Messages in this thread | | | From | Jisheng Zhang <> | Subject | Re: [PATCH v2 2/3] kprobes: adjust kprobe addr for KPROBES_ON_FTRACE | Date | Tue, 20 Aug 2019 10:41:15 +0000 |
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On Tue, 20 Aug 2019 15:45:24 +0530 "Naveen N. Rao" wrote:
> > > Jisheng Zhang wrote: > > For KPROBES_ON_FTRACE case, we need to adjust the kprobe's addr > > correspondingly. > > > > Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> > > --- > > kernel/kprobes.c | 10 +++++++--- > > 1 file changed, 7 insertions(+), 3 deletions(-) > > > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > > index 9873fc627d61..3fd2f68644da 100644 > > --- a/kernel/kprobes.c > > +++ b/kernel/kprobes.c > > @@ -1484,15 +1484,19 @@ static inline int check_kprobe_rereg(struct kprobe *p) > > > > int __weak arch_check_ftrace_location(struct kprobe *p) > > { > > - unsigned long ftrace_addr; > > + unsigned long ftrace_addr, addr = (unsigned long)p->addr; > > > > - ftrace_addr = ftrace_location((unsigned long)p->addr); > > +#ifdef CONFIG_KPROBES_ON_FTRACE > > + addr = ftrace_call_adjust(addr); > > +#endif > > Looking at the commit message for patch 3/3, it looks like you want the > probe to be placed on ftrace entry by default, and this patch seems to > be aimed at that.
Yeah.
> > If so, this is not the right approach. As I mentioned previously, you > would want to over-ride kprobe_lookup_name(). This ensures that the > address is changed only if the user provided a symbol, and not if the > user wanted to probe at a very specific address. See commit
Great! Now I understand the reason.
> 24bd909e94776 ("powerpc/kprobes: Prefer ftrace when probing function > entry").
Now, I got your meaning. You are right. I will update the patch in newer version.
Thanks a lot!
> > If this patch is for some other purpose, then it isn't clear from the > commit log. Please provide a better explanation. > > > - Naveen >
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