Messages in this thread | | | Date | Thu, 9 Oct 2014 11:21:57 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH ftrace/for-next v5 0/5] ftrace, kprobes: Introduce IPMODIFY flag for ftrace_ops to detect conflicts |
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On Thu, 09 Oct 2014 13:00:59 +0000 Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote:
> Hi, > > Here is the 5th version of the series of patches which introduces > IPMODIFY flag for ftrace_ops to detect conflicts of ftrace users > who can modify regs->ip in their handler. > > The previous version is here; > https://lkml.org/lkml/2014/7/28/13 > > This version is basically an update of previous version to the > latest ftrace tree, and adding a test code to selftest. > > Currently, only kprobes can change the regs->ip in the handler, > but recently kpatch is also want to change it. Moreover, since > the ftrace itself exported to modules, it might be considerable > senario. > > Here we talked on github. > https://github.com/dynup/kpatch/issues/47 > > To protect modified regs-ip from each other, this series > introduces FTRACE_OPS_FL_IPMODIFY flag and ftrace now ensures > the flag can be set on each function entry location. If there > is someone who already reserve regs->ip on target function > entry, ftrace_set_filter_ip or register_ftrace_function will > return -EBUSY. Users must handle that. > The ftrace_ops with IPMODIFY flag requires at least one > entry for filter hash, and its notrace_hash must be empty, > because the IPMODIFY action is very address sensitve and > user must consider the ip address. > > The 3rd patch adds a special reservation of IPMODIFY on the > jprobed address, since it is the only user who will change > the regs->ip. Other kprobes do not change it anymore. > > Thank you, >
Masami,
Thanks for sending this. I'm going to look at it after Dusseldorf. It's too late to get it into 3.18, but it looks like a good fit for the work I have for 3.19.
Just don't let me forget you sent this :-) Even though I tagged it as important, I'm sure I'll be tagging a lot of other emails as important in the next week.
Also, my main test box has finally died. I ordered a new motherboard (thanks Linus for the suggestion!) and unfortunately it is due to arrive tomorrow. That's the same day I leave and I don't trust my wife to install it for me ;-)
This means I can not do my tests that I like to run before adding to linux-next.
-- Steve
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