On 8/12/19 11:36 AM, Andrew F. Davis wrote: > On 8/12/19 12:28 PM, Suman Anna wrote: >> On 8/12/19 10:47 AM, Andrew F. Davis wrote: >>> On 10/23/18 9:19 PM, Suman Anna wrote: >>>> The virtio_rpmsg_bus driver uses the "%p" format-specifier for >>>> printing the vring buffer address. This prints only a hashed >>>> pointer even for previliged users. Use "%pK" instead so that >>>> the address can be printed during debug using kptr_restrict >>>> sysctl. >>>> >>> >>> >>> s/previliged/privileged >> >> Bjorn, >> Can you fix this up when applying. >> >>> >>> You describe what the code does, but not why you need this. %pK is used >>> for only about 1% of pointer printing, why do you want to leak this >>> address to userspace at all? >> >> Andrew, >> Default behavior of %pK is same as %p, but it does allow you to control >> the print. The reason is clearly mentioned in the last sentence in the >> patch description. >> > > > Let me rephrase then, why would you ever set 'kptr_restrict' to anything > other than 0, or why do you want to be able to leak this address to > userspace at all? If the answer is just because you can, then all 12,000 > instances of %p in kernel could be converted for the same reason. It is a dev_dbg statement, so it is already under dynamic debug control. We would only ever use it during debug. regards Suman > > Andrew > > >> regards >> Suman >> >>> >>> Andrew >>> >>> >>>> Signed-off-by: Suman Anna <s-anna@xxxxxx> >>>> --- >>>> drivers/rpmsg/virtio_rpmsg_bus.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c >>>> index f29dee731026..1345f373a1a0 100644 >>>> --- a/drivers/rpmsg/virtio_rpmsg_bus.c >>>> +++ b/drivers/rpmsg/virtio_rpmsg_bus.c >>>> @@ -950,7 +950,7 @@ static int rpmsg_probe(struct virtio_device *vdev) >>>> goto vqs_del; >>>> } >>>> >>>> - dev_dbg(&vdev->dev, "buffers: va %p, dma %pad\n", >>>> + dev_dbg(&vdev->dev, "buffers: va %pK, dma %pad\n", >>>> bufs_va, &vrp->bufs_dma); >>>> >>>> /* half of the buffers is dedicated for RX */ >>>> >>
