From 7ed97ad41ffa94040dfd593948962a7e9e7b0db9 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Mon, 2 Jul 2012 09:12:57 -0600 Subject: [PATCH] perf kvm: Fix segfault with report and mixed guestmount use Using the guestmount option on record: $ perf kvm --guest --host --guestmount=/tmp/guest-mount record -ag But not the subsequent report: $ perf kvm report causes a SEGFAULT in the usual place: (gdb) bt 0 0x0000000000470356 in machine__mmap_name (self=0x0, bf=0x7fffffffbdb0 " z\370\367\377\177", size= 4096) at util/map.c:712 1 0x00000000004453e8 in perf_event__process_kernel_mmap (tool=0x7fffffffde10, event=0x7ffff7f87e38, machine=0x0) at util/event.c:550 2 0x00000000004458c9 in perf_event__process_mmap (tool=0x7fffffffde10, event=0x7ffff7f87e38, sample= 0x7fffffffd2a0, machine=0x0) at util/event.c:656 3 0x00000000004733e0 in perf_session_deliver_event (session=0x91aca0, event=0x7ffff7f87e38, sample= 0x7fffffffd2a0, tool=0x7fffffffde10, file_offset=7736) at util/session.c:979 ... The MMAP events in this case already contain the full path to the module. No need to require it for the report path to. Signed-off-by: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1341241977-71535-1-git-send-email-dsahern@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/map.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c index 35ae56864e4f..a1f4e3669142 100644 --- a/tools/perf/util/map.c +++ b/tools/perf/util/map.c @@ -669,25 +669,26 @@ struct machine *machines__find(struct rb_root *self, pid_t pid) struct machine *machines__findnew(struct rb_root *self, pid_t pid) { char path[PATH_MAX]; - const char *root_dir; + const char *root_dir = ""; struct machine *machine = machines__find(self, pid); - if (!machine || machine->pid != pid) { - if (pid == HOST_KERNEL_ID || pid == DEFAULT_GUEST_KERNEL_ID) - root_dir = ""; - else { - if (!symbol_conf.guestmount) - goto out; - sprintf(path, "%s/%d", symbol_conf.guestmount, pid); - if (access(path, R_OK)) { - pr_err("Can't access file %s\n", path); - goto out; - } - root_dir = path; + if (machine && (machine->pid == pid)) + goto out; + + if ((pid != HOST_KERNEL_ID) && + (pid != DEFAULT_GUEST_KERNEL_ID) && + (symbol_conf.guestmount)) { + sprintf(path, "%s/%d", symbol_conf.guestmount, pid); + if (access(path, R_OK)) { + pr_err("Can't access file %s\n", path); + machine = NULL; + goto out; } - machine = machines__add(self, pid, root_dir); + root_dir = path; } + machine = machines__add(self, pid, root_dir); + out: return machine; } -- GitLab