linux-kernel - RE: [PATCH 4/4 Rebase] x86, MCE: Avoid potential deadlock in MCE context

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Message-ID: <3908561D78D1C84285E8C5FCA982C28F32A8E51A@ORSMSX114.amr.corp.intel.com>
Date:	Mon, 8 Jun 2015 20:03:08 +0000
From:	"Luck, Tony" <tony.luck@...el.com>
To:	Borislav Petkov <bp@...e.de>
CC:	"Chen, Gong" <gong.chen@...ux.intel.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 4/4 Rebase] x86, MCE: Avoid potential deadlock in MCE
 context

> So AFAINM, we want to do MCE work only after we've logged something to
> the genpool. So we can do the much simplified thing below and kick the
> workqueue from within mce_log() as everything that logs, calls that
> function.
>
> Tony, any concerns?

@@ -156,7 +156,8 @@ void mce_log(struct mce *mce)
 	/* Emit the trace record: */
 	trace_mce_record(mce);
 
-	atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
+	mce_genpool_add(mce);
+	irq_work_queue(&mce_irq_work);

Is it safe to call irq_work_queue() from MCE context?  If that is OK, then
I don't have any concerns.

-Tony