4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Krister Johansen <[email protected]> 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 <[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]> 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]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- tools/perf/util/callchain.c | 11 +++++++++-- tools/perf/util/callchain.h | 6 ++++++ tools/perf/util/hist.c | 7 +++++++ 3 files changed, 22 insertions(+), 2 deletions(-) --- a/tools/perf/util/callchain.c +++ b/tools/perf/util/callchain.c @@ -437,7 +437,7 @@ fill_node(struct callchain_node *node, s } call->ip = cursor_node->ip; call->ms.sym = cursor_node->sym; - call->ms.map = cursor_node->map; + call->ms.map = map__get(cursor_node->map); list_add_tail(&call->list, &node->val); callchain_cursor_advance(cursor); @@ -462,6 +462,7 @@ add_child(struct callchain_node *parent, list_for_each_entry_safe(call, tmp, &new->val, list) { list_del(&call->list); + map__zput(call->ms.map); free(call); } free(new); @@ -730,6 +731,7 @@ merge_chain_branch(struct callchain_curs callchain_cursor_append(cursor, list->ip, list->ms.map, list->ms.sym); list_del(&list->list); + map__zput(list->ms.map); free(list); } @@ -778,7 +780,8 @@ int callchain_cursor_append(struct callc } node->ip = ip; - node->map = map; + map__zput(node->map); + node->map = map__get(map); node->sym = sym; cursor->nr++; @@ -945,11 +948,13 @@ static void free_callchain_node(struct c list_for_each_entry_safe(list, tmp, &node->parent_val, list) { list_del(&list->list); + map__zput(list->ms.map); free(list); } list_for_each_entry_safe(list, tmp, &node->val, list) { list_del(&list->list); + map__zput(list->ms.map); free(list); } @@ -1013,6 +1018,7 @@ int callchain_node__make_parent_list(str goto out; *new = *chain; new->has_children = false; + map__get(new->ms.map); list_add_tail(&new->list, &head); } parent = parent->parent; @@ -1033,6 +1039,7 @@ int callchain_node__make_parent_list(str out: list_for_each_entry_safe(chain, new, &head, list) { list_del(&chain->list); + map__zput(chain->ms.map); free(chain); } return -ENOMEM; --- a/tools/perf/util/callchain.h +++ b/tools/perf/util/callchain.h @@ -5,6 +5,7 @@ #include <linux/list.h> #include <linux/rbtree.h> #include "event.h" +#include "map.h" #include "symbol.h" #define HELP_PAD "\t\t\t\t" @@ -174,8 +175,13 @@ int callchain_merge(struct callchain_cur */ static inline void callchain_cursor_reset(struct callchain_cursor *cursor) { + struct callchain_cursor_node *node; + cursor->nr = 0; cursor->last = &cursor->first; + + for (node = cursor->first; node != NULL; node = node->next) + map__zput(node->map); } int callchain_cursor_append(struct callchain_cursor *cursor, u64 ip, --- a/tools/perf/util/hist.c +++ b/tools/perf/util/hist.c @@ -1,6 +1,7 @@ #include "util.h" #include "build-id.h" #include "hist.h" +#include "map.h" #include "session.h" #include "sort.h" #include "evlist.h" @@ -1019,6 +1020,10 @@ int hist_entry_iter__add(struct hist_ent int max_stack_depth, void *arg) { int err, err2; + struct map *alm = NULL; + + if (al && al->map) + alm = map__get(al->map); err = sample__resolve_callchain(iter->sample, &callchain_cursor, &iter->parent, iter->evsel, al, max_stack_depth); @@ -1058,6 +1063,8 @@ out: if (!err) err = err2; + map__put(alm); + return err; }
