Messages in this thread | | | Subject | Re: [PATCH v2 3/5] x86/mm: check exec permissions on fault | From | Nadav Amit <> | Date | Mon, 25 Oct 2021 10:51:21 -0700 |
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> On Oct 25, 2021, at 10:45 AM, Dave Hansen <dave.hansen@intel.com> wrote: > > On 10/25/21 9:19 AM, Nadav Amit wrote: >> That was my first version, but I was concerned that perhaps there is >> some strange scenario in which both X86_PF_WRITE and X86_PF_INSN can >> be set. That is the reason that Peter asked you whether this is >> something that might happen. >> >> If you confirm they cannot be both set, I would the version you just >> mentioned. > > I'm pretty sure they can't be set together on any sane hardware. A > bonkers hypervisor or CPU could do it of course, but they'd be crazy. > > BTW, feel free to add a WARN_ON_ONCE() if WRITE and INSN are both set. > That would be a nice place to talk about the assumption. >
I can do that. But be aware that if the assumption is broken, it might lead to the application getting stuck in an infinite loop of page-faults instead of receiving SIGSEGV.
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