Re: [PATCH ftrace/core v3 2/3] ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict

[Steven Rostedt]

On Fri, 18 Jul 2014 16:09:07 +0900
Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx> wrote:


> > "The ops can modify the IP register. This can only be set along with
> > SAVE_REGS. If another ops is already registered for any of the
> > functions that this ops will be registered for, then this ops will fail
> > to register."
> 
> Not only register, but also set_filter_ip ;)
> "...will fail to register or set_filter_ip."

Sure.


> >> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> >> index 3214289..e52d86f 100644
> >> --- a/kernel/kprobes.c
> >> +++ b/kernel/kprobes.c
> > 
> > I think this should be split into two patches. One that adds the ftrace
> > infrastructure, and the other that adds the kprobes user of the
> > IPMODIFY flag.
> 
> Hmm, I thought that it was natural to introduce new feature and its user
> together, so that we could use git-bisect safely.

It should still be bisect friendly. That is, the feature is added
before the user, not the user before the feature ;-)

I know some people like the feature and user in one patch, but for me,
when the user is in a different sub system (here it's kprobes) from the
infrastructure that is changing (ftrace), I prefer separate patches.

The user patch shows me where the users are. When they are one patch, I
tend to have them get lost.

-- Steve
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