On 08/22/2014 07:34 PM, Jan Kara wrote: > On Fri 22-08-14 18:01:09, Hans Verkuil wrote: >> Commit f035eb4e976ef5a059e30bc91cfd310ff030a7d3 (videobuf2: fix lockdep warning) >> unfortunately removed the mmap_sem lock that is needed around the call to >> __qbuf_userptr. Amazingly nobody noticed this until Jan Kara pointed this out >> to me. >> >> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> >> Reported-by: Jan Kara <jack@xxxxxxx> > ... >> @@ -1627,7 +1628,9 @@ static int __buf_prepare(struct vb2_buffer *vb, const struct v4l2_buffer *b) >> ret = __qbuf_mmap(vb, b); >> break; >> case V4L2_MEMORY_USERPTR: > I guess you are missing something like: > > mmap_sem = ¤t->mm->mmap_sem; Insert <red face>. Oops, I'll repost. Regards, Hans > > Honza >> + down_read(mmap_sem); >> ret = __qbuf_userptr(vb, b); >> + up_read(mmap_sem); >> break; >> case V4L2_MEMORY_DMABUF: >> ret = __qbuf_dmabuf(vb, b); >> -- >> 2.0.1 >> -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
