Hi Alan and Zong, I initially suspected ftrace is broken between v5.6 & v5.7 as Kolin pointed out. I couldn't find any reason how the HSM patch is related. Zong's ftrace patching code was also merged in that release. However, I was able to reproduce the issue in the older kernel(v5.4) as well on both Qemu & Unleashed hardware. Here are the steps:
mount -t debugfs none /sys/kernel/debug/ cd /sys/kernel/debug/tracing echo function_graph > current_tracer echo function > current_tracer It works for the first time with function_graph but writing any other tracer crashes immediately. Can you take a look to check if the bug is in ftrace infrastructure code ? On Mon, Sep 28, 2020 at 10:25 AM Atish Patra <atish.pa...@wdc.com> wrote: > > On Mon, 2020-09-28 at 11:13 -0400, Steven Rostedt wrote: > > On Sat, 26 Sep 2020 22:02:35 +0000 > > bugzilla-dae...@bugzilla.kernel.org wrote: > > > > > https://bugzilla.kernel.org/show_bug.cgi?id=209317 > > > > > > --- Comment #4 from Colin Ian King (colin.k...@canonical.com) --- > > > Issue still in 5.9-rc6 > > > > > > > Atish, > > > > As the issues bisects down to your commit, care to take a look at > > this. > > (And take ownership of this bug) > > > > Yes. I am already looking into this. Colin informed me about the bug > over the weekend. > > I couldn't change the ownership as I am not part of the editbugs group. > I have sent an email to helpd...@kernel.org for access. > > > -- Steve > > -- > Regards, > Atish > _______________________________________________ > linux-riscv mailing list > linux-ri...@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv -- Regards, Atish