linux-kernel - Re: [PATCH 0/2] genirq/affinity: try to make sure online CPU is assgined to irq vector

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20180116122323.GB26429@ming.t460p>
Date:   Tue, 16 Jan 2018 20:23:24 +0800
From:   Ming Lei <ming.lei@...hat.com>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Christoph Hellwig <hch@...radead.org>, Jens Axboe <axboe@...com>,
        linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        Laurence Oberman <loberman@...hat.com>,
        Mike Snitzer <snitzer@...hat.com>,
        Don Brace <don.brace@...rosemi.com>,
        "James E.J. Bottomley" <jejb@...ux.vnet.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        esc.storagedev@...rosemi.com, linux-scsi@...r.kernel.org
Subject: Re: [PATCH 0/2] genirq/affinity: try to make sure online CPU is
 assgined to irq vector

On Tue, Jan 16, 2018 at 12:25:19PM +0100, Thomas Gleixner wrote:
> On Tue, 16 Jan 2018, Ming Lei wrote:
> 
> > On Mon, Jan 15, 2018 at 09:40:36AM -0800, Christoph Hellwig wrote:
> > > On Tue, Jan 16, 2018 at 12:03:43AM +0800, Ming Lei wrote:
> > > > Hi,
> > > > 
> > > > These two patches fixes IO hang issue reported by Laurence.
> > > > 
> > > > 84676c1f21 ("genirq/affinity: assign vectors to all possible CPUs")
> > > > may cause one irq vector assigned to all offline CPUs, then this vector
> > > > can't handle irq any more.
> > > 
> > > Well, that very much was the intention of managed interrupts.  Why
> > > does the device raise an interrupt for a queue that has no online
> > > cpu assigned to it?
> > 
> > It is because of irq_create_affinity_masks().
> 
> That still does not answer the question. If the interrupt for a queue is
> assigned to an offline CPU, then the queue should not be used and never
> raise an interrupt. That's how managed interrupts have been designed.

Sorry for not answering it in 1st place, but later I realized that:

	https://marc.info/?l=linux-block&m=151606896601195&w=2

Also wrt. HPSA's queue, looks they are not usual IO queue(such as NVMe's
hw queue) which supposes to be C/S model. And HPSA's queue is more like
a management queue, I guess, since HPSA is still a single queue HBA,
from blk-mq view.

Cc HPSA and SCSI guys.

Thanks,
Ming