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Andreas Herrmann authored
Commit d435d862 ("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@amd.com> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de>
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