linux-kernel - RE: [PATCH] pstore: avoid recursive spinlocks in the oops_in

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Date:	Thu, 20 Sep 2012 23:09:36 +0000
From:	"Luck, Tony" <tony.luck@...el.com>
To:	Anton Vorontsov <anton.vorontsov@...aro.org>,
	"Liu, Chuansheng" <chuansheng.liu@...el.com>
CC:	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
	"keescook@...omium.org" <keescook@...omium.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Colin Cross <ccross@...roid.com>
Subject: RE: [PATCH] pstore: avoid recursive spinlocks in the
 oops_in_progress case

> Mm... why break?

We don't know what the back-end driver will do if we allow another call
while a previous one is still in progress.  It might end up corrupting the
backing non-volatile storage and losing some previously saved records.

Existing drivers (ERST and EFI) are dependent on f/w ... so things might
work on some platforms, yet be horribly bad on others.

The patch as it was written converts a deadlock (hang) case into a "lose
this log, but keep going" case. Which seems to be an improvement without
taking any risks about what the backend will do.

-Tony