On Mon, Mar 28, 2022 at 10:44:52AM +0200, Fabio M. De Francesco wrote: > Currently, if device_add() or device_add_disk() fail, the code jumps to > the "out" label. Doing so we get a memory leak as Syzbot reports.[1] > > Fix this bug by jumping to the "out_free_index" label. > > [1] https://groups.google.com/g/syzkaller-bugs/c/BvuqG6YGb6I > > Reported-and-tested-by: syzbot+f08c77040fa163a75a46@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: 2a7a891f4c40 ("scsi: sd: Add error handling support for add_disk()") > Fixes: 265dfe8ebbab ("scsi: sd: Free scsi_disk device via put_device()") > Signed-off-by: Fabio M. De Francesco <fmdefrancesco@xxxxxxxxx> > --- > drivers/scsi/sd.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > index a390679cf458..61fcf653ef5a 100644 > --- a/drivers/scsi/sd.c > +++ b/drivers/scsi/sd.c > @@ -3434,7 +3434,7 @@ static int sd_probe(struct device *dev) > error = device_add(&sdkp->disk_dev); > if (error) { > put_device(&sdkp->disk_dev); > - goto out; > + goto out_free_index; The put_device calls scsi_disk_release() so this change will introduce use after frees and double frees. There is a larger process issue here. We need to figure out why syzbot did not detect that this patch introduces bugs. regards, dan carpenter
