diff --git a/tools/perf/tests/dwarf-unwind.c b/tools/perf/tests/dwarf-unwind.c
index 2dab2d2620608b5b5bf458d76144aa72253321d5..afdca7f2959f07d87716c26508178bb6647bd9cf 100644
--- a/tools/perf/tests/dwarf-unwind.c
+++ b/tools/perf/tests/dwarf-unwind.c
@@ -122,7 +122,7 @@ NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__thread(struct thread *thr
}
err = unwind__get_entries(unwind_entry, &cnt, thread,
- &sample, MAX_STACK);
+ &sample, MAX_STACK, false);
if (err)
pr_debug("unwind failed\n");
else if (cnt != MAX_STACK) {
diff --git a/tools/perf/util/arm64-frame-pointer-unwind-support.c b/tools/perf/util/arm64-frame-pointer-unwind-support.c
index 2242a885fbd73387ffd347deba3bceb4ac74a95a..4940be4a0569cd441cee2c265433a2a06181c8fa 100644
--- a/tools/perf/util/arm64-frame-pointer-unwind-support.c
+++ b/tools/perf/util/arm64-frame-pointer-unwind-support.c
@@ -53,7 +53,7 @@ u64 get_leaf_frame_caller_aarch64(struct perf_sample *sample, struct thread *thr
sample->user_regs.cache_regs[PERF_REG_ARM64_SP] = 0;
}
- ret = unwind__get_entries(add_entry, &entries, thread, sample, 2);
+ ret = unwind__get_entries(add_entry, &entries, thread, sample, 2, true);
sample->user_regs = old_regs;
if (ret || entries.length != 2)
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index b80048546451359291fc886b6322d4f8c35cb600..95391236f5f6a9103a233d0e8feffb30b49e995a 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2987,7 +2987,7 @@ static int thread__resolve_callchain_unwind(struct thread *thread,
return 0;
return unwind__get_entries(unwind_entry, cursor,
- thread, sample, max_stack);
+ thread, sample, max_stack, false);
}
int thread__resolve_callchain(struct thread *thread,
diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c
index a74b517f74974dc9d1ecef4c1306915ca6c91850..94aa40f6e3482fc13fe13c70be640a19004f8fdd 100644
--- a/tools/perf/util/unwind-libdw.c
+++ b/tools/perf/util/unwind-libdw.c
@@ -200,7 +200,8 @@ frame_callback(Dwfl_Frame *state, void *arg)
bool isactivation;
if (!dwfl_frame_pc(state, &pc, NULL)) {
- pr_err("%s", dwfl_errmsg(-1));
+ if (!ui->best_effort)
+ pr_err("%s", dwfl_errmsg(-1));
return DWARF_CB_ABORT;
}
@@ -208,7 +209,8 @@ frame_callback(Dwfl_Frame *state, void *arg)
report_module(pc, ui);
if (!dwfl_frame_pc(state, &pc, &isactivation)) {
- pr_err("%s", dwfl_errmsg(-1));
+ if (!ui->best_effort)
+ pr_err("%s", dwfl_errmsg(-1));
return DWARF_CB_ABORT;
}
@@ -222,7 +224,8 @@ frame_callback(Dwfl_Frame *state, void *arg)
int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
struct thread *thread,
struct perf_sample *data,
- int max_stack)
+ int max_stack,
+ bool best_effort)
{
struct unwind_info *ui, ui_buf = {
.sample = data,
@@ -231,6 +234,7 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
.cb = cb,
.arg = arg,
.max_stack = max_stack,
+ .best_effort = best_effort
};
Dwarf_Word ip;
int err = -EINVAL, i;
diff --git a/tools/perf/util/unwind-libdw.h b/tools/perf/util/unwind-libdw.h
index 0cbd2650e280e52635f7e0d9058467d633239c5f..8c88bc4f2304b59561ffd482469ca63ce0f531f0 100644
--- a/tools/perf/util/unwind-libdw.h
+++ b/tools/perf/util/unwind-libdw.h
@@ -20,6 +20,7 @@ struct unwind_info {
void *arg;
int max_stack;
int idx;
+ bool best_effort;
struct unwind_entry entries[];
};
diff --git a/tools/perf/util/unwind-libunwind-local.c b/tools/perf/util/unwind-libunwind-local.c
index 71a3533491815749bd1ec84e659d659cba09957c..41e29fc7648ae9f79fe258d731b5cd1172c61cd6 100644
--- a/tools/perf/util/unwind-libunwind-local.c
+++ b/tools/perf/util/unwind-libunwind-local.c
@@ -96,6 +96,7 @@ struct unwind_info {
struct perf_sample *sample;
struct machine *machine;
struct thread *thread;
+ bool best_effort;
};
#define dw_read(ptr, type, end) ({ \
@@ -553,7 +554,8 @@ static int access_reg(unw_addr_space_t __maybe_unused as,
ret = perf_reg_value(&val, &ui->sample->user_regs, id);
if (ret) {
- pr_err("unwind: can't read reg %d\n", regnum);
+ if (!ui->best_effort)
+ pr_err("unwind: can't read reg %d\n", regnum);
return ret;
}
@@ -666,7 +668,7 @@ static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
return -1;
ret = unw_init_remote(&c, addr_space, ui);
- if (ret)
+ if (ret && !ui->best_effort)
display_error(ret);
while (!ret && (unw_step(&c) > 0) && i < max_stack) {
@@ -704,12 +706,14 @@ static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
static int _unwind__get_entries(unwind_entry_cb_t cb, void *arg,
struct thread *thread,
- struct perf_sample *data, int max_stack)
+ struct perf_sample *data, int max_stack,
+ bool best_effort)
{
struct unwind_info ui = {
.sample = data,
.thread = thread,
.machine = thread->maps->machine,
+ .best_effort = best_effort
};
if (!data->user_regs.regs)
diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index e89a5479b361303e8b323182dd5509a18e5ead1b..509c287ee762808061821a9d2c52301e3b6955e4 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -80,9 +80,11 @@ void unwind__finish_access(struct maps *maps)
int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
struct thread *thread,
- struct perf_sample *data, int max_stack)
+ struct perf_sample *data, int max_stack,
+ bool best_effort)
{
if (thread->maps->unwind_libunwind_ops)
- return thread->maps->unwind_libunwind_ops->get_entries(cb, arg, thread, data, max_stack);
+ return thread->maps->unwind_libunwind_ops->get_entries(cb, arg, thread, data,
+ max_stack, best_effort);
return 0;
}
diff --git a/tools/perf/util/unwind.h b/tools/perf/util/unwind.h
index ab8ad469c8de5aea6c7bf437bfee156f1b0ed2ed..b2a03fa5289b37c2744aab105415e8febe250f0b 100644
--- a/tools/perf/util/unwind.h
+++ b/tools/perf/util/unwind.h
@@ -23,13 +23,19 @@ struct unwind_libunwind_ops {
void (*finish_access)(struct maps *maps);
int (*get_entries)(unwind_entry_cb_t cb, void *arg,
struct thread *thread,
- struct perf_sample *data, int max_stack);
+ struct perf_sample *data, int max_stack, bool best_effort);
};
#ifdef HAVE_DWARF_UNWIND_SUPPORT
+/*
+ * When best_effort is set, don't report errors and fail silently. This could
+ * be expanded in the future to be more permissive about things other than
+ * error messages.
+ */
int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
struct thread *thread,
- struct perf_sample *data, int max_stack);
+ struct perf_sample *data, int max_stack,
+ bool best_effort);
/* libunwind specific */
#ifdef HAVE_LIBUNWIND_SUPPORT
#ifndef LIBUNWIND__ARCH_REG_ID
@@ -65,7 +71,8 @@ unwind__get_entries(unwind_entry_cb_t cb __maybe_unused,
void *arg __maybe_unused,
struct thread *thread __maybe_unused,
struct perf_sample *data __maybe_unused,
- int max_stack __maybe_unused)
+ int max_stack __maybe_unused,
+ bool best_effort __maybe_unused)
{
return 0;
}