perf callchain: Reference count maps
authorKrister Johansen <kjlx@templeofstupid.com>
Fri, 6 Jan 2017 06:23:31 +0000 (22:23 -0800)
committerArnaldo Carvalho de Melo <acme@redhat.com>
Tue, 31 Jan 2017 19:19:06 +0000 (16:19 -0300)
commit9c68ae98c6f714ef573826cfc9055af1bd5e97b1
treef87b3cf4812f70534c8cc2309c934d6ffab69bbc
parentc0621acf45a9d8c3b501633b5eca11495fff8f66
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 <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>
Cc: stable@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>
tools/perf/util/callchain.c
tools/perf/util/callchain.h
tools/perf/util/hist.c