| Message ID | 201207072111.11951.hverkuil@xs4all.nl (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi, On 07/07/2012 09:11 PM, Hans Verkuil wrote: > On Sat July 7 2012 20:46:21 Hans de Goede wrote: >> Commit efbceecd4522a41b8442c6b4f68b4508d57d1ccf, adds a number of helper >> functions for ctrl related ioctls to v4l2-ioctl.c, these helpers assume that >> if file->private_data != NULL, it points to a v4l2_fh, which is only the case >> for drivers which actually use v4l2_fh. >> >> This breaks for example bttv which use the "filedata" pointer for its own uses, >> and now all the ctrl ioctls try to use whatever its filedata points to as >> v4l2_fh and think it has a ctrl_handler, leading to: >> >> [ 142.499214] BUG: unable to handle kernel NULL pointer dereference at 0000000000000021 >> [ 142.499270] IP: [<ffffffffa01cb959>] v4l2_queryctrl+0x29/0x230 [videodev] >> [ 142.514649] [<ffffffffa01c7a77>] v4l_queryctrl+0x47/0x90 [videodev] >> [ 142.517417] [<ffffffffa01c58b1>] __video_do_ioctl+0x2c1/0x420 [videodev] >> [ 142.520116] [<ffffffffa01c7ee6>] video_usercopy+0x1a6/0x470 [videodev] >> ... >> >> This patch adds the missing test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) tests >> to the ctrl ioctl helpers v4l2_fh paths, fixing the issues with for example >> the bttv driver. > > Urgh, I didn't test with a 'old' driver. Thanks for catching this. But I would > prefer a simpler patch (although effectively the same) like this: > > diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c > index 70e0efb..bbcb4f6 100644 > --- a/drivers/media/video/v4l2-ioctl.c > +++ b/drivers/media/video/v4l2-ioctl.c > @@ -1486,7 +1486,7 @@ static int v4l_queryctrl(const struct v4l2_ioctl_ops *ops, > { > struct video_device *vfd = video_devdata(file); > struct v4l2_queryctrl *p = arg; > - struct v4l2_fh *vfh = fh; > + struct v4l2_fh *vfh = test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL; > > if (vfh && vfh->ctrl_handler) > return v4l2_queryctrl(vfh->ctrl_handler, p); <snip> I agree that that is better, so I've added that version to my tree now, for which I expect / hope to send a pullreq later tonight. Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c index 70e0efb..bbcb4f6 100644 --- a/drivers/media/video/v4l2-ioctl.c +++ b/drivers/media/video/v4l2-ioctl.c @@ -1486,7 +1486,7 @@ static int v4l_queryctrl(const struct v4l2_ioctl_ops *ops, { struct video_device *vfd = video_devdata(file); struct v4l2_queryctrl *p = arg; - struct v4l2_fh *vfh = fh; + struct v4l2_fh *vfh = test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL; if (vfh && vfh->ctrl_handler) return v4l2_queryctrl(vfh->ctrl_handler, p); @@ -1502,7 +1502,7 @@ static int v4l_querymenu(const struct v4l2_ioctl_ops *ops, { struct video_device *vfd = video_devdata(file); struct v4l2_querymenu *p = arg; - struct v4l2_fh *vfh = fh; + struct v4l2_fh *vfh = test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL; if (vfh && vfh->ctrl_handler) return v4l2_querymenu(vfh->ctrl_handler, p); @@ -1518,7 +1518,7 @@ static int v4l_g_ctrl(const struct v4l2_ioctl_ops *ops, { struct video_device *vfd = video_devdata(file); struct v4l2_control *p = arg; - struct v4l2_fh *vfh = fh; + struct v4l2_fh *vfh = test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL; struct v4l2_ext_controls ctrls; struct v4l2_ext_control ctrl; @@ -1551,7 +1551,7 @@ static int v4l_s_ctrl(const struct v4l2_ioctl_ops *ops, { struct video_device *vfd = video_devdata(file); struct v4l2_control *p = arg; - struct v4l2_fh *vfh = fh; + struct v4l2_fh *vfh = test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL; struct v4l2_ext_controls ctrls; struct v4l2_ext_control ctrl; @@ -1579,7 +1579,7 @@ static int v4l_g_ext_ctrls(const struct v4l2_ioctl_ops *ops, { struct video_device *vfd = video_devdata(file); struct v4l2_ext_controls *p = arg; - struct v4l2_fh *vfh = fh; + struct v4l2_fh *vfh = test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL; p->error_idx = p->count; if (vfh && vfh->ctrl_handler) @@ -1597,7 +1597,7 @@ static int v4l_s_ext_ctrls(const struct v4l2_ioctl_ops *ops, { struct video_device *vfd = video_devdata(file); struct v4l2_ext_controls *p = arg; - struct v4l2_fh *vfh = fh; + struct v4l2_fh *vfh = test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL; p->error_idx = p->count; if (vfh && vfh->ctrl_handler) @@ -1615,7 +1615,7 @@ static int v4l_try_ext_ctrls(const struct v4l2_ioctl_ops *ops, { struct video_device *vfd = video_devdata(file); struct v4l2_ext_controls *p = arg; - struct v4l2_fh *vfh = fh; + struct v4l2_fh *vfh = test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL; p->error_idx = p->count; if (vfh && vfh->ctrl_handler)