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ftrace: Ensure /proc/kallsyms contains symbol addresses

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The content of /proc/kallsyms depends on the value of
/proc/sys/kernel/kptr_restrict:
* If 0, restriction is lifted and kallsyms contains real addresses
* If 1, kallsyms will contain null pointers

Since trace-cmd records the content of kallsyms into the trace.dat and uses that
to pretty-print function names (function tracer/grapher), ensure that its
content is available.

Signed-off-by: Douglas RAILLARD <douglas.raillard@arm.com>
This commit is contained in:
Douglas RAILLARD 2019-11-04 17:47:06 +00:00 committed by Marc Bonnici
parent 2650a534f3
commit 0e6280ae31
1 changed files with 6 additions and 0 deletions
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6
devlib/trace/ftrace.py
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@ -20,6 +20,7 @@ import time
import re import re
import subprocess import subprocess
import sys import sys
import contextlib
from pipes import quote from pipes import quote
from devlib.trace import TraceCollector from devlib.trace import TraceCollector
@ -226,6 +227,11 @@ class FtraceCollector(TraceCollector):
tracer_string = '-p {}'.format(self.tracer) if self.tracer else '' tracer_string = '-p {}'.format(self.tracer) if self.tracer else ''
# Ensure kallsyms contains addresses if possible, so that function the
# collected trace contains enough data for pretty printing
with contextlib.suppress(TargetStableError):
self.target.write_value('/proc/sys/kernel/kptr_restrict', 0)
self.target.write_value(self.trace_clock_file, self.trace_clock, verify=False) self.target.write_value(self.trace_clock_file, self.trace_clock, verify=False)
try: try:
self.target.write_value(self.save_cmdlines_size_file, self.saved_cmdlines_nr) self.target.write_value(self.save_cmdlines_size_file, self.saved_cmdlines_nr)