linux-kernel - Re: [PATCH stable 6.3 v2] arch_topology: Remove early cacheinfo error message if -ENOENT

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Message-ID: <20230531085356.ru4fmtawyxo5cq5s@bogus>
Date:   Wed, 31 May 2023 09:53:56 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     Florian Fainelli <florian.fainelli@...adcom.com>
Cc:     Conor Dooley <conor@...nel.org>, stable@...r.kernel.org,
        Pierre Gondois <pierre.gondois@....com>,
        Sudeep Holla <sudeep.holla@....com>,
        Conor Dooley <conor.dooley@...rochip.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        "open list:GENERIC ARCHITECTURE TOPOLOGY" 
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH stable 6.3 v2] arch_topology: Remove early cacheinfo
 error message if -ENOENT

On Tue, May 30, 2023 at 03:42:45PM -0700, Florian Fainelli wrote:
> Hi Conor,
> 
> On 5/30/23 14:39, Conor Dooley wrote:
> > Yo Florian,
> > 
> > On Tue, May 30, 2023 at 01:19:55PM -0700, Florian Fainelli wrote:
> > > From: Pierre Gondois <pierre.gondois@....com>
> > > 
> > > commit 3522340199cc060b70f0094e3039bdb43c3f6ee1 upstream
> > > 
> > > fetch_cache_info() tries to get the number of cache leaves/levels
> > > for each CPU in order to pre-allocate memory for cacheinfo struct.
> > > Allocating this memory later triggers a:
> > >    'BUG: sleeping function called from invalid context'
> > > in PREEMPT_RT kernels.
> > > 
> > > If there is no cache related information available in DT or ACPI,
> > > fetch_cache_info() fails and an error message is printed:
> > >    'Early cacheinfo failed, ret = ...'
> > > 
> > > Not having cache information should be a valid configuration.
> > > Remove the error message if fetch_cache_info() fails with -ENOENT.
> > > 
> > > Suggested-by: Conor Dooley <conor.dooley@...rochip.com>
> > > Link: https://lore.kernel.org/all/20230404-hatred-swimmer-6fecdf33b57a@spud/
> > > Signed-off-by: Pierre Gondois <pierre.gondois@....com>
> > > Reviewed-by: Conor Dooley <conor.dooley@...rochip.com>
> > > Link: https://lore.kernel.org/r/20230414081453.244787-4-pierre.gondois@arm.com
> > > Signed-off-by: Sudeep Holla <sudeep.holla@....com>
> > > Signed-off-by: Florian Fainelli <florian.fainelli@...adcom.com>
> > 
> > How come this now needs a backport? Did the rest of the series get
> > backported, but not this one since it has no fixes tag?
> 
> Humm, indeed, this has been present in v6.3.2 since I requested it to be
> included. The error that I saw this morning was not -ENOENT, but -EINVAL.
> 
> With those patches applied, no more -EINVAL:
> 
> cacheinfo: Allow early level detection when DT/ACPI info is missing/broken
> cacheinfo: Add arm64 early level initializer implementation
> cacheinfo: Add arch specific early level initializer
> cacheinfo: Add use_arch[|_cache]_info field/function
> 
> I will submit those shortly unless we think they better not be in 6.3, in
> which case it would be nice to silence those -EINVAL errors.

I prefer this option instead of back porting all the above 4 as there are
some pending fixes for the issues found in those patches. I am fine if Greg
is happy with the backport, so no strong rejection from my side :).

-- 
Regards,
Sudeep