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

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Date:   Thu, 31 Oct 2019 15:29:55 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Konstantin Khlebnikov <khlebnikov@...dex-team.ru>,
        Yazen Ghannam <Yazen.Ghannam@....com>
Cc:     Tony Luck <tony.luck@...el.com>, linux-kernel@...r.kernel.org,
        linux-edac@...r.kernel.org, x86@...nel.org
Subject: Re: [PATCH] x86/MCE/AMD: fix warning about sleep-in-atomic at early
 boot

On Thu, Oct 31, 2019 at 04:04:48PM +0300, Konstantin Khlebnikov wrote:
> 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
					     ^^^^^^^^^^

I'm assuming you hit this on latest upstream too?

>  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)) {

Yazen, any objections?

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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