linux-kernel - Re: [RFC PATCH v2 05/35] drivers: base: Print a warning instead of panic() when register

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Message-ID: <ZQLX+XEe2gD/btaQ@shell.armlinux.org.uk>
Date:   Thu, 14 Sep 2023 10:52:57 +0100
From:   "Russell King (Oracle)" <linux@...linux.org.uk>
To:     James Morse <james.morse@....com>
Cc:     linux-pm@...r.kernel.org, loongarch@...ts.linux.dev,
        linux-acpi@...r.kernel.org, linux-arch@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-riscv@...ts.infradead.org, kvmarm@...ts.linux.dev,
        x86@...nel.org, Salil Mehta <salil.mehta@...wei.com>,
        Jean-Philippe Brucker <jean-philippe@...aro.org>,
        jianyong.wu@....com, justin.he@....com
Subject: Re: [RFC PATCH v2 05/35] drivers: base: Print a warning instead of
 panic() when register_cpu() fails

On Wed, Sep 13, 2023 at 04:37:53PM +0000, James Morse wrote:
> loongarch, mips, parisc, riscv and sh all print a warning if
> register_cpu() returns an error. Architectures that use
> GENERIC_CPU_DEVICES call panic() instead.
> 
> Errors in this path indicate something is wrong with the firmware
> description of the platform, but the kernel is able to keep running.
> 
> Downgrade this to a warning to make it easier to debug this issue.
> 
> This will allow architectures that switching over to GENERIC_CPU_DEVICES
> to drop their warning, but keep the existing behaviour.
> 
> Signed-off-by: James Morse <james.morse@....com>

Assuming other architectures do similar to x86 (which only return the
error code from register_cpu()), the only error that would occur here
is if device_register() fails, which would be catastophic, and I
suspect the system would fail to boot anyway.

Downgrading the panic to a warning at least gives us a chance that
the system may come up sufficiently to examine what happened, so I
think this makes sense:

Reviewed-by: Russell King (Oracle) <rmk+kernel@...linux.org.uk>

-- 
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