Reference to non-existing DYNAMIC_FTRACE_WITH_ARGS

Hi Steven,

Commit 2860cd8a2353 ("livepatch: Use the default ftrace_ops instead of
REGS when ARGS is available") adds a dependency on a non-existing
config DYNAMIC_FTRACE_WITH_ARGS, see diff:

diff --git a/kernel/livepatch/Kconfig b/kernel/livepatch/Kconfig
index 54102deb50ba..53d51ed619a3 100644
--- a/kernel/livepatch/Kconfig
+++ b/kernel/livepatch/Kconfig

@@ -6,7 +6,7 @@ config HAVE_LIVEPATCH

 config LIVEPATCH
        bool "Kernel Live Patching"
-       depends on DYNAMIC_FTRACE_WITH_REGS
+       depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS
        depends on MODULES
        depends on SYSFS
        depends on KALLSYMS_ALL

Did you intend to depend on the existing "HAVE_DYNAMIC_FTRACE_WITH_ARGS" here?

Or did you intend to add a new config DYNAMIC_FTRACE_WITH_ARGS
analogously to DYNAMIC_FTRACE_WITH_REGS as defined in
./kernel/trace/Kconfig (see below)?

config DYNAMIC_FTRACE_WITH_REGS
        def_bool y
        depends on DYNAMIC_FTRACE
        depends on HAVE_DYNAMIC_FTRACE_WITH_REGS

I am happy to provide a patch, once I understand what was intended here.

Lukas

On Fri, 6 Aug 2021 12:18:36 +0200
Lukas Bulwahn [off-list ref] wrote:

Hi Steven,

Hi Lukas, thanks for the report.

Did you intend to depend on the existing "HAVE_DYNAMIC_FTRACE_WITH_ARGS" here?

Or did you intend to add a new config DYNAMIC_FTRACE_WITH_ARGS
analogously to DYNAMIC_FTRACE_WITH_REGS as defined in
./kernel/trace/Kconfig (see below)?

config DYNAMIC_FTRACE_WITH_REGS
        def_bool y
        depends on DYNAMIC_FTRACE
        depends on HAVE_DYNAMIC_FTRACE_WITH_REGS

I am happy to provide a patch, once I understand what was intended here.

Yeah, that looks to be the missing part. The
HAVE_DYNAMIC_FTRACE_WITH_ARGS is just showing support, but knowing it
is enabled would require DYNAMIC_FTRACE being set (which is user
enabled).

Feel free to send a patch, and mark it for stable.

-- Steve