From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: Generic kernel fails to boot on Alpha bisected to b38d08f3181c Date: Thu, 13 Dec 2018 08:07:24 -0800 Message-ID: <20181213160724.GU2509588@devbig004.ftw2.facebook.com> References: <20181213082612.bi2dcd6uhzp3t6iq@tower> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=VMIvv9oJ+d07z3QLhR1Tb2CkKzGyeqd0I0xBtqS1Vdo=; b=DJCdmOKH4EV3o9DYzEMgupaZtPGPMc3U7+H6RJbn/9fNmfWytE01k2XQA9rg1L1wmt 653dRwOtcYmSO9QX51AbyrqfpbfB1Za+5ibAPxqeMixThQ4Og21n5RvUu7oaRA+w3uz+ Bzs/bgXVdeeLyPjNSY8AY1mnl5dJqSbOQqI2SSxJyLwknRrI+klu7CLG7sdLGOya/u1W W/+aVtAc63k6ks+NMgeGTMLwECt7g3deILYkEbJoicYAIPrHhqU3IJHZnFgUIQvpTLdo b1grkuYz+1nwQpEHm6iRwihqcbe73hhzS7eN7i4A6tU8dG9jBnPXGXMJjtlNx3lScPZQ ZiOw== Content-Disposition: inline In-Reply-To: <20181213082612.bi2dcd6uhzp3t6iq@tower> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Michael Cree , linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, debian-alpha@lists.debian.org Hello, Michael. On Thu, Dec 13, 2018 at 09:26:12PM +1300, Michael Cree wrote: > A kernel built for generic UP Alpha had been noted to fail to boot > for quite some time (since the release of 3.18). The kernel either > locks up before printing any messages to the console or just falls > back into the SRM with a HALT instruction again before any messages > are printed to the console. A work around is to either use a kernel > built for generic SMP or to build a machine specific kernel as these > boot correctly. > > Because there were other compile errors at the time it proved > difficult to bisect, but we are continuing to get complaints about > it as it renders the Debian Alpha installer somewhat useless, so I > returned to trying to find the problem and managed to bisect it to: > > commit b38d08f3181c5025a7ce84646494cc4748492a3b > Author: Tejun Heo > Date: Tue Sep 2 14:46:02 2014 -0400 > > percpu: restructure locking > > Any suggestions as to what might be the problem and a fix? So, the only thing I can think of is that it's calling spin_unlock_irq() while irq handling isn't set up yet. Can you please try the followings? 1. Convert all spin_[un]lock_irq() to spin_lock_irqsave/unlock_irqrestore(). 2. If that still doesn't work, just convert all of them to spin_lock/unlock(), which is obviously broken but still is useful for debugging. Thanks. -- tejun