Messages in this thread | | | Date | Mon, 11 Nov 2013 10:48:00 +0100 | From | Roger Pau Monné <> | Subject | Re: [Xen-devel] [PATCH] block: xen-blkfront: Fix possible NULL ptr dereference |
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On 09/11/13 16:36, Felipe Pena wrote: > In the blkif_release function the bdget_disk() call might returns > a NULL ptr which might be dereferenced on bdev->bd_openers checking > > Signed-off-by: Felipe Pena <felipensp@gmail.com> > --- > drivers/block/xen-blkfront.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c > index a4660bb..7bb1552 100644 > --- a/drivers/block/xen-blkfront.c > +++ b/drivers/block/xen-blkfront.c > @@ -1959,6 +1959,9 @@ static void blkif_release(struct gendisk *disk, fmode_t mode) > > bdev = bdget_disk(disk, 0); > > + if (!bdev) > + goto out_mutex;
Is this actually possible? By looking at blkfront code, it seems like we don't remove the device if it is still open, so maybe this should be a BUG_ON instead of failing silently.
Roger.
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