4.4-stable review patch. If anyone has any objections, please let me know.
------------------ [ Upstream commit 3ccb4fd8f492f99aece21acc1bd6142275f26236 ] clocksource_change_rating() involves mutex usage and can't be called in interrupt context. It also makes sense to avoid doing redundant work on crash. Signed-off-by: Vitaly Kuznetsov <[email protected]> Signed-off-by: K. Y. Srinivasan <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/hv/hv.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -293,8 +293,14 @@ void hv_cleanup(void) * Cleanup the TSC page based CS. */ if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) { - clocksource_change_rating(&hyperv_cs_tsc, 10); - clocksource_unregister(&hyperv_cs_tsc); + /* + * Crash can happen in an interrupt context and unregistering + * a clocksource is impossible and redundant in this case. + */ + if (!oops_in_progress) { + clocksource_change_rating(&hyperv_cs_tsc, 10); + clocksource_unregister(&hyperv_cs_tsc); + } hypercall_msr.as_uint64 = 0; wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
