[PATCH RESEND] x86, fakenuma: Fix invalid starting node ID

From: Huang Ying
Date: Fri Sep 04 2020 - 02:11:07 EST


Commit cc9aec03e58f ("x86/numa_emulation: Introduce uniform split
capability") uses "-1" as the starting node ID, which causes the
strange kernel log as following, when "numa=fake=32G" is added to the
kernel command line.

Faking node -1 at [mem 0x0000000000000000-0x0000000893ffffff] (35136MB)
Faking node 0 at [mem 0x0000001840000000-0x000000203fffffff] (32768MB)
Faking node 1 at [mem 0x0000000894000000-0x000000183fffffff] (64192MB)
Faking node 2 at [mem 0x0000002040000000-0x000000283fffffff] (32768MB)
Faking node 3 at [mem 0x0000002840000000-0x000000303fffffff] (32768MB)

And finally kernel BUG as following,

BUG: Bad page state in process swapper pfn:00011
page:(____ptrval____) refcount:0 mapcount:1 mapping:(____ptrval____) index:0x55cd7e44b270 pfn:0x11
failed to read mapping contents, not a valid kernel address?
flags: 0x5(locked|uptodate)
raw: 0000000000000005 000055cd7e44af30 000055cd7e44af50 0000000100000006
raw: 000055cd7e44b270 000055cd7e44b290 0000000000000000 000055cd7e44b510
page dumped because: page still charged to cgroup
page->mem_cgroup:000055cd7e44b510
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 5.9.0-rc2 #1
Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019
Call Trace:
dump_stack+0x57/0x80
bad_page.cold+0x63/0x94
__free_pages_ok+0x33f/0x360
memblock_free_all+0x127/0x195
mem_init+0x23/0x1f5
start_kernel+0x219/0x4f5
secondary_startup_64+0xb6/0xc0

Fixes this bug via using 0 as the starting node ID. This restores the
original behavior before the commit cc9aec03e58f ("x86/numa_emulation:
Introduce uniform split capability").

Fixes: cc9aec03e58f ("x86/numa_emulation: Introduce uniform split capability")
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
---
arch/x86/mm/numa_emulation.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/mm/numa_emulation.c b/arch/x86/mm/numa_emulation.c
index c5174b4e318b..683cd12f4793 100644
--- a/arch/x86/mm/numa_emulation.c
+++ b/arch/x86/mm/numa_emulation.c
@@ -321,7 +321,7 @@ static int __init split_nodes_size_interleave(struct numa_meminfo *ei,
u64 addr, u64 max_addr, u64 size)
{
return split_nodes_size_interleave_uniform(ei, pi, addr, max_addr, size,
- 0, NULL, NUMA_NO_NODE);
+ 0, NULL, 0);
}

static int __init setup_emu2phys_nid(int *dfl_phys_nid)
--
2.28.0