linux-kernel - RE: [PATCH] x86/MCE: Statically allocate mce_banks

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Date:   Thu, 23 May 2019 19:23:08 +0000
From:   "Ghannam, Yazen" <Yazen.Ghannam@....com>
To:     Borislav Petkov <bp@...en8.de>
CC:     "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "tony.luck@...el.com" <tony.luck@...el.com>,
        "x86@...nel.org" <x86@...nel.org>
Subject: RE: [PATCH] x86/MCE: Statically allocate mce_banks_array

> -----Original Message-----
> From: Borislav Petkov <bp@...en8.de>
> Sent: Thursday, May 23, 2019 3:28 PM
> To: Ghannam, Yazen <Yazen.Ghannam@....com>
> Cc: linux-edac@...r.kernel.org; linux-kernel@...r.kernel.org; tony.luck@...el.com; x86@...nel.org
> Subject: Re: [PATCH] x86/MCE: Statically allocate mce_banks_array
> 
> 
> On Thu, May 23, 2019 at 03:03:55PM +0000, Ghannam, Yazen wrote:
> > From: Yazen Ghannam <yazen.ghannam@....com>
> >
> > The MCE control data is stored in an array of struct mce_banks. This
> > array has historically been shared by all CPUs and it was allocated
> > dynamically during the first CPU's init sequence.
> >
> > However, starting with
> >
> >       5b0883f5c7be ("x86/MCE: Make mce_banks a per-CPU array")
> >
> > the array was changed to become a per-CPU array. Each CPU would
> > dynamically allocate the array during its own init sequence.
> >
> > This seems benign expect when "Lock Debugging" config options are
> > enabled in which case the following message appears.
> >
> >       BUG: sleeping function called from invalid context at mm/slab.h:418
> >
> > The message appears during the secondary CPUs' init sequences. This seems
> > to be because these CPUs are in system_state=SYSTEM_SCHEDULING compared
> > to the primary CPU which is in system_state=SYSTEM_BOOTING.
> >
> > Allocate the mce_banks_array statically so that this issue can be
> > avoided.
> >
> > Also, remove the now unnecessary return values from
> > __mcheck_cpu_mce_banks_init() and __mcheck_cpu_cap_init().
> >
> > Fixes: 5b0883f5c7be ("x86/MCE: Make mce_banks a per-CPU array")
> > Reported-by: kernel test robot <rong.a.chen@...el.com>
> > Suggested-by: Borislav Petkov <bp@...e.de>
> > Signed-off-by: Yazen Ghannam <yazen.ghannam@....com>
> > ---
> >  arch/x86/kernel/cpu/mce/core.c | 39 ++++++++++++----------------------
> >  1 file changed, 14 insertions(+), 25 deletions(-)
> 
> Can you rediff this patch against tip/master please?
> 
> It fixes a patch which is already in -rc1 so it needs to go first, into
> urgent, before your patchset.
> 

Sure, but which patch are you referring to?

This seems to fix a patch in the set in bp/rc0+3-ras.

Thanks,
Yazen