From: Borislav Petkov <bp@alien8.de>
To: rui wang <ruiv.wang@gmail.com>
Cc: "Luck, Tony" <tony.luck@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"gong.chen@linux.intel.com" <gong.chen@linux.intel.com>,
"Wang, Rui Y" <rui.y.wang@intel.com>
Subject: Re: [PATCH v3] x86/mce: Try printing all machine check banks known before panic
Date: Fri, 21 Nov 2014 17:41:40 +0100 [thread overview]
Message-ID: <20141121164140.GA4274@pd.tnic> (raw)
In-Reply-To: <CANVTcTa++Ef04JSYpfrCVuua5B0Wv=ASyr_H7nfHSQ-vC9GV3Q@mail.gmail.com>
On Fri, Nov 21, 2014 at 09:20:59AM +0800, rui wang wrote:
> We've found there are cases after mce_log() has been called, we then
> decide to panic, but print_mce() can't find anything in the mcelog
> buffer. I think the mcelog buffer can be consumed by the user space
> daemon (possibly on a different CPU). We may end up seeing the "panic
> from unknown source" message without printing any mca banks, which is
> one of the cases where this bug was originated.
Ok, so modify the mcelog buffer to not zero out its entries when they're
being read out in userspace through mce_chrdev_read() but simply to
leave them in. Then you can read them out again on panic time. The mce
log buffer will have to become a circular buffer or something like that.
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
--
next prev parent reply other threads:[~2014-11-21 16:41 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-19 9:22 [PATCH v3] x86/mce: Try printing all machine check banks known before panic ruiv.wang
2014-11-19 10:29 ` Borislav Petkov
2014-11-19 23:34 ` Luck, Tony
2014-11-20 10:15 ` Borislav Petkov
2014-11-21 1:20 ` rui wang
2014-11-21 16:41 ` Borislav Petkov [this message]
2014-11-21 17:20 ` Luck, Tony
2014-11-21 18:13 ` Borislav Petkov
2014-11-21 21:31 ` Luck, Tony
2014-11-21 21:35 ` Borislav Petkov
2014-11-21 21:59 ` Luck, Tony
2014-11-23 20:55 ` Borislav Petkov
2014-11-22 2:16 ` rui wang
2014-11-22 9:44 ` Borislav Petkov
2014-11-22 15:32 ` rui wang
2014-11-22 16:31 ` Borislav Petkov
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