa.c
@@ -182,6 +182,9 @@ static void __init node_mem_init(unsigned int node)
if (node_end_pfn(0) >= (0xffffffff >> PAGE_SHIFT))
memblock_reserve((node_addrspace_offset | 0xfe000000),
32 << 20);
+
+ /* Reserve pfn range 0~node[0]->node_start_pfn */
+ memblock_reserve(0, PAGE_SIZE * start_pfn);
}
}
