Messages in this thread | | | Date | Fri, 5 Apr 2019 10:12:27 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: WARN_ON: userstacktrace on irq events |
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On Wed, 3 Apr 2019, Steven Rostedt wrote: > Juri reported this from the -rt kernel, but I can easily trigger it in > mainline. By simply doing: > > # cd /sys/kernel/tracing > # echo 1 > options/userstacktrace > # echo 1 > events/irq/enable > This is simply caused by the irq trace events doing a user stack trace: > > ftrace_trace_userstack { > save_stack_trace_user { > __save_stack_trace_user { > copy_stack_frame { > access_ok { > WARN_ON_IN_IRQ() > > BOOM! Warn on. > > Can we make that access_ok() call in the copy_stack_frame not trigger > the warning just if we are in an interrupt?
You really want to have access_ok_atomic() or such which does not have the WARN and use that in copy_stack_frame(). That's fine here because the actual copy is inside a pagefault disabled region.
Thanks,
tglx
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