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authorChristof Schmitt <christof.schmitt@de.ibm.com>2009-09-17 09:10:14 +0200
committerJames Bottomley <James.Bottomley@suse.de>2009-10-02 09:45:58 -0500
commite27168f8c337b12b8aa8d59c3123c79d2f83603d (patch)
tree947d5e483ca1d4ee0bbbbdc7abf317f1f591dbd0 /drivers/scsi/sg.c
parent5915136d4d3954867cced8a2297bddd16caf36a1 (diff)
downloadlinux-e27168f8c337b12b8aa8d59c3123c79d2f83603d.tar.bz2
[SCSI] sg: Free data buffers after calling blk_rq_unmap_user
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> Acked-by: Douglas Gilbert <dgilbert@interlog.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Diffstat (limited to 'drivers/scsi/sg.c')
-rw-r--r--drivers/scsi/sg.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 0cb049f5cc56..a328b5f284de 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1708,11 +1708,6 @@ static int sg_finish_rem_req(Sg_request * srp)
Sg_scatter_hold *req_schp = &srp->data;
SCSI_LOG_TIMEOUT(4, printk("sg_finish_rem_req: res_used=%d\n", (int) srp->res_used));
- if (srp->res_used)
- sg_unlink_reserve(sfp, srp);
- else
- sg_remove_scat(req_schp);
-
if (srp->rq) {
if (srp->bio)
ret = blk_rq_unmap_user(srp->bio);
@@ -1720,6 +1715,11 @@ static int sg_finish_rem_req(Sg_request * srp)
blk_put_request(srp->rq);
}
+ if (srp->res_used)
+ sg_unlink_reserve(sfp, srp);
+ else
+ sg_remove_scat(req_schp);
+
sg_remove_request(sfp, srp);
return ret;