On 9/14/23 02:37, James Morse wrote:
intel_epb_init() is called as a subsys_initcall() to register cpuhp
callbacks. The callbacks make use of get_cpu_device() which will return
NULL unless register_cpu() has been called. register_cpu() is called
from topology_init(), which is also a subsys_initcall().
This is fragile. Moving the register_cpu() to a different
subsys_initcall() leads to a NULL derefernce during boot.
^^^^^^^^^^
s/derefernce/dereference
Reported by ./scripts/checkpatch.pl --codespell
Make intel_epb_init() a late_initcall(), user-space can't provide a
policy before this point anyway.
Signed-off-by: James Morse <james.morse@xxxxxxx>
---
subsys_initcall_sync() would be an option, but moving the register_cpu()
calls into ACPI also means adding a safety net for CPUs that are online
but not described properly by firmware. This lives in subsys_initcall_sync().
---
arch/x86/kernel/cpu/intel_epb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/cpu/intel_epb.c b/arch/x86/kernel/cpu/intel_epb.c
index e4c3ba91321c..f18d35fe27a9 100644
--- a/arch/x86/kernel/cpu/intel_epb.c
+++ b/arch/x86/kernel/cpu/intel_epb.c
@@ -237,4 +237,4 @@ static __init int intel_epb_init(void)
cpuhp_remove_state(CPUHP_AP_X86_INTEL_EPB_ONLINE);
return ret;
}
-subsys_initcall(intel_epb_init);
+late_initcall(intel_epb_init);
Thanks,
Gavin
