tree 238860c1dbc3a58e034dde0c7b299a3773347660
parent 8252ecf346474cfe46315bd0a7ca655c293c34a9
author Steven Rostedt (Red Hat) <rostedt@goodmis.org> 1414176515 -0400
committer Steven Rostedt <rostedt@goodmis.org> 1414183991 -0400

ftrace: Fix checking of trampoline ftrace_ops in finding trampoline

When modifying code, ftrace has several checks to make sure things
are being done correctly. One of them is to make sure any code it
modifies is exactly what it expects it to be before it modifies it.
In order to do so with the new trampoline logic, it must be able
to find out what trampoline a function is hooked to in order to
see if the code that hooks to it is what's expected.

The logic to find the trampoline from a record (accounting descriptor
for a function that is hooked) needs to only look at the "old_hash"
of an ops that is being modified. The old_hash is the list of function
an ops is hooked to before its update. Since a record would only be
pointing to an ops that is being modified if it was already hooked
before.

Currently, it can pick a modified ops based on its new functions it
will be hooked to, and this picks the wrong trampoline and causes
the check to fail, disabling ftrace.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

ftrace: squash into ordering of ops for modification