[PATCH 4.19 48/88] x86, fakenuma: Fix invalid starting node ID

Greg Kroah-Hartman
2020-09-08T18:30:36Z

From: Huang Ying <ying.huang@intel.com>

[ Upstream commit ccae0f36d500aef727f98acd8d0601e6b262a513 ]

Commit:

cc9aec03e58f ("x86/numa_emulation: Introduce uniform split capability")

uses "-1" as the starting node ID, which causes the strange kernel log as
follows, 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 the kernel crashes:

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

Fix this bug via using 0 as the starting node ID. This restores the
original behavior before cc9aec03e58f.

[ mingo: Massaged the changelog. ]

Fixes: cc9aec03e58f ("x86/numa_emulation: Introduce uniform split capability")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200904061047.612950-1-ying.huang@intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 d71d72cf6c666..4686757a74d75 100644
--- a/arch/x86/mm/numa_emulation.c
+++ b/arch/x86/mm/numa_emulation.c
@@ -322,7 +322,7 @@ 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);
}

int __init setup_emu2phys_nid(int *dfl_phys_nid)
--
2.25.1