On Thu, Oct 03, 2019 at 07:59:33PM -0500, joshua stein wrote: > On Fri, 04 Oct 2019 at 01:05:12 +0200, Solene Rapenne wrote: > > I found this line just before writing a gigantic core file > > > > 52304 firefox CALL ioctl(124,VIDIOC_QUERYCAP,0x1d9a1d7ac158) > > > > I'm not sure what I need to search for the fd, I found these lines > > related to "124". > > > > 52304 firefox NAMI "/dev/video0" > > 52304 firefox GIO fd 4 wrote 4096 bytes > > > > "\0\0\0\M^?\0\0\0\M^?\0\0\0\M^?\0\0\0\M^?\0\0\0\M^?\0\0\0\M^?\0\0\0\M^?\0\0\0\M^?\0\0\0\M^?\0\0\ > > [ lot of this ] > > 52304 firefox RET open 124/0x7c > > > > I'm guessing this is the main process since the content process > can't open /dev/video, but if you grep the kdump output for > "52304.*pledge" it will show what file it read its promises from. > Then you can add the video pledge to that file and see if it fixes > the crash. > > But perhaps it's stranger that Firefox is trying to read your webcam > information just by viewing a YouTube video...
The browser is trying to access the webcam because a page called in GetUserMedia/WebRTC APIs to figure out if a webcam is available.. Afaict, firefox itself makes no decisions - the websites authors do.
