From: Douglas Gilbert <dgilbert@interlog.com>
To: Christof Schmitt <christof.schmitt@de.ibm.com>
Cc: James Bottomley <James.Bottomley@suse.de>,
linux-scsi@vger.kernel.org,
FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
stable@kernel.org
Subject: Re: [patch 1/1] sg: Free data buffers after calling blk_rq_unmap_user
Date: Thu, 17 Sep 2009 10:06:01 +0200 [thread overview]
Message-ID: <4AB1EDE9.8090102@interlog.com> (raw)
In-Reply-To: <20090917071553.766054000@de.ibm.com>
Christof Schmitt wrote:
> From: Christof Schmitt <christof.schmitt@de.ibm.com>
>
> Running sg_luns on s390x with CONFIG_DEBUG_PAGEALLOC enabled fails
> with EFAULT from the SG_IO ioctl. The EFAULT is the result from
> copy_to_user failing in this call chain:
>
> sg_ioctl
> sg_new_read
> sg_finish_rem_req
> blk_rq_unmap_user
> __blk_rq_unmap_user
> bio_uncopy_user
> __bio_copy_iov
> copy_to_user
>
> The sg driver calls sg_remove_scat to free the memory pages before
> calling blk_rq_unmap_user that tries to copy the data back to
> userspace. Change the order to first call blk_rq_unmap_user before
> freeing the pages in sg_remove_scat.
>
> Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
> Cc: stable@kernel.org
> Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
prev parent reply other threads:[~2009-09-17 8:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-17 7:10 [patch 0/1] Fix data buffer handling in sg driver Christof Schmitt
2009-09-17 7:10 ` [patch 1/1] sg: Free data buffers after calling blk_rq_unmap_user Christof Schmitt
2009-09-17 8:06 ` Douglas Gilbert [this message]
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