From 45e90056904b12d8dd74e0d2ea6dfd5e4394104d Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Tue, 17 May 2016 11:52:26 -0300 Subject: [PATCH] perf machine: Do not bail out if not managing to read ref reloc symbol This means the user can't access /proc/kallsyms, for instance, because /proc/sys/kernel/kptr_restrict is set to 1. Instead leave the ref_reloc_sym as NULL and code using it will cope. This allows 'perf trace' to work on such systems for !root, the only issue would be when trying to resolve kernel symbols, which happens, for instance, in some libtracevent plugins. A warning for that case will be provided in the next patch in this series. Noticed in Ubuntu 16.04, that comes with kptr_restrict=1. Reported-by: Milian Wolff Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-knpu3z4iyp2dxpdfm798fac4@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/machine.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 7ba9fadb68af..b277984aaa93 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -1135,10 +1135,10 @@ int machine__create_kernel_maps(struct machine *machine) { struct dso *kernel = machine__get_kernel(machine); const char *name; - u64 addr = machine__get_running_kernel_start(machine, &name); + u64 addr; int ret; - if (!addr || kernel == NULL) + if (kernel == NULL) return -1; ret = __machine__create_kernel_maps(machine, kernel); @@ -1160,8 +1160,9 @@ int machine__create_kernel_maps(struct machine *machine) */ map_groups__fixup_end(&machine->kmaps); - if (maps__set_kallsyms_ref_reloc_sym(machine->vmlinux_maps, name, - addr)) { + addr = machine__get_running_kernel_start(machine, &name); + if (!addr) { + } else if (maps__set_kallsyms_ref_reloc_sym(machine->vmlinux_maps, name, addr)) { machine__destroy_kernel_maps(machine); return -1; } -- 2.20.1