On Tue, 23 Feb 2021 at 17:43, Michael S. Tsirkin <mst@xxxxxxxxxx> wrote: > > On Tue, Feb 23, 2021 at 03:30:45PM +0530, Gautam Dawar wrote: > > When qemu with vhost-vdpa netdevice is run for the first time, it works well. > > But after the VM is powered off, the next qemu run causes kernel panic due to a > > NULL pointer dereference in irq_bypass_register_producer(). > > > > When the VM is powered off, vhost_vdpa_clean_irq() misses on calling > > irq_bypass_unregister_producer() for irq 0 because of the existing check. > > > > This leaves stale producer nodes, which are reset in vhost_vring_call_reset() > > when vhost_dev_init() is invoked during the second qemu run. > > > > As the node member of struct irq_bypass_producer is also initialized > > to zero, traversal on the producers list causes crash due to NULL pointer > > dereference. > > > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=211711 > > Signed-off-by: Gautam Dawar <gdawar@xxxxxxxxxx> > > Could you please repost without HTML? Otherwise git am fails on this patch: > > error: corrupt patch at line 6 > error: could not build fake ancestor > Patch failed at 0001 vhost vdpa: fix the missing irq_bypass_unregister_producer() invocation > > Also, which commit introduces the bug? A Fixes: tag would be helpful. > > Thanks! > I've added the fixes tag and submitted patch v3 in plain-text format. Thanks, Gautam > > ----- > > changelog: > > v1->v2: > > - Addressed Jason's comment to remove the irq check and use > > vhost_vdpa_unsetup_vq_irq() to avoid local variable vq > > ----- > > > > > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > > index 62a9bb0efc55..e00573b87aba 100644 > > --- a/drivers/vhost/vdpa.c > > +++ b/drivers/vhost/vdpa.c > > @@ -844,14 +844,10 @@ static int vhost_vdpa_open(struct inode *inode, struct > > file *filep) > > > > static void vhost_vdpa_clean_irq(struct vhost_vdpa *v) > > { > > - struct vhost_virtqueue *vq; > > int i; > > > > - for (i = 0; i < v->nvqs; i++) { > > - vq = &v->vqs[i]; > > - if (vq->call_ctx.producer.irq) > > - irq_bypass_unregister_producer(&vq->call_ctx.producer); > > - } > > + for (i = 0; i < v->nvqs; i++) > > + vhost_vdpa_unsetup_vq_irq(v, i); > > } > > > > static int vhost_vdpa_release(struct inode *inode, struct file *filep) > _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
