From: Alexey Dobriyan <adobriyan@gmail.com>
To: tglx@linutronix.de
Cc: adobriyan@gmail.com, mingo@redhat.com, bp@alien8.de,
dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
linux-kernel@vger.kernel.org, peterz@infradead.org,
Jonathan.Cameron@huawei.com, linuxarm@huawei.com,
linux@roeck-us.net,
Jonathan Cameron <Jonathan.Cameron@Huawei.com>
Subject: [PATCH 1/2] x86/cpu/topology: don't write to immutable cpu_present_mask
Date: Sun, 7 Apr 2024 18:26:43 +0300 [thread overview]
Message-ID: <20240407152643.3245-1-adobriyan@gmail.com> (raw)
Workaround the following oops:
topology_hotplug_apic
topo_set_cpuids
set_cpu_possible(cpu, true);
// write to __ro_after_init section after init
adobriyan: I'm not sure what's going on, can it set unset bit here?
If not, then why does it repeat the job and set already set bits.
Anyhow, let's not oops peoples' machines for now.
Reported-by: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
Suggested-by: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
arch/x86/kernel/cpu/topology.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c
index aaca8d235dc2..42f4a17f8019 100644
--- a/arch/x86/kernel/cpu/topology.c
+++ b/arch/x86/kernel/cpu/topology.c
@@ -117,13 +117,18 @@ static __init int topo_get_cpunr(u32 apic_id)
return topo_info.nr_assigned_cpus++;
}
-static void topo_set_cpuids(unsigned int cpu, u32 apic_id, u32 acpi_id)
+static void topo_set_cpuids(unsigned int cpu, u32 apic_id, u32 acpi_id, bool from_init)
{
#if defined(CONFIG_SMP) || defined(CONFIG_X86_64)
early_per_cpu(x86_cpu_to_apicid, cpu) = apic_id;
early_per_cpu(x86_cpu_to_acpiid, cpu) = acpi_id;
#endif
- set_cpu_possible(cpu, true);
+ if (from_init) {
+ set_cpu_possible(cpu, true);
+ } else {
+ /* cpu_possible_mask is supposed to be fixed by now. */
+ WARN_ON(!cpumask_test_cpu(cpu, cpu_possible_mask));
+ }
set_cpu_present(cpu, true);
}
@@ -191,7 +196,7 @@ static __init void topo_register_apic(u32 apic_id, u32 acpi_id, bool present)
cpu = topo_get_cpunr(apic_id);
cpuid_to_apicid[cpu] = apic_id;
- topo_set_cpuids(cpu, apic_id, acpi_id);
+ topo_set_cpuids(cpu, apic_id, acpi_id, true);
} else {
u32 pkgid = topo_apicid(apic_id, TOPO_PKG_DOMAIN);
@@ -343,7 +348,7 @@ int topology_hotplug_apic(u32 apic_id, u32 acpi_id)
return -ENOSPC;
set_bit(apic_id, phys_cpu_present_map);
- topo_set_cpuids(cpu, apic_id, acpi_id);
+ topo_set_cpuids(cpu, apic_id, acpi_id, false);
cpu_mark_primary_thread(cpu, apic_id);
return cpu;
}
--
2.43.2
next reply other threads:[~2024-04-07 15:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-07 15:26 Alexey Dobriyan [this message]
2024-04-08 13:31 ` [PATCH 1/2] x86/cpu/topology: don't write to immutable cpu_present_mask Thomas Gleixner
2024-04-09 8:42 ` Ingo Molnar
2024-04-09 9:24 ` Peter Zijlstra
2024-04-10 13:33 ` [tip: x86/alternatives] x86/topology: Don't update cpu_possible_map in topo_set_cpuids() tip-bot2 for Thomas Gleixner
2024-04-10 13:41 ` [tip: x86/urgent] " tip-bot2 for Thomas Gleixner
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