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![Krister Johansen](https://secure.gravatar.com/avatar/465c317763c3a21c303c14c0d90fba07.jpg?s=96&d=mm)
Krister Johansen committed 11a4d644d6d
perf callchain: Reference count maps commit aa33b9b9a2ebb00d33c83a5312d4fbf2d5aeba36 upstream. 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 <kjlx@templeofstupid.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Fixes: 84c2cafa2889 ("perf tools: Reference count struct map") Link: http://lkml.kernel.org/r/20170106062331.GB2707@templeofstupid.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>