On Fri, 13 Sep 2024 08:03:51 +0200 Sven Schnelle <svens@xxxxxxxxxxxxx> wrote: > Sven Schnelle <svens@xxxxxxxxxxxxx> writes: > > > Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> writes: > > > >> On Fri, 6 Sep 2024 10:07:38 -0400 > >> Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > >> > >>> On Fri, 06 Sep 2024 08:18:02 +0200 > >>> Sven Schnelle <svens@xxxxxxxxxxxxx> wrote: > >>> > >>> > >>> > One thing i learned after submitting the series is that struct > >>> > ftrace_regs depends on CONFIG_FUNCTION_TRACER, so it cannot be used > >>> > with the graph tracer. > >> > >> Yeah, this is solved by my series [1]. > >> > >> [1] https://patchwork.kernel.org/project/linux-trace-kernel/patch/172398532480.293426.13232399076477198126.stgit@devnote2/ > >> > >> So I think this series is easier to apply after my series, which > >> passes fgraph_regs in return handler. > > > > Thanks, i'll rebase my changes on top of your patches then. > > While doing so i noticed that i completely forgot about arguments > located on the stack. The current patchset tries to read from the > current kernel stack, which is obviously wrong. So either the tracer > needs to save the stack frame in the ringbuffer (which would be quite > a lot of data), or ftrace only prints arguments located in registers. > Also not nice. Opinions? We can limit it to first 6 arguments in the ftrace_regs by default, no need to save all of them. We can add an option to specify how many stack entries (but it is set 0 by default). Thank you, > > Thanks > Sven -- Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
