Put a WARN_ON in __blk_put_request if it is about to
leak bio(s). This is a serious bug that can happen in error
handling code paths.
For this to work I have fixed a couple of places in block/ where
request->bio != NULL ownership was not honored. And a small cleanup
at sg_io() while at it.
Signed-off-by: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
---
block/blk-core.c | 3 +++
block/blk-merge.c | 2 ++
block/scsi_ioctl.c | 21 ++++-----------------
3 files changed, 9 insertions(+), 17 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index f9118c0..b3aabdd 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1031,6 +1031,9 @@ void __blk_put_request(struct request_queue *q, struct request *req)
elv_completed_request(q, req);
+ /* this is a bio leak */
+ WARN_ON(req->bio != NULL);
+
/*
* Request may not have originated from ll_rw_blk. if not,
* it didn't come out of our reserved rq pools
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 5a244f0..e39cb24 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -403,6 +403,8 @@ static int attempt_merge(struct request_queue *q, struct request *req,
if (blk_rq_cpu_valid(next))
req->cpu = next->cpu;
+ /* owner-ship of bio passed from next to req */
+ next->bio = NULL;
__blk_put_request(q, next);
return 1;
}
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index ee9c67d..626ee27 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -214,21 +214,10 @@ static int blk_fill_sghdr_rq(struct request_queue *q, struct request *rq,
return 0;
}
-/*
- * unmap a request that was previously mapped to this sg_io_hdr. handles
- * both sg and non-sg sg_io_hdr.
- */
-static int blk_unmap_sghdr_rq(struct request *rq, struct sg_io_hdr *hdr)
-{
- blk_rq_unmap_user(rq->bio);
- blk_put_request(rq);
- return 0;
-}
-
static int blk_complete_sghdr_rq(struct request *rq, struct sg_io_hdr *hdr,
struct bio *bio)
{
- int r, ret = 0;
+ int ret = 0;
/*
* fill in all the output members
@@ -253,12 +242,10 @@ static int blk_complete_sghdr_rq(struct request *rq, struct sg_io_hdr *hdr,
ret = -EFAULT;
}
- rq->bio = bio;
- r = blk_unmap_sghdr_rq(rq, hdr);
- if (ret)
- r = ret;
+ blk_rq_unmap_user(bio);
+ blk_put_request(rq);
- return r;
+ return ret;
}
static int sg_io(struct request_queue *q, struct gendisk *bd_disk,
--
1.6.2.1
--
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