linux-kernel - [PATCH] x86/MCE/AMD: fix warning about sleep-in-atomic at early boot

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Message-ID: <157252708836.3876.4604398213417262402.stgit@buzz>
Date:   Thu, 31 Oct 2019 16:04:48 +0300
From:   Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
To:     Tony Luck <tony.luck@...el.com>, Borislav Petkov <bp@...en8.de>,
        linux-kernel@...r.kernel.org, linux-edac@...r.kernel.org
Cc:     x86@...nel.org
Subject: [PATCH] x86/MCE/AMD: fix warning about sleep-in-atomic at early boot

Function smca_configure() is called only for current cpu thus
rdmsr_safe_on_cpu() could be replaced with atomic rdmsr_safe().

 BUG: sleeping function called from invalid context at kernel/sched/completion.c:99
 in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: swapper/1
 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.19.79-16 #1
 Hardware name: GIGABYTE R181-Z90-00/MZ91-FS0-00, BIOS R11 10/25/2019
 Call Trace:
  dump_stack+0x5c/0x7b
  ___might_sleep+0xec/0x110
  wait_for_completion+0x39/0x160
  ? __rdmsr_safe_on_cpu+0x45/0x60
  rdmsr_safe_on_cpu+0xae/0xf0
  ? wrmsr_on_cpus+0x20/0x20
  ? machine_check_poll+0xfd/0x1f0
  ? mce_amd_feature_init+0x190/0x2d0
  mce_amd_feature_init+0x190/0x2d0
  mcheck_cpu_init+0x11a/0x460
  identify_cpu+0x3e2/0x560
  identify_secondary_cpu+0x13/0x80
  smp_store_cpu_info+0x45/0x50
  start_secondary+0xaa/0x200
  secondary_startup_64+0xa4/0xb0

Except warning in kernel log everything works fine.

Fixes: 5896820e0aa3 ("x86/mce/AMD, EDAC/mce_amd: Define and use tables for known SMCA IP types")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
---
 arch/x86/kernel/cpu/mce/amd.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c
index 6ea7fdc82f3c..c7ab0d38af79 100644
--- a/arch/x86/kernel/cpu/mce/amd.c
+++ b/arch/x86/kernel/cpu/mce/amd.c
@@ -269,7 +269,7 @@ static void smca_configure(unsigned int bank, unsigned int cpu)
 	if (smca_banks[bank].hwid)
 		return;

-	if (rdmsr_safe_on_cpu(cpu, MSR_AMD64_SMCA_MCx_IPID(bank), &low, &high)) {
+	if (rdmsr_safe(MSR_AMD64_SMCA_MCx_IPID(bank), &low, &high)) {
 		pr_warn("Failed to read MCA_IPID for bank %d\n", bank);
 		return;
 	}