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perf trace: Warn when trying to resolve kernel addresses with kptr_restrict=1

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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.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-9gc412xx1gl0lvqj1d1xwlyb@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2016-05-17 11:56:24 -03:00
parent 45e9005690
commit caf8a0d049
3 changed files with 21 additions and 1 deletions
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20
tools/perf/builtin-trace.c
View File

@ -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,

1
tools/perf/util/machine.c
View File

@ -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;

1
tools/perf/util/machine.h
View File

@ -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;