Re: [PATCH 5/6] nohz: support PR_DATAPLANE_STRICT mode
From: Peter Zijlstra <peterz@infradead.org>
Date: 2015-05-12 09:39:20
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On Fri, May 08, 2015 at 01:58:46PM -0400, Chris Metcalf wrote:
quoted hunk ↗ jump to hunk
+++ b/kernel/time/tick-sched.c@@ -436,6 +436,20 @@ static void dataplane_quiesce(void) (jiffies - start)); dump_stack(); } + + /* + * Kill the process if it violates STRICT mode. Note that this + * code also results in killing the task if a kernel bug causes an + * irq to be delivered to this core. + */ + if ((task->dataplane_flags & (PR_DATAPLANE_STRICT|PR_DATAPLANE_PRCTL)) + == PR_DATAPLANE_STRICT) { + pr_warn("Dataplane STRICT mode violated; process killed.\n"); + dump_stack(); + task->dataplane_flags &= ~PR_DATAPLANE_QUIESCE; + local_irq_enable(); + do_group_exit(SIGKILL); + } }
So while I'm all for hard fails like this, can we not provide a wee bit more information in the siginfo ? And maybe use a slightly less fatal signal, such that userspace can actually catch it and dump state in debug modes?