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authorMasami Hiramatsu <mhiramat@kernel.org>2020-10-15 23:55:25 +0900
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2021-02-11 16:31:57 -0500
commita345a6718bd5689f7cff7715e902d8739e0d5beb (patch)
tree5924d99849bd3cc4fc2072f69a46f377114cc807 /Documentation/trace
parent1600cbcf6944dee9f87f52cbceb0b6895c29efd0 (diff)
tracing: Add ptr-hash option to show the hashed pointer value
Add tracefs/options/hash-ptr option to show hashed pointer value by %p in event printk format string. For the security reason, normal printk will show the hashed pointer value (encrypted by random number) with %p to printk buffer to hide the real address. But the tracefs/trace always shows real address for debug. To bridge those outputs, add an option to switch the output format. Ftrace users can use it to find the hashed value corresponding to the real address in trace log. Link: https://lkml.kernel.org/r/160277372504.29307.14909828808982012211.stgit@devnote2 Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'Documentation/trace')
-rw-r--r--Documentation/trace/ftrace.rst6
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst
index 87cf5c010d5d..62c98e9bbdd9 100644
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -1159,6 +1159,12 @@ Here are the available options:
This simulates the original behavior of the trace file.
When the file is closed, tracing will be enabled again.
+ hash-ptr
+ When set, "%p" in the event printk format displays the
+ hashed pointer value instead of real address.
+ This will be useful if you want to find out which hashed
+ value is corresponding to the real value in trace log.
+
record-cmd
When any event or tracer is enabled, a hook is enabled
in the sched_switch trace point to fill comm cache