From: Arnaldo Carvalho de Melo <a...@redhat.com> Hook into the libtraceevent plugin kernel symbol resolver to warn the user that that can't happen with kptr_restrict=1.
Cc: Adrian Hunter <adrian.hun...@intel.com> Cc: David Ahern <dsah...@gmail.com> Cc: Jiri Olsa <jo...@kernel.org> Cc: Milian Wolff <milian.wo...@kdab.com> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Wang Nan <wangn...@huawei.com> Link: http://lkml.kernel.org/n/tip-9gc412xx1gl0lvqj1d1xw...@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/builtin-trace.c | 20 +++++++++++++++++++- tools/perf/util/machine.c | 1 + tools/perf/util/machine.h | 1 + 3 files changed, 21 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index 6e5c325148e4..e488ac756f39 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -1160,6 +1160,24 @@ static int trace__tool_process(struct perf_tool *tool, return trace__process_event(trace, machine, event, sample); } +static char *trace__machine__resolve_kernel_addr(void *vmachine, unsigned long long *addrp, char **modp) +{ + struct machine *machine = vmachine; + + if (machine->kptr_restrict_warned) + return NULL; + + if (symbol_conf.kptr_restrict) { + pr_warning("Kernel address maps (/proc/{kallsyms,modules}) are restricted.\n\n" + "Check /proc/sys/kernel/kptr_restrict.\n\n" + "Kernel samples will not be resolved.\n"); + machine->kptr_restrict_warned = true; + return NULL; + } + + return machine__resolve_kernel_addr(vmachine, addrp, modp); +} + static int trace__symbols_init(struct trace *trace, struct perf_evlist *evlist) { int err = symbol__init(NULL); @@ -1171,7 +1189,7 @@ static int trace__symbols_init(struct trace *trace, struct perf_evlist *evlist) if (trace->host == NULL) return -ENOMEM; - if (trace_event__register_resolver(trace->host, machine__resolve_kernel_addr) < 0) + if (trace_event__register_resolver(trace->host, trace__machine__resolve_kernel_addr) < 0) return -errno; err = __machine__synthesize_threads(trace->host, &trace->tool, &trace->opts.target, diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index b277984aaa93..bdc33ce40bdc 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -43,6 +43,7 @@ int machine__init(struct machine *machine, const char *root_dir, pid_t pid) machine->symbol_filter = NULL; machine->id_hdr_size = 0; + machine->kptr_restrict_warned = false; machine->comm_exec = false; machine->kernel_start = 0; diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h index 83f46790c52f..41ac9cfd416b 100644 --- a/tools/perf/util/machine.h +++ b/tools/perf/util/machine.h @@ -28,6 +28,7 @@ struct machine { pid_t pid; u16 id_hdr_size; bool comm_exec; + bool kptr_restrict_warned; char *root_dir; struct rb_root threads; pthread_rwlock_t threads_lock; -- 2.5.5
