ftrace: Keep the resolved addr in kallsyms_callback
authorJiri Olsa <jolsa@kernel.org>
Mon, 26 Sep 2022 15:33:36 +0000 (17:33 +0200)
committerAlexei Starovoitov <ast@kernel.org>
Tue, 27 Sep 2022 03:30:39 +0000 (20:30 -0700)
commit9d68c19c57d690547cde977bb3d9ccd3ceb6afe9
tree0a906475e49c0367b5ed85d45eb1b27d6ef97f08
parentbf7a87f1075f67c286f794519f0fedfa8b0b18cc
ftrace: Keep the resolved addr in kallsyms_callback

Keeping the resolved 'addr' in kallsyms_callback, instead of taking
ftrace_location value, because we depend on symbol address in the
cookie related code.

With CONFIG_X86_KERNEL_IBT option the ftrace_location value differs
from symbol address, which screwes the symbol address cookies matching.

There are 2 users of this function:
- bpf_kprobe_multi_link_attach
    for which this fix is for

- get_ftrace_locations
    which is used by register_fprobe_syms

    this function needs to get symbols resolved to addresses,
    but does not need 'ftrace location addresses' at this point
    there's another ftrace location translation in the path done
    by ftrace_set_filter_ips call:

     register_fprobe_syms
       addrs = get_ftrace_locations

       register_fprobe_ips(addrs)
         ...
         ftrace_set_filter_ips
           ...
             __ftrace_match_addr
               ip = ftrace_location(ip);
               ...

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220926153340.1621984-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
kernel/trace/ftrace.c