Messages in this thread | | | Date | Wed, 14 Jan 2015 00:34:13 +0900 | From | Masami Hiramatsu <> | Subject | Re: [RFC PATCH 01/11] ARM: kprobes: directly modify code if kprobe is not initialized. |
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(2015/01/07 16:35), Wang Nan wrote: > If kprobe is optimized before kprobe is initialized, there should > be only one core, the probed instruction is not armed with breakpoint, > so simply patch text is okay.
This patch looks very hacky. If kprobes is not initialized, why anyone can optimize kprobes? I think you must introduce early kprobes init routine and set init flag at that point.
Thank you,
> > Signed-off-by: Wang Nan <wangnan0@huawei.com> > --- > arch/arm/probes/kprobes/opt-arm.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/probes/kprobes/opt-arm.c b/arch/arm/probes/kprobes/opt-arm.c > index 15b37c0..a021474 100644 > --- a/arch/arm/probes/kprobes/opt-arm.c > +++ b/arch/arm/probes/kprobes/opt-arm.c > @@ -325,8 +325,17 @@ void __kprobes arch_optimize_kprobes(struct list_head *oplist) > * Similar to __arch_disarm_kprobe, operations which > * removing breakpoints must be wrapped by stop_machine > * to avoid racing. > + * > + * If this function is called before kprobes initialized, > + * the kprobe should be an early kprobe, the instruction > + * is not armed with breakpoint. There should be only > + * one core now, so directly __patch_text is enough. > */ > - kprobes_remove_breakpoint(op->kp.addr, insn); > + if (unlikely(!kprobes_initialized)) { > + BUG_ON(!(op->kp.flags & KPROBE_FLAG_EARLY)); > + __patch_text(op->kp.addr, insn); > + } else > + kprobes_remove_breakpoint(op->kp.addr, insn); > > list_del_init(&op->list); > } >
-- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Research Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com
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