From: Borislav Petkov <firstname.lastname@example.org>
To: "“William Roche" <email@example.com>
Cc: firstname.lastname@example.org, Tony Luck <email@example.com>,
Subject: Re: [PATCH v1] RAS/CEC: Memory Corrected Errors consistent event filtering
Date: Fri, 26 Mar 2021 20:02:42 +0100 [thread overview]
Message-ID: <20210326190242.GI25229@zn.tnic> (raw)
On Fri, Mar 26, 2021 at 02:30:29PM -0400, “William Roche wrote:
> From: William Roche <firstname.lastname@example.org>
> The Corrected Error events collected by the cec_add_elem() have to be
> consistently filtered out.
> We fix the case where the value of find_elem() to find the slot of a pfn
> was mistakenly used as the return value of the function.
> Now the MCE notifiers chain relying on MCE_HANDLED_CEC would only report
> filtered corrected errors that reached the action threshold.
> Signed-off-by: William Roche <email@example.com>
> Some machines are reporting Corrected Errors events without any
> information about a PFN Soft-offlining or Invalid pfn (report given by
> the EDAC module or the mcelog daemon).
> A research showed that it reflected the first occurrence of a CE error
> on the system which should have been filtered by the RAS_CEC component.
> We could also notice that if 2 PFNs are impacted by CE errors, the PFN
> on the non-zero slot gets its CE errors reported every-time instead of
> being filtered out.
> This problem has appeared with the introduction of commit
> de0e0624d86ff9fc512dedb297f8978698abf21a where the filtering logic has
> been modified.
> Could you please review this small suggested fix ?
> Thanks in advance for any feedback you could have.
> drivers/ras/cec.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
AFAIU, I think you want something like the below untested hunk:
You set it to 0 when it cannot find an element and that "ret = 1" we can
remove because callers don't care about the offlining threshold - the
only caller that looks at its retval wants to know whether it added the
VA successfully to note that it handled the error.
diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c
index ddecf25b5dd4..a29994d726d8 100644
@@ -341,6 +341,8 @@ static int cec_add_elem(u64 pfn)
ca->array[to] = pfn << PAGE_SHIFT;
+ ret = 0;
/* Add/refresh element generation and increment count */
@@ -363,12 +365,6 @@ static int cec_add_elem(u64 pfn)
- * Return a >0 value to callers, to denote that we've reached
- * the offlining threshold.
- ret = 1;
next prev parent reply other threads:[~2021-03-26 19:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-26 18:30 [PATCH v1] RAS/CEC: Memory Corrected Errors consistent event filtering “William Roche
2021-03-26 19:02 ` Borislav Petkov [this message]
2021-03-26 22:24 ` William Roche
2021-03-26 22:43 ` Borislav Petkov
2021-03-29 9:44 ` William Roche
2021-04-01 16:12 ` Borislav Petkov
2021-04-02 16:00 ` William Roche
2021-04-02 17:07 ` Borislav Petkov
2021-04-06 15:28 ` [PATCH v2] " “William Roche
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