On 04/19/2017 07:33 PM, Steven Rostedt wrote:

On Wed, 19 Apr 2017 16:27:10 -0700
Tyrel Datwyler [off-list ref] wrote:

quoted

# echo stacktrace > /sys/kernel/debug/tracing/trace_options
# cat trace | grep -A6 "/pci@800000020000018"

Just to let you know that there is now stacktrace event triggers, where
you don't need to stacktrace all events, you can pick and choose. And
even filter the stack trace on specific fields of the event.

This is great, and I did figure that out this afternoon. One thing I was
still trying to determine though was whether its possible to set these
triggers at boot? As far as I could tell I'm still limited to
"trace_options=stacktrace" as a kernel boot parameter to get the stack
for event tracepoints.

-Tyrel

 # cd /sys/kernel/debug/tracing
 # echo "stacktrace if common_pid == $$ && reason == 3" \
   > events/tlb/tlb_flush/trigger

 # cat trace
            bash-1103  [003] ...1  1290.100133: tlb_flush: pages:-1 reason:local mm shootdown (3)
            bash-1103  [003] ...2  1290.100140: <stack trace>
 => copy_process.part.39
 => _do_fork
 => SyS_clone
 => do_syscall_64
 => return_from_SYSCALL_64

-- Steve