From: Jeff Garzik <jgarzik@pobox.com>
To: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Andrew Vasquez <andrew.vasquez@qlogic.com>,
Linux-SCSI Mailing List <linux-scsi@vger.kernel.org>
Subject: Re: [PATCH] qla2xxx: fix bad locking during eh_abort
Date: Fri, 27 May 2005 16:42:21 -0400 [thread overview]
Message-ID: <4297862D.5070500@pobox.com> (raw)
In-Reply-To: <1117226305.7379.30.camel@mulgrave>
James Bottomley wrote:
> On Fri, 2005-05-27 at 16:30 -0400, Jeff Garzik wrote:
>
>>The ha->hardware_lock is obtained without spin_lock_irq(), so that's
>>correct.
>
>
> Yes, that was my confusion
>
> But ... I wish you hadn't pointed it out. Now I look at the driver, the
> ha->hardware_lock is taken at interrupt level (in the interrupt
> routines).
>
> However, this sequence of code:
>
> spin_unlock_irq(ha->host->host_lock);
> spin_lock(&ha->hardware_lock);
>
> Enables interrupts then takes this lock. If we ever get a qla interrupt
> before we drop the ha->hardware_lock again, that will be a classic
> deadlock.
Agreed, this was my analysis as well.
This driver appears to get locking -backwards-:
it uses spin_lock_irqsave() in interrupt handler.
it does not use spin_lock_irqsave() outside interrupt handler.
IMO this is a 2.6.12-rc issue...
Jeff
next prev parent reply other threads:[~2005-05-27 20:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-26 23:19 [PATCH] qla2xxx: fix bad locking during eh_abort Andrew Vasquez
2005-05-27 20:06 ` James Bottomley
2005-05-27 20:18 ` Andrew Vasquez
2005-05-27 20:30 ` Jeff Garzik
2005-05-27 20:38 ` James Bottomley
2005-05-27 20:42 ` Jeff Garzik [this message]
2005-05-27 22:04 ` Andrew Vasquez
2005-05-27 22:47 ` Jeff Garzik
2005-05-27 20:31 ` James Bottomley
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