Em Mon, 25 Feb 2013 01:39:41 +0200
Antti Palosaari <cr...@iki.fi> escreveu:
> WARNING: at lib/dma-debug.c:947 check_for_stack+0xa7/0xf0()
> ehci-pci 0000:00:04.1: DMA-API: device driver maps memory fromstack
>
> Reported-by: poma <pomidorabelis...@gmail.com>
> Signed-off-by: Antti Palosaari <cr...@iki.fi>
> ---
> drivers/media/usb/dvb-usb-v2/af9015.c | 34 ++++++++++++++++------------------
> drivers/media/usb/dvb-usb-v2/af9015.h | 2 ++
> 2 files changed, 18 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/media/usb/dvb-usb-v2/af9015.c
> b/drivers/media/usb/dvb-usb-v2/af9015.c
> index b86d0f2..28983aa 100644
> --- a/drivers/media/usb/dvb-usb-v2/af9015.c
> +++ b/drivers/media/usb/dvb-usb-v2/af9015.c
> @@ -30,22 +30,20 @@ DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
>
> static int af9015_ctrl_msg(struct dvb_usb_device *d, struct req_t *req)
> {
> -#define BUF_LEN 63
> #define REQ_HDR_LEN 8 /* send header size */
> #define ACK_HDR_LEN 2 /* rece header size */
> struct af9015_state *state = d_to_priv(d);
> int ret, wlen, rlen;
> - u8 buf[BUF_LEN];
> u8 write = 1;
>
> - buf[0] = req->cmd;
> - buf[1] = state->seq++;
> - buf[2] = req->i2c_addr;
> - buf[3] = req->addr >> 8;
> - buf[4] = req->addr & 0xff;
> - buf[5] = req->mbox;
> - buf[6] = req->addr_len;
> - buf[7] = req->data_len;
> + state->buf[0] = req->cmd;
> + state->buf[1] = state->seq++;
> + state->buf[2] = req->i2c_addr;
> + state->buf[3] = req->addr >> 8;
> + state->buf[4] = req->addr & 0xff;
> + state->buf[5] = req->mbox;
> + state->buf[6] = req->addr_len;
> + state->buf[7] = req->data_len;
>
> switch (req->cmd) {
> case GET_CONFIG:
> @@ -55,14 +53,14 @@ static int af9015_ctrl_msg(struct dvb_usb_device *d,
> struct req_t *req)
> break;
> case READ_I2C:
> write = 0;
> - buf[2] |= 0x01; /* set I2C direction */
> + state->buf[2] |= 0x01; /* set I2C direction */
> case WRITE_I2C:
> - buf[0] = READ_WRITE_I2C;
> + state->buf[0] = READ_WRITE_I2C;
> break;
> case WRITE_MEMORY:
> if (((req->addr & 0xff00) == 0xff00) ||
> ((req->addr & 0xff00) == 0xae00))
> - buf[0] = WRITE_VIRTUAL_MEMORY;
> + state->buf[0] = WRITE_VIRTUAL_MEMORY;
> case WRITE_VIRTUAL_MEMORY:
> case COPY_FIRMWARE:
> case DOWNLOAD_FIRMWARE:
> @@ -90,7 +88,7 @@ static int af9015_ctrl_msg(struct dvb_usb_device *d, struct
> req_t *req)
> rlen = ACK_HDR_LEN;
> if (write) {
> wlen += req->data_len;
> - memcpy(&buf[REQ_HDR_LEN], req->data, req->data_len);
> + memcpy(&state->buf[REQ_HDR_LEN], req->data, req->data_len);
> } else {
> rlen += req->data_len;
> }
> @@ -99,21 +97,21 @@ static int af9015_ctrl_msg(struct dvb_usb_device *d,
> struct req_t *req)
> if (req->cmd == DOWNLOAD_FIRMWARE || req->cmd == RECONNECT_USB)
> rlen = 0;
>
> - ret = dvb_usbv2_generic_rw(d, buf, wlen, buf, rlen);
> + ret = dvb_usbv2_generic_rw(d, state->buf, wlen, state->buf, rlen);
> if (ret)
> goto error;
>
> /* check status */
> - if (rlen && buf[1]) {
> + if (rlen && state->buf[1]) {
> dev_err(&d->udev->dev, "%s: command failed=%d\n",
> - KBUILD_MODNAME, buf[1]);
> + KBUILD_MODNAME, state->buf[1]);
> ret = -EIO;
> goto error;
> }
>
> /* read request, copy returned data to return buf */
> if (!write)
> - memcpy(req->data, &buf[ACK_HDR_LEN], req->data_len);
> + memcpy(req->data, &state->buf[ACK_HDR_LEN], req->data_len);
Now that you're using just one buffer here, you'll need to protect this
routine with a mutex, as af9015_rc_query() may be called by a kthread
while af9015_ctrl_msg() is running. As the RC polling code will also call
af9015_ctrl_msg() and both will be filling the very same state->buf, a
race condition happens.
--
Cheers,
Mauro
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
