Re: [PATCH 1/3] drivers/edac: Add L1 and L2 error detection for A72
From: Vijay Balakrishna <vijayb@linux.microsoft.com>
Date: 2025-05-20 23:20:11
Also in:
linux-edac, lkml
On 5/20/2025 1:04 PM, Borislav Petkov wrote:
On Tue, May 20, 2025 at 12:54:32PM -0700, Vijay Balakrishna wrote:quoted
On 5/20/2025 9:09 AM, Vijay Balakrishna wrote:quoted
On 5/19/2025 1:51 AM, Borislav Petkov wrote:quoted
I'd venture a guess you need to protect here against CPU hotplug...quoted
+ for_each_cpu_and(cpu, cpu_online_mask, &compat_mask) { + smp_call_function_single(cpu, read_errors, &merrsr, true); + report_errors(edac_ctl, cpu, &merrsr); + } +} +Hi Boris, I appreciate you highlighting the CPU hotplug issue. Upon further review of surrounding code, I realized we must ensure that the data passed to read_errors() is per-CPU.Actually, per-CPU data not needed as we are passing true -- wait until function has completed on other CPUs.What happens if @cpu above gets offlined right before you do smp_call_function_single() ?
We can see inconsistent behavior or kernel crash/hang. You are correct, we need to protect against CPU hotplug. I will add cpus_read_lock()/cpus_read_unlock(). Thanks, Vijay