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x86/fgraph,bpf: Fix ORC stack unwind from kprobe_multi #10846

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8588d43
x86/fgraph: Fix return_to_handler regs.rsp value
olsajiri Jan 26, 2026
eb56a59
x86/fgraph,bpf: Switch kprobe_multi program stack unwind to hw_regs path
olsajiri Jan 26, 2026
d3c7ba6
selftests/bpf: Fix kprobe multi stacktrace_ips test
olsajiri Jan 26, 2026
5aadd4b
selftests/bpf: Add stacktrace ips test for kprobe/kretprobe
olsajiri Jan 26, 2026
a066392
selftests/bpf: Add stacktrace ips test for fentry/fexit
olsajiri Jan 26, 2026
bf46b41
selftests/bpf: Allow to benchmark trigger with stacktrace
olsajiri Jan 26, 2026
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2 changes: 1 addition & 1 deletion arch/x86/include/asm/ftrace.h
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Original file line number Diff line number Diff line change
Expand Up @@ -57,7 +57,7 @@ arch_ftrace_get_regs(struct ftrace_regs *fregs)
}

#define arch_ftrace_partial_regs(regs) do { \
regs->flags &= ~X86_EFLAGS_FIXED; \
regs->flags |= X86_EFLAGS_FIXED; \
regs->cs = __KERNEL_CS; \
} while (0)

Expand Down
5 changes: 4 additions & 1 deletion arch/x86/kernel/ftrace_64.S
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Original file line number Diff line number Diff line change
Expand Up @@ -364,6 +364,9 @@ SYM_CODE_START(return_to_handler)
UNWIND_HINT_UNDEFINED
ANNOTATE_NOENDBR

/* Store original rsp for pt_regs.sp value. */
movq %rsp, %rdi

/* Restore return_to_handler value that got eaten by previous ret instruction. */
subq $8, %rsp
UNWIND_HINT_FUNC
Expand All @@ -374,7 +377,7 @@ SYM_CODE_START(return_to_handler)
movq %rax, RAX(%rsp)
movq %rdx, RDX(%rsp)
movq %rbp, RBP(%rsp)
movq %rsp, RSP(%rsp)
movq %rdi, RSP(%rsp)
movq %rsp, %rdi

call ftrace_return_to_handler
Expand Down
4 changes: 4 additions & 0 deletions tools/testing/selftests/bpf/bench.c
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Original file line number Diff line number Diff line change
Expand Up @@ -265,6 +265,7 @@ static const struct argp_option opts[] = {
{ "verbose", 'v', NULL, 0, "Verbose debug output"},
{ "affinity", 'a', NULL, 0, "Set consumer/producer thread affinity"},
{ "quiet", 'q', NULL, 0, "Be more quiet"},
{ "stacktrace", 's', NULL, 0, "Get stack trace"},
{ "prod-affinity", ARG_PROD_AFFINITY_SET, "CPUSET", 0,
"Set of CPUs for producer threads; implies --affinity"},
{ "cons-affinity", ARG_CONS_AFFINITY_SET, "CPUSET", 0,
Expand Down Expand Up @@ -350,6 +351,9 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
case 'q':
env.quiet = true;
break;
case 's':
env.stacktrace = true;
break;
case ARG_PROD_AFFINITY_SET:
env.affinity = true;
if (parse_num_list(arg, &env.prod_cpus.cpus,
Expand Down
1 change: 1 addition & 0 deletions tools/testing/selftests/bpf/bench.h
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@ struct env {
bool list;
bool affinity;
bool quiet;
bool stacktrace;
int consumer_cnt;
int producer_cnt;
int nr_cpus;
Expand Down
1 change: 1 addition & 0 deletions tools/testing/selftests/bpf/benchs/bench_trigger.c
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Original file line number Diff line number Diff line change
Expand Up @@ -146,6 +146,7 @@ static void setup_ctx(void)
bpf_program__set_autoload(ctx.skel->progs.trigger_driver, true);

ctx.skel->rodata->batch_iters = args.batch_iters;
ctx.skel->rodata->stacktrace = env.stacktrace;
}

static void load_ctx(void)
Expand Down
120 changes: 115 additions & 5 deletions tools/testing/selftests/bpf/prog_tests/stacktrace_ips.c
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Original file line number Diff line number Diff line change
Expand Up @@ -74,11 +74,20 @@ static void test_stacktrace_ips_kprobe_multi(bool retprobe)

load_kallsyms();

check_stacktrace_ips(bpf_map__fd(skel->maps.stackmap), skel->bss->stack_key, 4,
ksym_get_addr("bpf_testmod_stacktrace_test_3"),
ksym_get_addr("bpf_testmod_stacktrace_test_2"),
ksym_get_addr("bpf_testmod_stacktrace_test_1"),
ksym_get_addr("bpf_testmod_test_read"));
if (retprobe) {
check_stacktrace_ips(bpf_map__fd(skel->maps.stackmap), skel->bss->stack_key, 4,
ksym_get_addr("bpf_testmod_stacktrace_test_3"),
ksym_get_addr("bpf_testmod_stacktrace_test_2"),
ksym_get_addr("bpf_testmod_stacktrace_test_1"),
ksym_get_addr("bpf_testmod_test_read"));
} else {
check_stacktrace_ips(bpf_map__fd(skel->maps.stackmap), skel->bss->stack_key, 5,
ksym_get_addr("bpf_testmod_stacktrace_test"),
ksym_get_addr("bpf_testmod_stacktrace_test_3"),
ksym_get_addr("bpf_testmod_stacktrace_test_2"),
ksym_get_addr("bpf_testmod_stacktrace_test_1"),
ksym_get_addr("bpf_testmod_test_read"));
}

cleanup:
stacktrace_ips__destroy(skel);
Expand Down Expand Up @@ -128,6 +137,99 @@ static void test_stacktrace_ips_raw_tp(void)
stacktrace_ips__destroy(skel);
}

static void test_stacktrace_ips_kprobe(bool retprobe)
{
LIBBPF_OPTS(bpf_kprobe_opts, opts,
.retprobe = retprobe
);
LIBBPF_OPTS(bpf_test_run_opts, topts);
struct stacktrace_ips *skel;

skel = stacktrace_ips__open_and_load();
if (!ASSERT_OK_PTR(skel, "stacktrace_ips__open_and_load"))
return;

if (!skel->kconfig->CONFIG_UNWINDER_ORC) {
test__skip();
goto cleanup;
}

skel->links.kprobe_test = bpf_program__attach_kprobe_opts(
skel->progs.kprobe_test,
"bpf_testmod_stacktrace_test", &opts);
if (!ASSERT_OK_PTR(skel->links.kprobe_test, "bpf_program__attach_kprobe_opts"))
goto cleanup;

trigger_module_test_read(1);

load_kallsyms();

if (retprobe) {
check_stacktrace_ips(bpf_map__fd(skel->maps.stackmap), skel->bss->stack_key, 4,
ksym_get_addr("bpf_testmod_stacktrace_test_3"),
ksym_get_addr("bpf_testmod_stacktrace_test_2"),
ksym_get_addr("bpf_testmod_stacktrace_test_1"),
ksym_get_addr("bpf_testmod_test_read"));
} else {
check_stacktrace_ips(bpf_map__fd(skel->maps.stackmap), skel->bss->stack_key, 5,
ksym_get_addr("bpf_testmod_stacktrace_test"),
ksym_get_addr("bpf_testmod_stacktrace_test_3"),
ksym_get_addr("bpf_testmod_stacktrace_test_2"),
ksym_get_addr("bpf_testmod_stacktrace_test_1"),
ksym_get_addr("bpf_testmod_test_read"));
}

cleanup:
stacktrace_ips__destroy(skel);
}

static void test_stacktrace_ips_trampoline(bool retprobe)
{
LIBBPF_OPTS(bpf_test_run_opts, topts);
struct stacktrace_ips *skel;

skel = stacktrace_ips__open_and_load();
if (!ASSERT_OK_PTR(skel, "stacktrace_ips__open_and_load"))
return;

if (!skel->kconfig->CONFIG_UNWINDER_ORC) {
test__skip();
goto cleanup;
}

if (retprobe) {
skel->links.fexit_test = bpf_program__attach_trace(skel->progs.fexit_test);
if (!ASSERT_OK_PTR(skel->links.fexit_test, "bpf_program__attach_trace"))
goto cleanup;
} else {
skel->links.fentry_test = bpf_program__attach_trace(skel->progs.fentry_test);
if (!ASSERT_OK_PTR(skel->links.fentry_test, "bpf_program__attach_trace"))
goto cleanup;
}

trigger_module_test_read(1);

load_kallsyms();

if (retprobe) {
check_stacktrace_ips(bpf_map__fd(skel->maps.stackmap), skel->bss->stack_key, 4,
ksym_get_addr("bpf_testmod_stacktrace_test_3"),
ksym_get_addr("bpf_testmod_stacktrace_test_2"),
ksym_get_addr("bpf_testmod_stacktrace_test_1"),
ksym_get_addr("bpf_testmod_test_read"));
} else {
check_stacktrace_ips(bpf_map__fd(skel->maps.stackmap), skel->bss->stack_key, 5,
ksym_get_addr("bpf_testmod_stacktrace_test"),
ksym_get_addr("bpf_testmod_stacktrace_test_3"),
ksym_get_addr("bpf_testmod_stacktrace_test_2"),
ksym_get_addr("bpf_testmod_stacktrace_test_1"),
ksym_get_addr("bpf_testmod_test_read"));
}

cleanup:
stacktrace_ips__destroy(skel);
}

static void __test_stacktrace_ips(void)
{
if (test__start_subtest("kprobe_multi"))
Expand All @@ -136,6 +238,14 @@ static void __test_stacktrace_ips(void)
test_stacktrace_ips_kprobe_multi(true);
if (test__start_subtest("raw_tp"))
test_stacktrace_ips_raw_tp();
if (test__start_subtest("kprobe"))
test_stacktrace_ips_kprobe(false);
if (test__start_subtest("kretprobe"))
test_stacktrace_ips_kprobe(true);
if (test__start_subtest("fentry"))
test_stacktrace_ips_trampoline(false);
if (test__start_subtest("fexit"))
test_stacktrace_ips_trampoline(true);
}
#else
static void __test_stacktrace_ips(void)
Expand Down
27 changes: 27 additions & 0 deletions tools/testing/selftests/bpf/progs/stacktrace_ips.c
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,13 @@ int unused(void)

__u32 stack_key;

SEC("kprobe")
int kprobe_test(struct pt_regs *ctx)
{
stack_key = bpf_get_stackid(ctx, &stackmap, 0);
return 0;
}

SEC("kprobe.multi")
int kprobe_multi_test(struct pt_regs *ctx)
{
Expand All @@ -46,4 +53,24 @@ int rawtp_test(void *ctx)
return 0;
}

SEC("fentry/bpf_testmod_stacktrace_test")
int fentry_test(struct pt_regs *ctx)
{
/*
* Skip 2 bpf_program/trampoline stack entries:
* - bpf_prog_bd1f7a949f55fb03_fentry_test
* - bpf_trampoline_182536277701
*/
stack_key = bpf_get_stackid(ctx, &stackmap, 2);
return 0;
}

SEC("fexit/bpf_testmod_stacktrace_test")
int fexit_test(struct pt_regs *ctx)
{
/* Skip 2 bpf_program/trampoline stack entries, check fentry_test. */
stack_key = bpf_get_stackid(ctx, &stackmap, 2);
return 0;
}

char _license[] SEC("license") = "GPL";
46 changes: 37 additions & 9 deletions tools/testing/selftests/bpf/progs/trigger_bench.c
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,34 @@ static __always_inline void inc_counter(void)
__sync_add_and_fetch(&hits[cpu & CPU_MASK].value, 1);
}

volatile const int stacktrace;

typedef __u64 stack_trace_t[128];

struct {
__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
__uint(max_entries, 1);
__type(key, __u32);
__type(value, stack_trace_t);
} stack_heap SEC(".maps");

static __always_inline void do_stacktrace(void *ctx)
{
if (!stacktrace)
return;

__u64 *ptr = bpf_map_lookup_elem(&stack_heap, &(__u32){0});

if (ptr)
bpf_get_stack(ctx, ptr, sizeof(stack_trace_t), 0);
}

static __always_inline void handle(void *ctx)
{
inc_counter();
do_stacktrace(ctx);
}

SEC("?uprobe")
int bench_trigger_uprobe(void *ctx)
{
Expand Down Expand Up @@ -81,21 +109,21 @@ int trigger_driver_kfunc(void *ctx)
SEC("?kprobe/bpf_get_numa_node_id")
int bench_trigger_kprobe(void *ctx)
{
inc_counter();
handle(ctx);
return 0;
}

SEC("?kretprobe/bpf_get_numa_node_id")
int bench_trigger_kretprobe(void *ctx)
{
inc_counter();
handle(ctx);
return 0;
}

SEC("?kprobe.multi/bpf_get_numa_node_id")
int bench_trigger_kprobe_multi(void *ctx)
{
inc_counter();
handle(ctx);
return 0;
}

Expand All @@ -108,7 +136,7 @@ int bench_kprobe_multi_empty(void *ctx)
SEC("?kretprobe.multi/bpf_get_numa_node_id")
int bench_trigger_kretprobe_multi(void *ctx)
{
inc_counter();
handle(ctx);
return 0;
}

Expand All @@ -121,34 +149,34 @@ int bench_kretprobe_multi_empty(void *ctx)
SEC("?fentry/bpf_get_numa_node_id")
int bench_trigger_fentry(void *ctx)
{
inc_counter();
handle(ctx);
return 0;
}

SEC("?fexit/bpf_get_numa_node_id")
int bench_trigger_fexit(void *ctx)
{
inc_counter();
handle(ctx);
return 0;
}

SEC("?fmod_ret/bpf_modify_return_test_tp")
int bench_trigger_fmodret(void *ctx)
{
inc_counter();
handle(ctx);
return -22;
}

SEC("?tp/bpf_test_run/bpf_trigger_tp")
int bench_trigger_tp(void *ctx)
{
inc_counter();
handle(ctx);
return 0;
}

SEC("?raw_tp/bpf_trigger_tp")
int bench_trigger_rawtp(void *ctx)
{
inc_counter();
handle(ctx);
return 0;
}
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