There are cases where looking at just the next and prev entries is not
enough, like with:

  $ readelf -sW /usr/lib/debug/lib/modules/4.3.3-301.fc23.x86_64/vmlinux | grep ffffffff81065ec0
   4979: ffffffff81065ec0 53 FUNC  LOCAL  DEFAULT 1 try_to_free_pud_page
   4980: ffffffff81065ec0 53 FUNC  LOCAL  DEFAULT 1 try_to_free_pte_page
   4981: ffffffff81065ec0 53 FUNC  LOCAL  DEFAULT 1 try_to_free_pmd_page

So just search by name to see if the symbol is in kallsyms.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-jj1vlljg7ol4i713l60rt5ai@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>