On Freitag, 18. März 2022 16:00:00 CET Mathieu Desnoyers wrote: > ----- On Mar 18, 2022, at 10:34 AM, lttng-dev lttng-dev@lists.lttng.org wrote: > > Hey all, > > > > in the past lttng-modules used to work on archlinux. But with a current > > kernel, I cannot get it to work anymore. Has anyone an idea what is going > > on here? > > > > I compiled and installed lttng-modules from the latest git, which works > > fine. > > > > ``` > > > > make > > sudo make modules_install > > sudo depmod -a > > > > ``` > > > > But loading the kernel modules then fails like this: > > > > ``` > > lttng-sessiond > > Error: Unable to load required module lttng-ring-buffer-client-discard > > Warning: No kernel tracer available > > ``` > > > > In dmesg I see the following output then, and I wonder if I'm doing > > something obviously wrong? > > > > ``` > > [16245.772646] Spectre V2 : System may be vulnerable to spectre v2 > > [16245.772653] lttng_uprobes: loading module not compiled with retpoline > > compiler. > > Hi Milian,
Hey Mathieu! > I suspect you need to use the same compiler (a compiler that supports > retpoline Spectre v2 mitigation) to compile lttng-modules as was used to > compile your kernel. > > I suspect the kernel rejects those modules because they are compiled with a > different compiler than your Linux kernel. Indeed, that seems to have been it. I wasn't deliberately using a different compiler (normal system GCC) but something seems to have influenced it. Using a clean environment without any of my normal overwrites has fixed the issue and now it works as expected. Thanks for making me try this once more! Cheers -- Milian Wolff | milian.wo...@kdab.com | Senior Software Engineer KDAB (Deutschland) GmbH, a KDAB Group company Tel: +49-30-521325470 KDAB - The Qt, C++ and OpenGL Experts
smime.p7s
Description: S/MIME cryptographic signature
_______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
