| Message ID | 20210609215833.30393-1-paskripkin@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | can: mcba_usb: fix memory leak in mcba_usb | expand |
On 10.06.2021 00:58:33, Pavel Skripkin wrote: > Syzbot reported memory leak in SocketCAN driver > for Microchip CAN BUS Analyzer Tool. The problem > was in unfreed usb_coherent. > > In mcba_usb_start() 20 coherent buffers are allocated > and there is nothing, that frees them: > > 1) In callback function the urb is resubmitted and that's all > 2) In disconnect function urbs are simply killed, but > URB_FREE_BUFFER is not set (see mcba_usb_start) > and this flag cannot be used with coherent buffers. > > Fail log: > [ 1354.053291][ T8413] mcba_usb 1-1:0.0 can0: device disconnected > [ 1367.059384][ T8420] kmemleak: 20 new suspected memory leaks (see /sys/kernel/debug/kmem) > > So, all allocated buffers should be freed with usb_free_coherent() > explicitly > > NOTE: > The same pattern for allocating and freeing coherent buffers > is used in drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c > > Fixes: 51f3baad7de9 ("can: mcba_usb: Add support for Microchip CAN BUS Analyzer") > Reported-and-tested-by: syzbot+57281c762a3922e14dfe@syzkaller.appspotmail.com > Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> Applied to linux-can/testing. Tnx, Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
diff --git a/drivers/net/can/usb/mcba_usb.c b/drivers/net/can/usb/mcba_usb.c index 029e77dfa773..a45865bd7254 100644 --- a/drivers/net/can/usb/mcba_usb.c +++ b/drivers/net/can/usb/mcba_usb.c @@ -82,6 +82,8 @@ struct mcba_priv { bool can_ka_first_pass; bool can_speed_check; atomic_t free_ctx_cnt; + void *rxbuf[MCBA_MAX_RX_URBS]; + dma_addr_t rxbuf_dma[MCBA_MAX_RX_URBS]; }; /* CAN frame */ @@ -633,6 +635,7 @@ static int mcba_usb_start(struct mcba_priv *priv) for (i = 0; i < MCBA_MAX_RX_URBS; i++) { struct urb *urb = NULL; u8 *buf; + dma_addr_t buf_dma; /* create a URB, and a buffer for it */ urb = usb_alloc_urb(0, GFP_KERNEL); @@ -642,7 +645,7 @@ static int mcba_usb_start(struct mcba_priv *priv) } buf = usb_alloc_coherent(priv->udev, MCBA_USB_RX_BUFF_SIZE, - GFP_KERNEL, &urb->transfer_dma); + GFP_KERNEL, &buf_dma); if (!buf) { netdev_err(netdev, "No memory left for USB buffer\n"); usb_free_urb(urb); @@ -661,11 +664,14 @@ static int mcba_usb_start(struct mcba_priv *priv) if (err) { usb_unanchor_urb(urb); usb_free_coherent(priv->udev, MCBA_USB_RX_BUFF_SIZE, - buf, urb->transfer_dma); + buf, buf_dma); usb_free_urb(urb); break; } + priv->rxbuf[i] = buf; + priv->rxbuf_dma[i] = buf_dma; + /* Drop reference, USB core will take care of freeing it */ usb_free_urb(urb); } @@ -708,7 +714,14 @@ static int mcba_usb_open(struct net_device *netdev) static void mcba_urb_unlink(struct mcba_priv *priv) { + int i; + usb_kill_anchored_urbs(&priv->rx_submitted); + + for (i = 0; i < MCBA_MAX_RX_URBS; ++i) + usb_free_coherent(priv->udev, MCBA_USB_RX_BUFF_SIZE, + priv->rxbuf[i], priv->rxbuf_dma[i]); + usb_kill_anchored_urbs(&priv->tx_submitted); }
Syzbot reported memory leak in SocketCAN driver for Microchip CAN BUS Analyzer Tool. The problem was in unfreed usb_coherent. In mcba_usb_start() 20 coherent buffers are allocated and there is nothing, that frees them: 1) In callback function the urb is resubmitted and that's all 2) In disconnect function urbs are simply killed, but URB_FREE_BUFFER is not set (see mcba_usb_start) and this flag cannot be used with coherent buffers. Fail log: [ 1354.053291][ T8413] mcba_usb 1-1:0.0 can0: device disconnected [ 1367.059384][ T8420] kmemleak: 20 new suspected memory leaks (see /sys/kernel/debug/kmem) So, all allocated buffers should be freed with usb_free_coherent() explicitly NOTE: The same pattern for allocating and freeing coherent buffers is used in drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c Fixes: 51f3baad7de9 ("can: mcba_usb: Add support for Microchip CAN BUS Analyzer") Reported-and-tested-by: syzbot+57281c762a3922e14dfe@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> --- drivers/net/can/usb/mcba_usb.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-)