Messages in this thread | | | Date | Tue, 13 Dec 2022 11:36:05 +0000 | From | Will Deacon <> | Subject | Re: [PATCH] ftrace: Allow WITH_ARGS flavour of graph tracer with shadow call stack |
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On Mon, Dec 12, 2022 at 10:36:23AM +0000, Mark Rutland wrote: > On Fri, Dec 09, 2022 at 04:51:39PM -0500, Steven Rostedt wrote: > > On Fri, 9 Dec 2022 14:40:25 +0000 > > Mark Rutland <mark.rutland@arm.com> wrote: > > > > > On Fri, Dec 09, 2022 at 03:34:02PM +0100, Ard Biesheuvel wrote: > > > > The recent switch on arm64 from DYNAMIC_FTRACE_WITH_REGS to > > > > DYNAMIC_FTRACE_WITH_ARGS failed to take into account that we currently > > > > require the former in order to allow the function graph tracer to be > > > > enabled in combination with shadow call stacks. This means that this is > > > > no longer permitted at all, in spite of the fact that either flavour of > > > > ftrace works perfectly fine in this combination. > > > > > > > > Given that arm64 is the only arch that implements shadow call stacks in > > > > the first place, let's update the condition to just reflect the arm64 > > > > change. When other architectures adopt shadow call stack support, this > > > > can be revisited if needed. > > > > > > > > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> > > > > > > My bad; sorry about this, and thanks for the fix! > > > > > > Acked-by: Mark Rutland <mark.rutland@arm.com> > > > > > > We should probably also add: > > > > > > Fixes: 26299b3f6ba26bfc ("ftrace: arm64: move from REGS to ARGS") > > > > Actually, I believe it is: > > > > Fixes: ddc9863e9e90 ("scs: Disable when function graph tracing is enabled") > > Ah; it's slightly more subtle since these were on different branches that got > merged. Either's correct in its own branch, and the merge is where things went > wrong. > > I think the overall least confusing thing is to bite the bullet and list both > REGS and ARGS, i.e. > > depends on DYNAMIC_FTRACE_WITH_ARGS || DYNAMIC_FTRACE_WITH_REGS || !FUNCTION_GRAPH_TRACER > > ... and for the fixes tag have: > > Fixes: ddc9863e9e90 ("scs: Disable when function graph tracing is enabled") > > That way the commit is correct regardless of the REGS -> ARGS conversion, and > will work if backported independently.
Ard -- please can you respin as per Mark's suggestion above? I can then send it as a fix later this week.
Cheers,
Will
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