Re: [PATCH v5 3/3] selftests: livepatch: test livepatching a kprobed function

On Thu, 17 Oct 2024, Michael Vetter wrote:

The test proves that a function that is being kprobed and uses a post_handler cannot be livepatched.

Only one ftrace_ops with FTRACE_OPS_FL_IPMODIFY set may be registered to any given function at a time.

Note that the conflicting kprobe could not be created using the tracefs interface, see Documentation/trace/kprobetrace.rst. This interface uses only the pre_handler(), see alloc_trace_kprobe(). But FTRACE_OPS_FL_IPMODIFY is used only when the kprobe is using a post_handler, see arm_kprobe_ftrace().

Signed-off-by: Michael Vetter mvetter@suse.com

Nice test.

Reviewed-by: Miroslav Benes mbenes@suse.cz

Thank you, Miroslav