[PATCH] x86: fix cpu-hotplug regression
From: Andreas Herrmann
Date: Tue Nov 06 2007 - 20:20:40 EST
[PATCH] x86: fix cpu-hotplug regression
Commit d435d862baca3e25e5eec236762a43251b1e7ffc
("cpu hotplug: mce: fix cpu hotplug error handling")
changed the error handling in mce_cpu_callback.
In cases where not all CPUs are brought up during
boot (e.g. using maxcpus and additional_cpus parameters)
mce_cpu_callback now returns NOTFIY_BAD because
for such CPUs cpu_data is not completely filled when
the notifier is called. Thus mce_create_device fails right
at its beginning:
if (!mce_available(&cpu_data[cpu]))
return -EIO;
As a quick fix I suggest to check boot_cpu_data for MCE.
To reproduce this regression:
(1) boot with maxcpus=2 addtional_cpus=2 on a 4 CPU x86-64 system
(2) # echo 1 >/sys/devices/system/cpu/cpu2/online
-bash: echo: write error: Invalid argument
dmesg shows:
_cpu_up: attempt to bring up CPU 2 failed
Signed-off-by: Andreas Herrmann <andreas.herrmann3@xxxxxxx>
---
arch/x86/kernel/cpu/mcheck/mce_64.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kernel/cpu/mcheck/mce_64.c b/arch/x86/kernel/cpu/mcheck/mce_64.c
index b9f802e..5112a70 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_64.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_64.c
@@ -808,7 +808,7 @@ static __cpuinit int mce_create_device(unsigned int cpu)
int err;
int i;
- if (!mce_available(&cpu_data(cpu)))
+ if (!mce_available(&boot_cpu_data))
return -EIO;
memset(&per_cpu(device_mce, cpu).kobj, 0, sizeof(struct kobject));
--
1.5.3.4
-
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