Messages in this thread |  | | Subject | Re: [RFC 0/5] kernel: backtrace unwind support | From | Benjamin Herrenschmidt <> | Date | Tue, 14 Feb 2012 13:22:24 +1100 |
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On Fri, 2012-02-10 at 12:37 -0800, Linus Torvalds wrote: > On Fri, Feb 10, 2012 at 12:18 PM, Jiri Olsa <jolsa@redhat.com> wrote: > > > > yep, looks interesting.. not sure about the mathematical proof though ;) > > Well, I can already say what the old code did horribly horribly wrong: > > - *all* stack accesses need to go through a validation function, they > can never *ever* just try to access the stack. > > The validation function really needs to really check the full > range of the stack area, not something random. > > - all dwarf information accesses need to similarly validate the > access, and accept that sometimes the dwarf info is simply missing or > actively wrong.
In addition it should all go through something like copy_from_user_inatomic(), ie, all access to that stuff should have built-in fault recovery without triggering high level page faults, stack expansion etc...
Cheers, Ben.
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