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author | Steven Rostedt <srostedt@redhat.com> | 2009-02-13 20:53:42 -0500 |
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committer | Steven Rostedt <srostedt@redhat.com> | 2009-02-16 17:03:49 -0500 |
commit | e68746a271eb3393a2183840be9e903caddf765b (patch) | |
tree | 106ea87792837ccee1476687d9f9a067f96488a9 /Documentation/RCU/RTFP.txt | |
parent | 64e7c440618998fd69eee6ab490b042d12248021 (diff) |
ftrace: enable filtering only when a function is filtered on
Impact: fix to prevent empty set_ftrace_filter and no ftrace output
The function filter is used to only trace a given set of functions.
The filter is enabled when a function name is echoed into the
set_ftrace_filter file. But if the name has a typo and the function
is not found, the filter is enabled, but no function is listed.
This makes a confusing situation where set_ftrace_filter is empty
but no functions ever get enabled for tracing.
For example:
# cat /debug/tracing/set_ftrace_filter
#### all functions enabled ####
# echo bad_name > set_ftrace_filter
# cat /debug/tracing/set_ftrace_filter
# echo function > current_tracer
# cat trace
# tracer: nop
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
This patch changes that to only enable filtering if a function
is set to be filtered on. Now, the filter is not enabled if
a bad name is echoed into set_ftrace_filter.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Diffstat (limited to 'Documentation/RCU/RTFP.txt')
0 files changed, 0 insertions, 0 deletions