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From: "Qiu, PeiyangX" <peiyangx.qiu@intel.com>
To: Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@redhat.com>,
        Rusty Russell <rusty@rustcorp.com.au>
Cc: linux-kernel@vger.kernel.org, yanmin_zhang@linux.intel.com
Subject: [PATCH 0/2] fix ftrace initialization issue when a module is loaded
Message-ID: <567CE0A7.80605@intel.com>
Date: Fri, 25 Dec 2015 14:22:31 +0800
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When a module is loaded, current ftrace initialization around the new module
has some issues.

1) ftrace might race with insmod: Just after load_module calls
ftrace_module_init to add ftrace records of the module, ftrace_run_update_code
might jump in to change module codes. But load_module calls
complete_formation=>set_section_ro_nx to put the module TEXT attribute to RO.
Then, ftrace_run_update_code triggers ftrace_bug and fails.

2) complete_formation might fail and the module's ftrace records are not
cleaned up.

This patchset fixes above issues.