[PATCH 4.9 56/66] perf/x86/amd/power: Do not load AMD power module on !AMD platforms

From: Greg Kroah-Hartman
Date: Mon Jan 29 2018 - 15:10:00 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Xiao Liang <xiliang@xxxxxxxxxx>

commit 40d4071ce2d20840d224b4a77b5dc6f752c9ab15 upstream.

The AMD power module can be loaded on non AMD platforms, but unload fails
with the following Oops:

BUG: unable to handle kernel NULL pointer dereference at (null)
IP: __list_del_entry_valid+0x29/0x90
Call Trace:
perf_pmu_unregister+0x25/0xf0
amd_power_pmu_exit+0x1c/0xd23 [power]
SyS_delete_module+0x1a8/0x2b0
? exit_to_usermode_loop+0x8f/0xb0
entry_SYSCALL_64_fastpath+0x20/0x83

Return -ENODEV instead of 0 from the module init function if the CPU does
not match.

Fixes: c7ab62bfbe0e ("perf/x86/amd/power: Add AMD accumulated power reporting mechanism")
Signed-off-by: Xiao Liang <xiliang@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20180122061252.6394-1-xiliang@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/x86/events/amd/power.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/events/amd/power.c
+++ b/arch/x86/events/amd/power.c
@@ -277,7 +277,7 @@ static int __init amd_power_pmu_init(voi
int ret;

if (!x86_match_cpu(cpu_match))
- return 0;
+ return -ENODEV;

if (!boot_cpu_has(X86_FEATURE_ACC_POWER))
return -ENODEV;