[PATCH 1/3] x86/topology: Fix logical pkg mapping

From: Peter Zijlstra
Date: Fri Mar 18 2016 - 11:08:23 EST


That first branch testing pkg against __max_logical_packages is wrong,
because if the first pkg id is larger, then the find_first_zero will
find us logical package id 0. However, if the second pkg id is indeed
0, we'll again claim it without testing if it was already taken.

Also, it fails to print the mapping.

Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Andreas Herrmann <aherrmann@xxxxxxxx>
Reported-by: Xiong Zhou <jencce.kernel@xxxxxxxxx>
Fixes: 1f12e32f4cd5 ("x86/topology: Create logical package id")
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20160317095220.GO6344@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
---
arch/x86/kernel/cpu/amd.c | 8 ++++----
arch/x86/kernel/smpboot.c | 11 ++++++-----
2 files changed, 10 insertions(+), 9 deletions(-)

--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -274,11 +274,6 @@ int topology_update_package_map(unsigned
if (test_and_set_bit(pkg, physical_package_map))
goto found;

- if (pkg < __max_logical_packages) {
- set_bit(pkg, logical_package_map);
- physical_to_logical_pkg[pkg] = pkg;
- goto found;
- }
new = find_first_zero_bit(logical_package_map, __max_logical_packages);
if (new >= __max_logical_packages) {
physical_to_logical_pkg[pkg] = -1;