On Mon, Oct 16, 2023 at 12:52:59PM +0100, Jean-Philippe Brucker wrote: > On Wed, Oct 04, 2023 at 05:49:45PM -0300, Eduardo Bart wrote: > > I'm experiencing a segmentation fault in lkvm where it may crash after > > powering off a guest machine that uses a virtio network device. > > The crash is hard to reproduce, because looks like it only happens > > when the guest machine is powering off while extra virtio threads is > > doing some work, > > when it happens lkvm crashes in the function virtio_net_rx_thread > > while attempting to read invalid guest physical memory, > > because guest physical memory was unmapped. > > > > I've isolated the problem and looks like when lkvm exits it unmaps the > > guest memory while virtio device extra threads may still be executing. > > I noticed most virtio devices are not executing pthread_cancel + > > pthread_join to synchronize extra threads when exiting, > > to make sure this happens I added explicit calls to the virtio device > > exit function to all virtio devices, > > which should cancel and join all threads before unmapping guest > > physical memory, fixing the crash for me. > > > > Below I'm attaching a patch to fix the issue, feel free to apply or > > fix the issue some other way. > > > > Signed-off-by: Eduardo Bart <edub4rt@xxxxxxxxx> > > The patch doesn't apply for some reason, there seems to be whitespace > issues, tabs replaced by spaces. Eduardo -- please can you send a properly formatted patch addressing Jean-Philippe's comments so that I can apply it? Thanks, Will
