[tip: x86/urgent] x86, fakenuma: Fix invalid starting node ID

[tip-bot2 for Huang Ying]

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     ccae0f36d500aef727f98acd8d0601e6b262a513
Gitweb:        https://git.kernel.org/tip/ccae0f36d500aef727f98acd8d0601e6b262a513
Author:        Huang Ying <ying.huang@xxxxxxxxx>
AuthorDate:    Fri, 04 Sep 2020 14:10:47 +08:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Fri, 04 Sep 2020 08:56:13 +02:00

x86, fakenuma: Fix invalid starting node ID

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@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200904061047.612950-1-ying.huang@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 c5174b4..683cd12 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)