// SPDX-License-Identifier: GPL-2.0-or-later /* * test_kprobes.c - simple sanity test for *probes * * Copyright IBM Corp. 2008 */ #define pr_fmt(fmt) "Kprobe smoke test: " fmt #include <linux/kernel.h> #include <linux/kprobes.h> #include <linux/random.h> #define div_factor 3 static u32 rand1, preh_val, posth_val; static int errors, handler_errors, num_tests; static u32 (*target)(u32 value); static u32 (*target2)(u32 value); static noinline u32 kprobe_target(u32 value) { return (value / div_factor); } static int kp_pre_handler(struct kprobe *p, struct pt_regs *regs) { if (preemptible()) { handler_errors++; pr_err("pre-handler is preemptible\n"); } preh_val = (rand1 / div_factor); return 0; } static void kp_post_handler(struct kprobe *p, struct pt_regs *regs, unsigned long flags) { if (preemptible()) { handler_errors++; pr_err("post-handler is preemptible\n"); } if (preh_val != (rand1 / div_factor)) { handler_errors++; pr_err("incorrect value in post_handler\n"); } posth_val = preh_val + div_factor; } static struct kprobe kp = { .symbol_name = "kprobe_target", .pre_handler = kp_pre_handler, .post_handler = kp_post_handler }; static int test_kprobe(void) { int ret; ret = register_kprobe(&kp); if (ret < 0) { pr_err("register_kprobe returned %d\n", ret); return ret; } ret = target(rand1); unregister_kprobe(&kp); if (preh_val == 0) { pr_err("kprobe pre_handler not called\n"); handler_errors++; } if (posth_val == 0) { pr_err("kprobe post_handler not called\n"); handler_errors++; } return 0; } static noinline u32 kprobe_target2(u32 value) { return (value / div_factor) + 1; } static int kp_pre_handler2(struct kprobe *p, struct pt_regs *regs) { preh_val = (rand1 / div_factor) + 1; return 0; } static void kp_post_handler2(struct kprobe *p, struct pt_regs *regs, unsigned long flags) { if (preh_val != (rand1 / div_factor) + 1) { handler_errors++; pr_err("incorrect value in post_handler2\n"); } posth_val = preh_val + div_factor; } static struct kprobe kp2 = { .symbol_name = "kprobe_target2", .pre_handler = kp_pre_handler2, .post_handler = kp_post_handler2 }; static int test_kprobes(void) { int ret; struct kprobe *kps[2] = {&kp, &kp2}; /* addr and flags should be cleard for reusing kprobe. */ kp.addr = NULL; kp.flags = 0; ret = register_kprobes(kps, 2); if (ret < 0) { pr_err("register_kprobes returned %d\n", ret); return ret; } preh_val = 0; posth_val = 0; ret = target(rand1); if (preh_val == 0) { pr_err("kprobe pre_handler not called\n"); handler_errors++; } if (posth_val == 0) { pr_err("kprobe post_handler not called\n"); handler_errors++; } preh_val = 0; posth_val = 0; ret = target2(rand1); if (preh_val == 0) { pr_err("kprobe pre_handler2 not called\n"); handler_errors++; } if (posth_val == 0) { pr_err("kprobe post_handler2 not called\n"); handler_errors++; } unregister_kprobes(kps, 2); return 0; } #ifdef CONFIG_KRETPROBES static u32 krph_val; static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs) { if (preemptible()) { handler_errors++; pr_err("kretprobe entry handler is preemptible\n"); } krph_val = (rand1 / div_factor); return 0; } static int return_handler(struct kretprobe_instance *ri, struct pt_regs *regs) { unsigned long ret = regs_return_value(regs); if (preemptible()) { handler_errors++; pr_err("kretprobe return handler is preemptible\n"); } if (ret != (rand1 / div_factor)) { handler_errors++; pr_err("incorrect value in kretprobe handler\n"); } if (krph_val == 0) { handler_errors++; pr_err("call to kretprobe entry handler failed\n"); } krph_val = rand1; return 0; } static struct kretprobe rp = { .handler = return_handler, .entry_handler = entry_handler, .kp.symbol_name = "kprobe_target" }; static int test_kretprobe(void) { int ret; ret = register_kretprobe(&rp); if (ret < 0) { pr_err("register_kretprobe returned %d\n", ret); return ret; } ret = target(rand1); unregister_kretprobe(&rp); if (krph_val != rand1) { pr_err("kretprobe handler not called\n"); handler_errors++; } return 0; } static int return_handler2(struct kretprobe_instance *ri, struct pt_regs *regs) { unsigned long ret = regs_return_value(regs); if (ret != (rand1 / div_factor) + 1) { handler_errors++; pr_err("incorrect value in kretprobe handler2\n"); } if (krph_val == 0) { handler_errors++; pr_err("call to kretprobe entry handler failed\n"); } krph_val = rand1; return 0; } static struct kretprobe rp2 = { .handler = return_handler2, .entry_handler = entry_handler, .kp.symbol_name = "kprobe_target2" }; static int test_kretprobes(void) { int ret; struct kretprobe *rps[2] = {&rp, &rp2}; /* addr and flags should be cleard for reusing kprobe. */ rp.kp.addr = NULL; rp.kp.flags = 0; ret = register_kretprobes(rps, 2); if (ret < 0) { pr_err("register_kretprobe returned %d\n", ret); return ret; } krph_val = 0; ret = target(rand1); if (krph_val != rand1) { pr_err("kretprobe handler not called\n"); handler_errors++; } krph_val = 0; ret = target2(rand1); if (krph_val != rand1) { pr_err("kretprobe handler2 not called\n"); handler_errors++; } unregister_kretprobes(rps, 2); return 0; } #endif /* CONFIG_KRETPROBES */ int init_test_probes(void) { int ret; target = kprobe_target; target2 = kprobe_target2; do { rand1 = prandom_u32(); } while (rand1 <= div_factor); pr_info("started\n"); num_tests++; ret = test_kprobe(); if (ret < 0) errors++; num_tests++; ret = test_kprobes(); if (ret < 0) errors++; #ifdef CONFIG_KRETPROBES num_tests++; ret = test_kretprobe(); if (ret < 0) errors++; num_tests++; ret = test_kretprobes(); if (ret < 0) errors++; #endif /* CONFIG_KRETPROBES */ if (errors) pr_err("BUG: %d out of %d tests failed\n", errors, num_tests); else if (handler_errors) pr_err("BUG: %d error(s) running handlers\n", handler_errors); else pr_info("passed successfully\n"); return 0; }