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    SubjectRe: [PATCH v2 12/39] x86/ibt,ftrace: Search for __fentry__ location
    On Fri, 25 Feb 2022 00:55:20 +0900
    Masami Hiramatsu <mhiramat@kernel.org> wrote:

    > > unsigned long ftrace_location(unsigned long ip)
    > > {
    > > - return ftrace_location_range(ip, ip);
    > > + struct dyn_ftrace *rec;
    > > + unsigned long offset;
    > > + unsigned long size;
    > > +
    > > + rec = lookup_rec(ip, ip);
    > > + if (!rec) {
    > > + if (!kallsyms_lookup_size_offset(ip, &size, &offset))
    > > + goto out;
    > > +
    > > + if (!offset)
    >
    > Isn't this 'if (offset)' ?

    No, the point to only look for the fentry location if the ip passed in
    points to the start of the function. IOW, +0 offset.

    -- Steve


    >
    > > + rec = lookup_rec(ip - offset, (ip - offset) + size);
    > > + }
    > > +
    > > + if (rec)
    > > + return rec->ip;
    > > +
    > > +out:
    > > + return 0;

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