Messages in this thread | | | From | Joel Fernandes <> | Date | Tue, 30 Jul 2019 00:19:36 -0400 | Subject | Re: [PATCH] tracing: Prevent RCU EQS breakage in preemptirq events |
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On Mon, Jul 29, 2019 at 10:15 PM Steven Rostedt <rostedt@goodmis.org> wrote: [snip] > > If the problem was only with userstacktrace, it will be reasonable to > > surround only the userstack unwinder. But the situation is similar to > > the previous "tracing vs CR2" case. As Peter taught me in > > https://lore.kernel.org/lkml/20190708074823.GV3402@hirez.programming.kicks-ass.net/ > > there are some other codes likely to to user access. > > So I surround preemptirq events earlier. > > I disagree. The issue is with the attached callbacks that call > something (a stack unwinder) that can fault. > > This is called whenever irqs are disabled. I say we surround the > culprit (the stack unwinder or stack trace) and not punish the irq > enable/disable events.
I agree with everything Steve said.
thanks,
- Joel
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