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

From: Konstantin Khlebnikov
Date: Thu Oct 31 2019 - 09:04:54 EST


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@xxxxxxxxxxxxxx>
---
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;
}