virtio: console: add locking around c_ovq operations
When multiple ovq operations are being performed (lots of open/close operations on virtio_console fds), the __send_control_msg() function can get confused without locking. A simple recipe to cause badness is: * create a QEMU VM with two virtio-serial ports * in the guest, do while true;do echo abc >/dev/vport0p1;done while true;do echo edf >/dev/vport0p2;done In one run, this caused a panic in __send_control_msg(). In another, I got virtio_console virtio0: control-o:id 0 is not a head! This also results repeated messages similar to these on the host: qemu-kvm: virtio-serial-bus: Unexpected port id 478762112 for device virtio-serial-bus.0 qemu-kvm: virtio-serial-bus: Unexpected port id 478762368 for device virtio-serial-bus.0 Reported-by:FuXiangChun <xfu@redhat.com> Signed-off-by:
Amit Shah <amit.shah@redhat.com> Reviewed-by:
Wanlong Gao <gaowanlong@cn.fujitsu.com> Reviewed-by:
Asias He <asias@redhat.com> Signed-off-by:
Rusty Russell <rusty@rustcorp.com.au> Cc: stable@kernel.org
parent
165b1b8b
Please register or sign in to comment