perf callchain: Reference count maps

If dso__load_kcore frees all of the existing maps, but one has already
been attached to a callchain cursor node, then we can get a SIGSEGV in
any function that happens to try to use this invalid cursor.  Use the
existing map refcount mechanism to forestall cleanup of a map until the
cursor iterates past the node.

Signed-off-by: Krister Johansen <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: [email protected]
Fixes: 84c2cafa2889 ("perf tools: Reference count struct map")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions