The following commit has been merged into the sched/core branch of tip: Commit-ID: 02d4ac5885a18d326b500b94808f0956dcce2832 Gitweb: https://git.kernel.org/tip/02d4ac5885a18d326b500b94808f0956dcce2832 Author: Wei Li <liwei391@xxxxxxxxxx> AuthorDate: Thu, 26 Dec 2019 16:52:24 +08:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Fri, 17 Jan 2020 10:19:20 +01:00 sched/debug: Reset watchdog on all CPUs while processing sysrq-t Lengthy output of sysrq-t may take a lot of time on slow serial console with lots of processes and CPUs. So we need to reset NMI-watchdog to avoid spurious lockup messages, and we also reset softlockup watchdogs on all other CPUs since another CPU might be blocked waiting for us to process an IPI or stop_machine. Add to sysrq_sched_debug_show() as what we did in show_state_filter(). Signed-off-by: Wei Li <liwei391@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Reviewed-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Link: https://lkml.kernel.org/r/20191226085224.48942-1-liwei391@xxxxxxxxxx --- kernel/sched/debug.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index f7e4579..879d3cc 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -751,9 +751,16 @@ void sysrq_sched_debug_show(void) int cpu; sched_debug_header(NULL); - for_each_online_cpu(cpu) + for_each_online_cpu(cpu) { + /* + * Need to reset softlockup watchdogs on all CPUs, because + * another CPU might be blocked waiting for us to process + * an IPI or stop_machine. + */ + touch_nmi_watchdog(); + touch_all_softlockup_watchdogs(); print_cpu(NULL, cpu); - + } } /*