On Thu, 09 Oct 2014 13:00:59 +0000 Masami Hiramatsu <[email protected]> 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
