| Message ID | 20200307130720.16652-1-mans@mansr.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | usb: musb: fix crash with highmen PIO and usbmon | expand |
Hi Mans, On Sat, Mar 07, 2020 at 01:07:20PM +0000, Mans Rullgard wrote: > When handling a PIO bulk transfer with highmem buffer, a temporary > mapping is assigned to urb->transfer_buffer. After the transfer is > complete, an invalid address is left behind in this pointer. This is > not ordinarily a problem since nothing touches that buffer before the > urb is released. However, when usbmon is active, usbmon_urb_complete() > calls (indirectly) mon_bin_get_data() which does access the transfer > buffer if it is set. To prevent an invalid memory access here, reset > urb->tranfer_buffer to NULL when finished. > > Fixes: 8e8a55165469 ("usb: musb: host: Handle highmem in PIO mode") > Signed-off-by: Mans Rullgard <mans@mansr.com> Thanks for fixing the bug. > --- > drivers/usb/musb/musb_host.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c > index 1c813c37462a..b67b40de1947 100644 > --- a/drivers/usb/musb/musb_host.c > +++ b/drivers/usb/musb/musb_host.c > @@ -1459,8 +1459,10 @@ void musb_host_tx(struct musb *musb, u8 epnum) > qh->segsize = length; > > if (qh->use_sg) { > - if (offset + length >= urb->transfer_buffer_length) > + if (offset + length >= urb->transfer_buffer_length) { > qh->use_sg = false; > + urb->transfer_buffer = NULL; > + } In this tx case, can you directly pass qh->sg_miter.addr to musb_write_fifo() so that urb->transfer_buffer is not touched at all? -Bin.
Bin Liu <b-liu@ti.com> writes: > Hi Mans, > > On Sat, Mar 07, 2020 at 01:07:20PM +0000, Mans Rullgard wrote: >> When handling a PIO bulk transfer with highmem buffer, a temporary >> mapping is assigned to urb->transfer_buffer. After the transfer is >> complete, an invalid address is left behind in this pointer. This is >> not ordinarily a problem since nothing touches that buffer before the >> urb is released. However, when usbmon is active, usbmon_urb_complete() >> calls (indirectly) mon_bin_get_data() which does access the transfer >> buffer if it is set. To prevent an invalid memory access here, reset >> urb->tranfer_buffer to NULL when finished. >> >> Fixes: 8e8a55165469 ("usb: musb: host: Handle highmem in PIO mode") >> Signed-off-by: Mans Rullgard <mans@mansr.com> > > Thanks for fixing the bug. > >> --- >> drivers/usb/musb/musb_host.c | 8 ++++++-- >> 1 file changed, 6 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c >> index 1c813c37462a..b67b40de1947 100644 >> --- a/drivers/usb/musb/musb_host.c >> +++ b/drivers/usb/musb/musb_host.c >> @@ -1459,8 +1459,10 @@ void musb_host_tx(struct musb *musb, u8 epnum) >> qh->segsize = length; >> >> if (qh->use_sg) { >> - if (offset + length >= urb->transfer_buffer_length) >> + if (offset + length >= urb->transfer_buffer_length) { >> qh->use_sg = false; >> + urb->transfer_buffer = NULL; >> + } > > In this tx case, can you directly pass qh->sg_miter.addr to > musb_write_fifo() so that urb->transfer_buffer is not touched at all? Yes, that seems to work. I'll prepare a new patch.
diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c index 1c813c37462a..b67b40de1947 100644 --- a/drivers/usb/musb/musb_host.c +++ b/drivers/usb/musb/musb_host.c @@ -1459,8 +1459,10 @@ void musb_host_tx(struct musb *musb, u8 epnum) qh->segsize = length; if (qh->use_sg) { - if (offset + length >= urb->transfer_buffer_length) + if (offset + length >= urb->transfer_buffer_length) { qh->use_sg = false; + urb->transfer_buffer = NULL; + } } musb_ep_select(mbase, epnum); @@ -1977,8 +1979,10 @@ void musb_host_rx(struct musb *musb, u8 epnum) urb->actual_length += xfer_len; qh->offset += xfer_len; if (done) { - if (qh->use_sg) + if (qh->use_sg) { qh->use_sg = false; + urb->transfer_buffer = NULL; + } if (urb->status == -EINPROGRESS) urb->status = status;
When handling a PIO bulk transfer with highmem buffer, a temporary mapping is assigned to urb->transfer_buffer. After the transfer is complete, an invalid address is left behind in this pointer. This is not ordinarily a problem since nothing touches that buffer before the urb is released. However, when usbmon is active, usbmon_urb_complete() calls (indirectly) mon_bin_get_data() which does access the transfer buffer if it is set. To prevent an invalid memory access here, reset urb->tranfer_buffer to NULL when finished. Fixes: 8e8a55165469 ("usb: musb: host: Handle highmem in PIO mode") Signed-off-by: Mans Rullgard <mans@mansr.com> --- drivers/usb/musb/musb_host.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)