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3e9a18e1c3
ftrace_hash_ipmodify_enable() checks IPMODIFY and DIRECT ftrace_ops on the same kernel function. When needed, ftrace_hash_ipmodify_enable() calls ops->ops_func() to prepare the direct ftrace (BPF trampoline) to share the same function as the IPMODIFY ftrace (livepatch). ftrace_hash_ipmodify_enable() is called in register_ftrace_direct() path, but not called in modify_ftrace_direct() path. As a result, the following operations will break livepatch: 1. Load livepatch to a kernel function; 2. Attach fentry program to the kernel function; 3. Attach fexit program to the kernel function. After 3, the kernel function being used will not be the livepatched version, but the original version. Fix this by adding __ftrace_hash_update_ipmodify() to __modify_ftrace_direct() and adjust some logic around the call. Signed-off-by: Song Liu <song@kernel.org> Reviewed-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20251027175023.1521602-3-song@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>