On Thu, Sep 17, 2009 at 03:00:44PM +0900, FUJITA Tomonori wrote: > Sorry for the delay, > > On Tue, 15 Sep 2009 18:53:57 +0200 > Christof Schmitt <christof.schmitt@xxxxxxxxxx> wrote: > > > This patch fixes a problem with the sg driver that is only visible > > with the CONFIG_DEBUG_PAGEALLOC kernel config option. The patch works > > for me, but i would appreciate the review of somebody with more > > knowledge about the interactions between the sg driver and the block > > layer. > > > > Christof > > --- > > sg: Free data buffers after calling blk_rq_unmap_user > > > > From: Christof Schmitt <christof.schmitt@xxxxxxxxxx> > > > > 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. > > > > Signed-off-by: Christof Schmitt <christof.schmitt@xxxxxxxxxx> > > --- > > drivers/scsi/sg.c | 10 +++++----- > > 1 file changed, 5 insertions(+), 5 deletions(-) > > Oops, thanks a lot! > > Acked-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> > > It would be better to add "Cc: stable@xxxxxxxxxx" tag since this fix > needs to be sent to stable trees. Thanks for the review. I will resend the patch with the added acked-by and cc. -- Christof -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
