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Date: Wed, 25 May 2011 19:00:10 -0400
Message-ID: <BANLkTimuomu=_JuMr7SWrMVvboMX4BX0fA@mail.gmail.com>
Subject: Re: [PATCH] SCSI IOCTL: Check for device deletion [was Re:
 __elv_add_request OOPS]
From: Parag Warudkar <parag.lkml@gmail.com>
To: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Jens Axboe <jaxboe@fusionio.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
        Linux SCSI List <linux-scsi@vger.kernel.org>
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On Wed, May 25, 2011 at 4:52 PM, James Bottomley
<James.Bottomley@hansenpartnership.com> wrote:
> On Wed, 2011-05-25 at 16:42 -0400, Parag Warudkar wrote:
>> Yeah - that makes sense. By that logic, looks like we can only disallow
>> for SDEV_DEL (if we decide to do that check here).
>
> I don't think this is the root cause. ?I think q is non-NULL but has
> already been released, so we're just getting a NULL deref on the actual
> list head.
>
> Does this fix it? ?It adds the refcounting at approximately the correct
> places. ?Of course, we'll now be trying elevator operations on an extant
> queue but one whose elevator functions have been destroyed, so there are
> probably additional state guards to place.

[ Resend with URL - I got a bounce back from vger for attaching the OOPS JPEG ]

It doesn't seem to help. Machine locked up and I was dropped to text
console. I could only capture the oops by a camera.

OOPS available at below URLs [*]

Parag

[*] https://picasaweb.google.com/lh/photo/yccmqaz3xwumwjvecb-b0pTdDOYIfFRksMrZBIo-Inw?feat=directlink

[*] https://picasaweb.google.com/lh/photo/Lim6d3b8p7Lj4D3nHmkbFJTdDOYIfFRksMrZBIo-Inw?feat=directlink
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