From 7a3ed2d95e9ef3032700c2e56f3369d8652a6e8b Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Sat, 7 Jul 2012 16:11:11 -0300 Subject: [PATCH] [media] v4l2-ioctl: Don't assume file->private_data always points to a v4l2_fh 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: [] v4l2_queryctrl+0x29/0x230 [videodev] [ 142.514649] [] v4l_queryctrl+0x47/0x90 [videodev] [ 142.517417] [] __video_do_ioctl+0x2c1/0x420 [videodev] [ 142.520116] [] 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. Signed-off-by: Hans Verkuil Signed-off-by: Hans de Goede Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/v4l2-ioctl.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c index 17dff312d76d..68d89eadf1ca 100644 --- a/drivers/media/video/v4l2-ioctl.c +++ b/drivers/media/video/v4l2-ioctl.c @@ -1486,7 +1486,8 @@ 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 +1503,8 @@ 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 +1520,8 @@ 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 +1554,8 @@ 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 +1583,8 @@ 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 +1602,8 @@ 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 +1621,8 @@ 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)