| From | Russell King (Oracle) <> | Subject | [PATCH 02/21] x86: intel_epb: Don't rely on link order | Date | Tue, 21 Nov 2023 13:44:00 +0000 |
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From: James Morse <james.morse@arm.com>
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 dereference during boot.
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@arm.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> --- 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); -- 2.30.2
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