Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [PATCH v4 1/6] timer: kasan: record timer stack | Date | Thu, 24 Sep 2020 23:41:27 +0200 |
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On Thu, Sep 24 2020 at 12:03, Walter Wu wrote: > When analyze use-after-free or double-free issue, recording the timer > stacks is helpful to preserve usage history which potentially gives > a hint about the affected code. > > Record the most recent two timer init calls in KASAN which are printed > on failure in the KASAN report. > > For timers it has turned out to be useful to record the stack trace > of the timer init call.
In which way? And what kind of bug does it catch which cannot be catched by existing debug mechanisms already?
> Because if the UAF root cause is in timer init, then user can see > KASAN report to get where it is registered and find out the root > cause.
What? If the UAF root cause is in timer init, then registering it after using it in that very same function is pretty pointless.
> It don't need to enable DEBUG_OBJECTS_TIMERS, but they have a chance > to find out the root cause.
There is a lot of handwaving how useful this is, but TBH I don't see the value at all.
DEBUG_OBJECTS_TIMERS does a lot more than crashing on UAF. If KASAN provides additional value over DEBUG_OBJECTS_TIMERS then spell it out, but just saying that you don't need to enable DEBUG_OBJECTS_TIMERS is not making an argument for that change.
Try again please.
Thanks,
tglx
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