On Mon, 17 Jun 2019, Florian Weimer wrote: > * Dave Martin: > > On Tue, Jun 11, 2019 at 12:31:34PM -0700, Yu-cheng Yu wrote: > >> We can probably check PT_GNU_PROPERTY first, and fallback (based on ld-linux > >> version?) to PT_NOTE scanning? > > > > For arm64, we can check for PT_GNU_PROPERTY and then give up > > unconditionally. > > > > For x86, we would fall back to PT_NOTE scanning, but this will add a bit > > of cost to binaries that don't have NT_GNU_PROPERTY_TYPE_0. The ld.so > > version doesn't tell you what ELF ABI a given executable conforms to. > > > > Since this sounds like it's largely a distro-specific issue, maybe there > > could be a Kconfig option to turn the fallback PT_NOTE scanning on? > > I'm worried that this causes interop issues similarly to what we see > with VSYSCALL today. If we need both and a way to disable it, it should > be something like a personality flag which can be configured for each > process tree separately. Ideally, we'd settle on one correct approach > (i.e., either always process both, or only process PT_GNU_PROPERTY) and > enforce that. Chose one and only the one which makes technically sense and is not some horrible vehicle. Everytime we did those 'oh we need to make x fly workarounds' we regretted it sooner than later. Thanks, tglx
