"power" module can be loaded if it is not amd processor.
And user cannot unload it after loaded it. The following call trace generated
when tried to unload it.
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: __list_del_entry_valid+0x29/0x90
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 1 PID: 26046 Comm: modprobe Not tainted 4.14.13-300.fc27.x86_64 #1
Hardware name: Xen HVM domU, BIOS 4.9.1 12/12/2017
task: ffff9a138f8dddc0 task.stack: ffffb0ec41cbc000
RIP: 0010:__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
RIP: 0033:0x7fb67d78e5c7
Signed-off-by: Xiao Liang <[email protected]>
---
arch/x86/events/amd/power.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/events/amd/power.c b/arch/x86/events/amd/power.c
index a6eee5ac4f58..2aefacf5c5b2 100644
--- 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(void)
int ret;
if (!x86_match_cpu(cpu_match))
- return 0;
+ return -ENODEV;
if (!boot_cpu_has(X86_FEATURE_ACC_POWER))
return -ENODEV;
--
2.14.3
Commit-ID: 40d4071ce2d20840d224b4a77b5dc6f752c9ab15
Gitweb: https://git.kernel.org/tip/40d4071ce2d20840d224b4a77b5dc6f752c9ab15
Author: Xiao Liang <[email protected]>
AuthorDate: Mon, 22 Jan 2018 14:12:52 +0800
Committer: Thomas Gleixner <[email protected]>
CommitDate: Wed, 24 Jan 2018 13:00:35 +0100
perf/x86/amd/power: Do not load AMD power module on !AMD platforms
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 <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
---
arch/x86/events/amd/power.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/events/amd/power.c b/arch/x86/events/amd/power.c
index a6eee5a..2aefacf 100644
--- 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(void)
int ret;
if (!x86_match_cpu(cpu_match))
- return 0;
+ return -ENODEV;
if (!boot_cpu_has(X86_FEATURE_ACC_POWER))
return -ENODEV;