Messages in this thread | | | Subject | Re: [PATCH 4/5] sh: ftrace: fix the comments for ftrace_modify_code | From | Sergei Shtylyov <> | Date | Fri, 4 Dec 2015 15:44:27 +0300 |
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Hello.
On 12/4/2015 10:27 AM, Li Bin wrote:
> There is no need to worry about module and __init text disappearing > case, because that ftrace has a module notifier that is called when > a module is being unloaded and before the text goes away and this > code grabs the ftrace_lock mutex and removes the module functions > from the ftrace list, such that it will no longer do any > modifications to that module's text, the update to make functions > be traced or not is done under the ftrace_lock mutex as well. > And by now, __init section codes should not been modified > by ftrace, because it is black listed in recordmcount.c and > ignored by ftrace. > > Cc: linux-sh@vger.kernel.org > Suggested-by: Steven Rostedt <rostedt@goodmis.org> > Signed-off-by: Li Bin <huawei.libin@huawei.com> > --- > arch/sh/kernel/ftrace.c | 13 ++++++------- > 1 files changed, 6 insertions(+), 7 deletions(-) > > diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c > index 079d70e..b696f92 100644 > --- a/arch/sh/kernel/ftrace.c > +++ b/arch/sh/kernel/ftrace.c > @@ -212,13 +212,12 @@ static int ftrace_modify_code(unsigned long ip, unsigned char *old_code, > unsigned char replaced[MCOUNT_INSN_SIZE]; > > /* > - * Note: Due to modules and __init, code can > - * disappear and change, we need to protect against faulting > - * as well as code changing. We do this by using the > - * probe_kernel_* functions. > - * > - * No real locking needed, this code is run through > - * kstop_machine, or before SMP starts. > + * Note: > + * We are paranoid about modifying text, as if a bug were to happen, it
s/were/was/.
[...]
MBR, Sergei
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