Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk()

From	"Kani, Toshimitsu" <toshi.kani@hpe.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk()
Date	2017-08-14 21:10 +0200
Message-ID	<uesUp-83a-7@gated-at.bofh.it> (permalink)
References	(6 earlier) <uer2h-6Tj-7@gated-at.bofh.it> <uerOF-79Q-7@gated-at.bofh.it> <uerYl-7s4-1@gated-at.bofh.it> <ues81-7vo-3@gated-at.bofh.it> <uesrn-7E5-3@gated-at.bofh.it>
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On Mon, 2017-08-14 at 20:35 +0200, Borislav Petkov wrote:
> On Mon, Aug 14, 2017 at 06:17:47PM +0000, Kani, Toshimitsu wrote:
> > Right, ghes_edac_report_mem_error() gets serialized per a GHES
> > entry, but not globally.
> 
> Globally what?

GHES v2's ACK is not a global lock.  So, it does not guarantee that
ghes_edac_report_mem_error() never gets called concurrently.

> What is the actual potential scenario for concurrency issues you see?
> Example pls.

ghes_probe() supports multiple sources defined in
acpi_hest_notify_types.  Say, there are two entries for memory errors,
one with ACPI_HEST_NOTIFY_EXTERNAL and the other with
ACPI_HEST_NOTIFY_SCI.  They may report errors independently.  While
ghes_edac_report_mem_error() is being called from the SCI, it can be
called from the ext interrupt at a same time.

I do not know how likely we see such case, but the code should be
written according to the spec.

Thanks,
-Toshi

Thread

Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() "Kani, Toshimitsu" <toshi.kani@hpe.com> - 2017-08-14 18:00 +0200
  Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Borislav Petkov <bp@alien8.de> - 2017-08-14 18:30 +0200
    Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() "Kani, Toshimitsu" <toshi.kani@hpe.com> - 2017-08-14 18:50 +0200
      Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Borislav Petkov <bp@alien8.de> - 2017-08-14 19:10 +0200
        Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() "Kani, Toshimitsu" <toshi.kani@hpe.com> - 2017-08-14 20:00 +0200
          Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Borislav Petkov <bp@alien8.de> - 2017-08-14 20:10 +0200
            Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() "Kani, Toshimitsu" <toshi.kani@hpe.com> - 2017-08-14 20:20 +0200
              Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Borislav Petkov <bp@alien8.de> - 2017-08-14 20:40 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() "Kani, Toshimitsu" <toshi.kani@hpe.com> - 2017-08-14 21:10 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Borislav Petkov <bp@alien8.de> - 2017-08-14 21:40 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() "Kani, Toshimitsu" <toshi.kani@hpe.com> - 2017-08-14 22:20 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Borislav Petkov <bp@alien8.de> - 2017-08-14 22:40 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() "Kani, Toshimitsu" <toshi.kani@hpe.com> - 2017-08-15 17:40 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() "Luck, Tony" <tony.luck@intel.com> - 2017-08-15 17:50 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() "Kani, Toshimitsu" <toshi.kani@hpe.com> - 2017-08-15 18:00 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Borislav Petkov <bp@alien8.de> - 2017-08-16 10:30 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Borislav Petkov <bp@alien8.de> - 2017-08-16 13:30 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Steven Rostedt <rostedt@goodmis.org> - 2017-08-16 16:00 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Borislav Petkov <bp@alien8.de> - 2017-08-16 16:10 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Steven Rostedt <rostedt@goodmis.org> - 2017-08-16 16:30 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Borislav Petkov <bp@alien8.de> - 2017-08-16 19:40 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() "Kani, Toshimitsu" <toshi.kani@hpe.com> - 2017-08-16 17:30 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Borislav Petkov <bp@alien8.de> - 2017-08-16 18:50 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() "Kani, Toshimitsu" <toshi.kani@hpe.com> - 2017-08-16 19:30 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Borislav Petkov <bp@alien8.de> - 2017-08-16 19:50 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() "Kani, Toshimitsu" <toshi.kani@hpe.com> - 2017-08-16 20:10 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() "Kani, Toshimitsu" <toshi.kani@hpe.com> - 2017-08-17 23:10 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Borislav Petkov <bp@alien8.de> - 2017-08-21 11:30 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() Borislav Petkov <bp@alien8.de> - 2017-08-15 18:00 +0200
                Re: [PATCH v2 4/7] ghes_edac: avoid multiple calls to dmi_walk() "Kani, Toshimitsu" <toshi.kani@hpe.com> - 2017-08-15 18:30 +0200

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