3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dongsheng Yang <yangds.fnst@xxxxxxxxxxxxxx> commit ad85ace07a05062ef6b59c35a5e80b6eaee1eee6 upstream. Currently, if we use perf kvm --guestkallsyms --guestmodules report, we can not get the perf information from perf data file. All sample are shown as unknown. Reproducing steps: # perf kvm --guestkallsyms /tmp/kallsyms --guestmodules /tmp/modules record -a sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.624 MB perf.data.guest (~27260 samples) ] # perf kvm --guestkallsyms /tmp/kallsyms --guestmodules /tmp/modules report |grep % 100.00% [guest/6471] [unknown] [g] 0xffffffff8164f330 This bug was introduced by 207b57926 (perf kvm: Fix regression with guest machine creation). In original code, it uses perf_session__find_machine(), it means we deliver symbol to machine which has the same pid, if no machine found, deliver it to *default* guest. But if we use perf_session__findnew_machine() here, if no machine was found, new machine with pid will be built and added. Then the default guest which with pid == 0 will never get a symbol. And because the new machine initialized here has no kernel map created, the symbol delivered to it will be marked as "unknown". This patch here is to revert commit 207b57926 and fix the SEGFAULT bug in another way. Verification steps: # ./perf kvm --guestkallsyms /home/kallsyms --guestmodules /home/modules record -a sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.651 MB perf.data.guest (~28437 samples) ] # ./perf kvm --guestkallsyms /home/kallsyms --guestmodules /home/modules report |grep % 22.64% :6471 [guest.kernel.kallsyms] [g] update_rq_clock.part.70 19.99% :6471 [guest.kernel.kallsyms] [g] d_free 18.46% :6471 [guest.kernel.kallsyms] [g] bio_phys_segments 16.25% :6471 [guest.kernel.kallsyms] [g] dequeue_task 12.78% :6471 [guest.kernel.kallsyms] [g] __switch_to 7.91% :6471 [guest.kernel.kallsyms] [g] scheduler_tick 1.75% :6471 [guest.kernel.kallsyms] [g] native_apic_mem_write 0.21% :6471 [guest.kernel.kallsyms] [g] apic_timer_interrupt Signed-off-by: Dongsheng Yang <yangds.fnst@xxxxxxxxxxxxxx> Acked-by: David Ahern <dsahern@xxxxxxxxx> Cc: David Ahern <dsahern@xxxxxxxxx> Link: http://lkml.kernel.org/r/1387564907-3045-1-git-send-email-yangds.fnst@xxxxxxxxxxxxxx Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- tools/perf/util/session.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -811,6 +811,7 @@ static struct machine * union perf_event *event) { const u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK; + struct machine *machine; if (perf_guest && ((cpumode == PERF_RECORD_MISC_GUEST_KERNEL) || @@ -822,7 +823,11 @@ static struct machine * else pid = event->ip.pid; - return perf_session__findnew_machine(session, pid); + machine = perf_session__find_machine(session, pid); + if (!machine) + machine = perf_session__findnew_machine(session, + DEFAULT_GUEST_KERNEL_ID); + return machine; } return &session->machines.host; -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html