| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Kprobes-based tracing events |
| * |
| * Created by Masami Hiramatsu <mhiramat@redhat.com> |
| * |
| */ |
| #define pr_fmt(fmt) "trace_kprobe: " fmt |
| |
| #include <linux/bpf-cgroup.h> |
| #include <linux/security.h> |
| #include <linux/module.h> |
| #include <linux/uaccess.h> |
| #include <linux/rculist.h> |
| #include <linux/error-injection.h> |
| |
| #include <asm/setup.h> /* for COMMAND_LINE_SIZE */ |
| |
| #include "trace_dynevent.h" |
| #include "trace_kprobe_selftest.h" |
| #include "trace_probe.h" |
| #include "trace_probe_tmpl.h" |
| |
| #define KPROBE_EVENT_SYSTEM "kprobes" |
| #define KRETPROBE_MAXACTIVE_MAX 4096 |
| |
| /* Kprobe early definition from command line */ |
| static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata; |
| |
| static int __init set_kprobe_boot_events(char *str) |
| { |
| strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE); |
| disable_tracing_selftest("running kprobe events"); |
| |
| return 1; |
| } |
| __setup("kprobe_event=", set_kprobe_boot_events); |
| |
| static int trace_kprobe_create(const char *raw_command); |
| static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev); |
| static int trace_kprobe_release(struct dyn_event *ev); |
| static bool trace_kprobe_is_busy(struct dyn_event *ev); |
| static bool trace_kprobe_match(const char *system, const char *event, |
| int argc, const char **argv, struct dyn_event *ev); |
| |
| static struct dyn_event_operations trace_kprobe_ops = { |
| .create = trace_kprobe_create, |
| .show = trace_kprobe_show, |
| .is_busy = trace_kprobe_is_busy, |
| .free = trace_kprobe_release, |
| .match = trace_kprobe_match, |
| }; |
| |
| /* |
| * Kprobe event core functions |
| */ |
| struct trace_kprobe { |
| struct dyn_event devent; |
| struct kretprobe rp; /* Use rp.kp for kprobe use */ |
| unsigned long __percpu *nhit; |
| const char *symbol; /* symbol name */ |
| struct trace_probe tp; |
| }; |
| |
| static bool is_trace_kprobe(struct dyn_event *ev) |
| { |
| return ev->ops == &trace_kprobe_ops; |
| } |
| |
| static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev) |
| { |
| return container_of(ev, struct trace_kprobe, devent); |
| } |
| |
| /** |
| * for_each_trace_kprobe - iterate over the trace_kprobe list |
| * @pos: the struct trace_kprobe * for each entry |
| * @dpos: the struct dyn_event * to use as a loop cursor |
| */ |
| #define for_each_trace_kprobe(pos, dpos) \ |
| for_each_dyn_event(dpos) \ |
| if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos))) |
| |
| static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk) |
| { |
| return tk->rp.handler != NULL; |
| } |
| |
| static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk) |
| { |
| return tk->symbol ? tk->symbol : "unknown"; |
| } |
| |
| static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk) |
| { |
| return tk->rp.kp.offset; |
| } |
| |
| static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk) |
| { |
| return kprobe_gone(&tk->rp.kp); |
| } |
| |
| static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk, |
| struct module *mod) |
| { |
| int len = strlen(module_name(mod)); |
| const char *name = trace_kprobe_symbol(tk); |
| |
| return strncmp(module_name(mod), name, len) == 0 && name[len] == ':'; |
| } |
| |
| static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) |
| { |
| char *p; |
| bool ret; |
| |
| if (!tk->symbol) |
| return false; |
| p = strchr(tk->symbol, ':'); |
| if (!p) |
| return true; |
| *p = '\0'; |
| rcu_read_lock_sched(); |
| ret = !!find_module(tk->symbol); |
| rcu_read_unlock_sched(); |
| *p = ':'; |
| |
| return ret; |
| } |
| |
| static bool trace_kprobe_is_busy(struct dyn_event *ev) |
| { |
| struct trace_kprobe *tk = to_trace_kprobe(ev); |
| |
| return trace_probe_is_enabled(&tk->tp); |
| } |
| |
| static bool trace_kprobe_match_command_head(struct trace_kprobe *tk, |
| int argc, const char **argv) |
| { |
| char buf[MAX_ARGSTR_LEN + 1]; |
| |
| if (!argc) |
| return true; |
| |
| if (!tk->symbol) |
| snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr); |
| else if (tk->rp.kp.offset) |
| snprintf(buf, sizeof(buf), "%s+%u", |
| trace_kprobe_symbol(tk), tk->rp.kp.offset); |
| else |
| snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk)); |
| if (strcmp(buf, argv[0])) |
| return false; |
| argc--; argv++; |
| |
| return trace_probe_match_command_args(&tk->tp, argc, argv); |
| } |
| |
| static bool trace_kprobe_match(const char *system, const char *event, |
| int argc, const char **argv, struct dyn_event *ev) |
| { |
| struct trace_kprobe *tk = to_trace_kprobe(ev); |
| |
| return strcmp(trace_probe_name(&tk->tp), event) == 0 && |
| (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) && |
| trace_kprobe_match_command_head(tk, argc, argv); |
| } |
| |
| static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk) |
| { |
| unsigned long nhit = 0; |
| int cpu; |
| |
| for_each_possible_cpu(cpu) |
| nhit += *per_cpu_ptr(tk->nhit, cpu); |
| |
| return nhit; |
| } |
| |
| static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk) |
| { |
| return !(list_empty(&tk->rp.kp.list) && |
| hlist_unhashed(&tk->rp.kp.hlist)); |
| } |
| |
| /* Return 0 if it fails to find the symbol address */ |
| static nokprobe_inline |
| unsigned long trace_kprobe_address(struct trace_kprobe *tk) |
| { |
| unsigned long addr; |
| |
| if (tk->symbol) { |
| addr = (unsigned long) |
| kallsyms_lookup_name(trace_kprobe_symbol(tk)); |
| if (addr) |
| addr += tk->rp.kp.offset; |
| } else { |
| addr = (unsigned long)tk->rp.kp.addr; |
| } |
| return addr; |
| } |
| |
| static nokprobe_inline struct trace_kprobe * |
| trace_kprobe_primary_from_call(struct trace_event_call *call) |
| { |
| struct trace_probe *tp; |
| |
| tp = trace_probe_primary_from_call(call); |
| if (WARN_ON_ONCE(!tp)) |
| return NULL; |
| |
| return container_of(tp, struct trace_kprobe, tp); |
| } |
| |
| bool trace_kprobe_on_func_entry(struct trace_event_call *call) |
| { |
| struct trace_kprobe *tk = trace_kprobe_primary_from_call(call); |
| |
| return tk ? (kprobe_on_func_entry(tk->rp.kp.addr, |
| tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name, |
| tk->rp.kp.addr ? 0 : tk->rp.kp.offset) == 0) : false; |
| } |
| |
| bool trace_kprobe_error_injectable(struct trace_event_call *call) |
| { |
| struct trace_kprobe *tk = trace_kprobe_primary_from_call(call); |
| |
| return tk ? within_error_injection_list(trace_kprobe_address(tk)) : |
| false; |
| } |
| |
| static int register_kprobe_event(struct trace_kprobe *tk); |
| static int unregister_kprobe_event(struct trace_kprobe *tk); |
| |
| static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs); |
| static int kretprobe_dispatcher(struct kretprobe_instance *ri, |
| struct pt_regs *regs); |
| |
| static void free_trace_kprobe(struct trace_kprobe *tk) |
| { |
| if (tk) { |
| trace_probe_cleanup(&tk->tp); |
| kfree(tk->symbol); |
| free_percpu(tk->nhit); |
| kfree(tk); |
| } |
| } |
| |
| /* |
| * Allocate new trace_probe and initialize it (including kprobes). |
| */ |
| static struct trace_kprobe *alloc_trace_kprobe(const char *group, |
| const char *event, |
| void *addr, |
| const char *symbol, |
| unsigned long offs, |
| int maxactive, |
| int nargs, bool is_return) |
| { |
| struct trace_kprobe *tk; |
| int ret = -ENOMEM; |
| |
| tk = kzalloc(struct_size(tk, tp.args, nargs), GFP_KERNEL); |
| if (!tk) |
| return ERR_PTR(ret); |
| |
| tk->nhit = alloc_percpu(unsigned long); |
| if (!tk->nhit) |
| goto error; |
| |
| if (symbol) { |
| tk->symbol = kstrdup(symbol, GFP_KERNEL); |
| if (!tk->symbol) |
| goto error; |
| tk->rp.kp.symbol_name = tk->symbol; |
| tk->rp.kp.offset = offs; |
| } else |
| tk->rp.kp.addr = addr; |
| |
| if (is_return) |
| tk->rp.handler = kretprobe_dispatcher; |
| else |
| tk->rp.kp.pre_handler = kprobe_dispatcher; |
| |
| tk->rp.maxactive = maxactive; |
| INIT_HLIST_NODE(&tk->rp.kp.hlist); |
| INIT_LIST_HEAD(&tk->rp.kp.list); |
| |
| ret = trace_probe_init(&tk->tp, event, group, false); |
| if (ret < 0) |
| goto error; |
| |
| dyn_event_init(&tk->devent, &trace_kprobe_ops); |
| return tk; |
| error: |
| free_trace_kprobe(tk); |
| return ERR_PTR(ret); |
| } |
| |
| static struct trace_kprobe *find_trace_kprobe(const char *event, |
| const char *group) |
| { |
| struct dyn_event *pos; |
| struct trace_kprobe *tk; |
| |
| for_each_trace_kprobe(tk, pos) |
| if (strcmp(trace_probe_name(&tk->tp), event) == 0 && |
| strcmp(trace_probe_group_name(&tk->tp), group) == 0) |
| return tk; |
| return NULL; |
| } |
| |
| static inline int __enable_trace_kprobe(struct trace_kprobe *tk) |
| { |
| int ret = 0; |
| |
| if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) { |
| if (trace_kprobe_is_return(tk)) |
| ret = enable_kretprobe(&tk->rp); |
| else |
| ret = enable_kprobe(&tk->rp.kp); |
| } |
| |
| return ret; |
| } |
| |
| static void __disable_trace_kprobe(struct trace_probe *tp) |
| { |
| struct trace_kprobe *tk; |
| |
| list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) { |
| if (!trace_kprobe_is_registered(tk)) |
| continue; |
| if (trace_kprobe_is_return(tk)) |
| disable_kretprobe(&tk->rp); |
| else |
| disable_kprobe(&tk->rp.kp); |
| } |
| } |
| |
| /* |
| * Enable trace_probe |
| * if the file is NULL, enable "perf" handler, or enable "trace" handler. |
| */ |
| static int enable_trace_kprobe(struct trace_event_call *call, |
| struct trace_event_file *file) |
| { |
| struct trace_probe *tp; |
| struct trace_kprobe *tk; |
| bool enabled; |
| int ret = 0; |
| |
| tp = trace_probe_primary_from_call(call); |
| if (WARN_ON_ONCE(!tp)) |
| return -ENODEV; |
| enabled = trace_probe_is_enabled(tp); |
| |
| /* This also changes "enabled" state */ |
| if (file) { |
| ret = trace_probe_add_file(tp, file); |
| if (ret) |
| return ret; |
| } else |
| trace_probe_set_flag(tp, TP_FLAG_PROFILE); |
| |
| if (enabled) |
| return 0; |
| |
| list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) { |
| if (trace_kprobe_has_gone(tk)) |
| continue; |
| ret = __enable_trace_kprobe(tk); |
| if (ret) |
| break; |
| enabled = true; |
| } |
| |
| if (ret) { |
| /* Failed to enable one of them. Roll back all */ |
| if (enabled) |
| __disable_trace_kprobe(tp); |
| if (file) |
| trace_probe_remove_file(tp, file); |
| else |
| trace_probe_clear_flag(tp, TP_FLAG_PROFILE); |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * Disable trace_probe |
| * if the file is NULL, disable "perf" handler, or disable "trace" handler. |
| */ |
| static int disable_trace_kprobe(struct trace_event_call *call, |
| struct trace_event_file *file) |
| { |
| struct trace_probe *tp; |
| |
| tp = trace_probe_primary_from_call(call); |
| if (WARN_ON_ONCE(!tp)) |
| return -ENODEV; |
| |
| if (file) { |
| if (!trace_probe_get_file_link(tp, file)) |
| return -ENOENT; |
| if (!trace_probe_has_single_file(tp)) |
| goto out; |
| trace_probe_clear_flag(tp, TP_FLAG_TRACE); |
| } else |
| trace_probe_clear_flag(tp, TP_FLAG_PROFILE); |
| |
| if (!trace_probe_is_enabled(tp)) |
| __disable_trace_kprobe(tp); |
| |
| out: |
| if (file) |
| /* |
| * Synchronization is done in below function. For perf event, |
| * file == NULL and perf_trace_event_unreg() calls |
| * tracepoint_synchronize_unregister() to ensure synchronize |
| * event. We don't need to care about it. |
| */ |
| trace_probe_remove_file(tp, file); |
| |
| return 0; |
| } |
| |
| #if defined(CONFIG_DYNAMIC_FTRACE) && \ |
| !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE) |
| static bool __within_notrace_func(unsigned long addr) |
| { |
| unsigned long offset, size; |
| |
| if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset)) |
| return false; |
| |
| /* Get the entry address of the target function */ |
| addr -= offset; |
| |
| /* |
| * Since ftrace_location_range() does inclusive range check, we need |
| * to subtract 1 byte from the end address. |
| */ |
| return !ftrace_location_range(addr, addr + size - 1); |
| } |
| |
| static bool within_notrace_func(struct trace_kprobe *tk) |
| { |
| unsigned long addr = trace_kprobe_address(tk); |
| char symname[KSYM_NAME_LEN], *p; |
| |
| if (!__within_notrace_func(addr)) |
| return false; |
| |
| /* Check if the address is on a suffixed-symbol */ |
| if (!lookup_symbol_name(addr, symname)) { |
| p = strchr(symname, '.'); |
| if (!p) |
| return true; |
| *p = '\0'; |
| addr = (unsigned long)kprobe_lookup_name(symname, 0); |
| if (addr) |
| return __within_notrace_func(addr); |
| } |
| |
| return true; |
| } |
| #else |
| #define within_notrace_func(tk) (false) |
| #endif |
| |
| /* Internal register function - just handle k*probes and flags */ |
| static int __register_trace_kprobe(struct trace_kprobe *tk) |
| { |
| int i, ret; |
| |
| ret = security_locked_down(LOCKDOWN_KPROBES); |
| if (ret) |
| return ret; |
| |
| if (trace_kprobe_is_registered(tk)) |
| return -EINVAL; |
| |
| if (within_notrace_func(tk)) { |
| pr_warn("Could not probe notrace function %s\n", |
| trace_kprobe_symbol(tk)); |
| return -EINVAL; |
| } |
| |
| for (i = 0; i < tk->tp.nr_args; i++) { |
| ret = traceprobe_update_arg(&tk->tp.args[i]); |
| if (ret) |
| return ret; |
| } |
| |
| /* Set/clear disabled flag according to tp->flag */ |
| if (trace_probe_is_enabled(&tk->tp)) |
| tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED; |
| else |
| tk->rp.kp.flags |= KPROBE_FLAG_DISABLED; |
| |
| if (trace_kprobe_is_return(tk)) |
| ret = register_kretprobe(&tk->rp); |
| else |
| ret = register_kprobe(&tk->rp.kp); |
| |
| return ret; |
| } |
| |
| /* Internal unregister function - just handle k*probes and flags */ |
| static void __unregister_trace_kprobe(struct trace_kprobe *tk) |
| { |
| if (trace_kprobe_is_registered(tk)) { |
| if (trace_kprobe_is_return(tk)) |
| unregister_kretprobe(&tk->rp); |
| else |
| unregister_kprobe(&tk->rp.kp); |
| /* Cleanup kprobe for reuse and mark it unregistered */ |
| INIT_HLIST_NODE(&tk->rp.kp.hlist); |
| INIT_LIST_HEAD(&tk->rp.kp.list); |
| if (tk->rp.kp.symbol_name) |
| tk->rp.kp.addr = NULL; |
| } |
| } |
| |
| /* Unregister a trace_probe and probe_event */ |
| static int unregister_trace_kprobe(struct trace_kprobe *tk) |
| { |
| /* If other probes are on the event, just unregister kprobe */ |
| if (trace_probe_has_sibling(&tk->tp)) |
| goto unreg; |
| |
| /* Enabled event can not be unregistered */ |
| if (trace_probe_is_enabled(&tk->tp)) |
| return -EBUSY; |
| |
| /* If there's a reference to the dynamic event */ |
| if (trace_event_dyn_busy(trace_probe_event_call(&tk->tp))) |
| return -EBUSY; |
| |
| /* Will fail if probe is being used by ftrace or perf */ |
| if (unregister_kprobe_event(tk)) |
| return -EBUSY; |
| |
| unreg: |
| __unregister_trace_kprobe(tk); |
| dyn_event_remove(&tk->devent); |
| trace_probe_unlink(&tk->tp); |
| |
| return 0; |
| } |
| |
| static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig, |
| struct trace_kprobe *comp) |
| { |
| struct trace_probe_event *tpe = orig->tp.event; |
| int i; |
| |
| list_for_each_entry(orig, &tpe->probes, tp.list) { |
| if (strcmp(trace_kprobe_symbol(orig), |
| trace_kprobe_symbol(comp)) || |
| trace_kprobe_offset(orig) != trace_kprobe_offset(comp)) |
| continue; |
| |
| /* |
| * trace_probe_compare_arg_type() ensured that nr_args and |
| * each argument name and type are same. Let's compare comm. |
| */ |
| for (i = 0; i < orig->tp.nr_args; i++) { |
| if (strcmp(orig->tp.args[i].comm, |
| comp->tp.args[i].comm)) |
| break; |
| } |
| |
| if (i == orig->tp.nr_args) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to) |
| { |
| int ret; |
| |
| ret = trace_probe_compare_arg_type(&tk->tp, &to->tp); |
| if (ret) { |
| /* Note that argument starts index = 2 */ |
| trace_probe_log_set_index(ret + 1); |
| trace_probe_log_err(0, DIFF_ARG_TYPE); |
| return -EEXIST; |
| } |
| if (trace_kprobe_has_same_kprobe(to, tk)) { |
| trace_probe_log_set_index(0); |
| trace_probe_log_err(0, SAME_PROBE); |
| return -EEXIST; |
| } |
| |
| /* Append to existing event */ |
| ret = trace_probe_append(&tk->tp, &to->tp); |
| if (ret) |
| return ret; |
| |
| /* Register k*probe */ |
| ret = __register_trace_kprobe(tk); |
| if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { |
| pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); |
| ret = 0; |
| } |
| |
| if (ret) |
| trace_probe_unlink(&tk->tp); |
| else |
| dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp)); |
| |
| return ret; |
| } |
| |
| /* Register a trace_probe and probe_event */ |
| static int register_trace_kprobe(struct trace_kprobe *tk) |
| { |
| struct trace_kprobe *old_tk; |
| int ret; |
| |
| mutex_lock(&event_mutex); |
| |
| old_tk = find_trace_kprobe(trace_probe_name(&tk->tp), |
| trace_probe_group_name(&tk->tp)); |
| if (old_tk) { |
| if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) { |
| trace_probe_log_set_index(0); |
| trace_probe_log_err(0, DIFF_PROBE_TYPE); |
| ret = -EEXIST; |
| } else { |
| ret = append_trace_kprobe(tk, old_tk); |
| } |
| goto end; |
| } |
| |
| /* Register new event */ |
| ret = register_kprobe_event(tk); |
| if (ret) { |
| if (ret == -EEXIST) { |
| trace_probe_log_set_index(0); |
| trace_probe_log_err(0, EVENT_EXIST); |
| } else |
| pr_warn("Failed to register probe event(%d)\n", ret); |
| goto end; |
| } |
| |
| /* Register k*probe */ |
| ret = __register_trace_kprobe(tk); |
| if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { |
| pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); |
| ret = 0; |
| } |
| |
| if (ret < 0) |
| unregister_kprobe_event(tk); |
| else |
| dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp)); |
| |
| end: |
| mutex_unlock(&event_mutex); |
| return ret; |
| } |
| |
| /* Module notifier call back, checking event on the module */ |
| static int trace_kprobe_module_callback(struct notifier_block *nb, |
| unsigned long val, void *data) |
| { |
| struct module *mod = data; |
| struct dyn_event *pos; |
| struct trace_kprobe *tk; |
| int ret; |
| |
| if (val != MODULE_STATE_COMING) |
| return NOTIFY_DONE; |
| |
| /* Update probes on coming module */ |
| mutex_lock(&event_mutex); |
| for_each_trace_kprobe(tk, pos) { |
| if (trace_kprobe_within_module(tk, mod)) { |
| /* Don't need to check busy - this should have gone. */ |
| __unregister_trace_kprobe(tk); |
| ret = __register_trace_kprobe(tk); |
| if (ret) |
| pr_warn("Failed to re-register probe %s on %s: %d\n", |
| trace_probe_name(&tk->tp), |
| module_name(mod), ret); |
| } |
| } |
| mutex_unlock(&event_mutex); |
| |
| return NOTIFY_DONE; |
| } |
| |
| static struct notifier_block trace_kprobe_module_nb = { |
| .notifier_call = trace_kprobe_module_callback, |
| .priority = 1 /* Invoked after kprobe module callback */ |
| }; |
| |
| static int __trace_kprobe_create(int argc, const char *argv[]) |
| { |
| /* |
| * Argument syntax: |
| * - Add kprobe: |
| * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] |
| * - Add kretprobe: |
| * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS] |
| * Or |
| * p:[GRP/]EVENT] [MOD:]KSYM[+0]%return [FETCHARGS] |
| * |
| * Fetch args: |
| * $retval : fetch return value |
| * $stack : fetch stack address |
| * $stackN : fetch Nth of stack (N:0-) |
| * $comm : fetch current task comm |
| * @ADDR : fetch memory at ADDR (ADDR should be in kernel) |
| * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol) |
| * %REG : fetch register REG |
| * Dereferencing memory fetch: |
| * +|-offs(ARG) : fetch memory at ARG +|- offs address. |
| * Alias name of args: |
| * NAME=FETCHARG : set NAME as alias of FETCHARG. |
| * Type of args: |
| * FETCHARG:TYPE : use TYPE instead of unsigned long. |
| */ |
| struct trace_kprobe *tk = NULL; |
| int i, len, ret = 0; |
| bool is_return = false; |
| char *symbol = NULL, *tmp = NULL; |
| const char *event = NULL, *group = KPROBE_EVENT_SYSTEM; |
| enum probe_print_type ptype; |
| int maxactive = 0; |
| long offset = 0; |
| void *addr = NULL; |
| char buf[MAX_EVENT_NAME_LEN]; |
| unsigned int flags = TPARG_FL_KERNEL; |
| |
| switch (argv[0][0]) { |
| case 'r': |
| is_return = true; |
| break; |
| case 'p': |
| break; |
| default: |
| return -ECANCELED; |
| } |
| if (argc < 2) |
| return -ECANCELED; |
| |
| trace_probe_log_init("trace_kprobe", argc, argv); |
| |
| event = strchr(&argv[0][1], ':'); |
| if (event) |
| event++; |
| |
| if (isdigit(argv[0][1])) { |
| if (!is_return) { |
| trace_probe_log_err(1, MAXACT_NO_KPROBE); |
| goto parse_error; |
| } |
| if (event) |
| len = event - &argv[0][1] - 1; |
| else |
| len = strlen(&argv[0][1]); |
| if (len > MAX_EVENT_NAME_LEN - 1) { |
| trace_probe_log_err(1, BAD_MAXACT); |
| goto parse_error; |
| } |
| memcpy(buf, &argv[0][1], len); |
| buf[len] = '\0'; |
| ret = kstrtouint(buf, 0, &maxactive); |
| if (ret || !maxactive) { |
| trace_probe_log_err(1, BAD_MAXACT); |
| goto parse_error; |
| } |
| /* kretprobes instances are iterated over via a list. The |
| * maximum should stay reasonable. |
| */ |
| if (maxactive > KRETPROBE_MAXACTIVE_MAX) { |
| trace_probe_log_err(1, MAXACT_TOO_BIG); |
| goto parse_error; |
| } |
| } |
| |
| /* try to parse an address. if that fails, try to read the |
| * input as a symbol. */ |
| if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) { |
| trace_probe_log_set_index(1); |
| /* Check whether uprobe event specified */ |
| if (strchr(argv[1], '/') && strchr(argv[1], ':')) { |
| ret = -ECANCELED; |
| goto error; |
| } |
| /* a symbol specified */ |
| symbol = kstrdup(argv[1], GFP_KERNEL); |
| if (!symbol) |
| return -ENOMEM; |
| |
| tmp = strchr(symbol, '%'); |
| if (tmp) { |
| if (!strcmp(tmp, "%return")) { |
| *tmp = '\0'; |
| is_return = true; |
| } else { |
| trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX); |
| goto parse_error; |
| } |
| } |
| |
| /* TODO: support .init module functions */ |
| ret = traceprobe_split_symbol_offset(symbol, &offset); |
| if (ret || offset < 0 || offset > UINT_MAX) { |
| trace_probe_log_err(0, BAD_PROBE_ADDR); |
| goto parse_error; |
| } |
| if (is_return) |
| flags |= TPARG_FL_RETURN; |
| ret = kprobe_on_func_entry(NULL, symbol, offset); |
| if (ret == 0) |
| flags |= TPARG_FL_FENTRY; |
| /* Defer the ENOENT case until register kprobe */ |
| if (ret == -EINVAL && is_return) { |
| trace_probe_log_err(0, BAD_RETPROBE); |
| goto parse_error; |
| } |
| } |
| |
| trace_probe_log_set_index(0); |
| if (event) { |
| ret = traceprobe_parse_event_name(&event, &group, buf, |
| event - argv[0]); |
| if (ret) |
| goto parse_error; |
| } else { |
| /* Make a new event name */ |
| if (symbol) |
| snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld", |
| is_return ? 'r' : 'p', symbol, offset); |
| else |
| snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p", |
| is_return ? 'r' : 'p', addr); |
| sanitize_event_name(buf); |
| event = buf; |
| } |
| |
| /* setup a probe */ |
| tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive, |
| argc - 2, is_return); |
| if (IS_ERR(tk)) { |
| ret = PTR_ERR(tk); |
| /* This must return -ENOMEM, else there is a bug */ |
| WARN_ON_ONCE(ret != -ENOMEM); |
| goto out; /* We know tk is not allocated */ |
| } |
| argc -= 2; argv += 2; |
| |
| /* parse arguments */ |
| for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { |
| trace_probe_log_set_index(i + 2); |
| ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], flags); |
| if (ret) |
| goto error; /* This can be -ENOMEM */ |
| } |
| |
| ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL; |
| ret = traceprobe_set_print_fmt(&tk->tp, ptype); |
| if (ret < 0) |
| goto error; |
| |
| ret = register_trace_kprobe(tk); |
| if (ret) { |
| trace_probe_log_set_index(1); |
| if (ret == -EILSEQ) |
| trace_probe_log_err(0, BAD_INSN_BNDRY); |
| else if (ret == -ENOENT) |
| trace_probe_log_err(0, BAD_PROBE_ADDR); |
| else if (ret != -ENOMEM && ret != -EEXIST) |
| trace_probe_log_err(0, FAIL_REG_PROBE); |
| goto error; |
| } |
| |
| out: |
| trace_probe_log_clear(); |
| kfree(symbol); |
| return ret; |
| |
| parse_error: |
| ret = -EINVAL; |
| error: |
| free_trace_kprobe(tk); |
| goto out; |
| } |
| |
| static int trace_kprobe_create(const char *raw_command) |
| { |
| return trace_probe_create(raw_command, __trace_kprobe_create); |
| } |
| |
| static int create_or_delete_trace_kprobe(const char *raw_command) |
| { |
| int ret; |
| |
| if (raw_command[0] == '-') |
| return dyn_event_release(raw_command, &trace_kprobe_ops); |
| |
| ret = trace_kprobe_create(raw_command); |
| return ret == -ECANCELED ? -EINVAL : ret; |
| } |
| |
| static int trace_kprobe_run_command(struct dynevent_cmd *cmd) |
| { |
| return create_or_delete_trace_kprobe(cmd->seq.buffer); |
| } |
| |
| /** |
| * kprobe_event_cmd_init - Initialize a kprobe event command object |
| * @cmd: A pointer to the dynevent_cmd struct representing the new event |
| * @buf: A pointer to the buffer used to build the command |
| * @maxlen: The length of the buffer passed in @buf |
| * |
| * Initialize a synthetic event command object. Use this before |
| * calling any of the other kprobe_event functions. |
| */ |
| void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen) |
| { |
| dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE, |
| trace_kprobe_run_command); |
| } |
| EXPORT_SYMBOL_GPL(kprobe_event_cmd_init); |
| |
| /** |
| * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list |
| * @cmd: A pointer to the dynevent_cmd struct representing the new event |
| * @name: The name of the kprobe event |
| * @loc: The location of the kprobe event |
| * @kretprobe: Is this a return probe? |
| * @args: Variable number of arg (pairs), one pair for each field |
| * |
| * NOTE: Users normally won't want to call this function directly, but |
| * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically |
| * adds a NULL to the end of the arg list. If this function is used |
| * directly, make sure the last arg in the variable arg list is NULL. |
| * |
| * Generate a kprobe event command to be executed by |
| * kprobe_event_gen_cmd_end(). This function can be used to generate the |
| * complete command or only the first part of it; in the latter case, |
| * kprobe_event_add_fields() can be used to add more fields following this. |
| * |
| * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This |
| * returns -EINVAL if @loc == NULL. |
| * |
| * Return: 0 if successful, error otherwise. |
| */ |
| int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe, |
| const char *name, const char *loc, ...) |
| { |
| char buf[MAX_EVENT_NAME_LEN]; |
| struct dynevent_arg arg; |
| va_list args; |
| int ret; |
| |
| if (cmd->type != DYNEVENT_TYPE_KPROBE) |
| return -EINVAL; |
| |
| if (!loc) |
| return -EINVAL; |
| |
| if (kretprobe) |
| snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name); |
| else |
| snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name); |
| |
| ret = dynevent_str_add(cmd, buf); |
| if (ret) |
| return ret; |
| |
| dynevent_arg_init(&arg, 0); |
| arg.str = loc; |
| ret = dynevent_arg_add(cmd, &arg, NULL); |
| if (ret) |
| return ret; |
| |
| va_start(args, loc); |
| for (;;) { |
| const char *field; |
| |
| field = va_arg(args, const char *); |
| if (!field) |
| break; |
| |
| if (++cmd->n_fields > MAX_TRACE_ARGS) { |
| ret = -EINVAL; |
| break; |
| } |
| |
| arg.str = field; |
| ret = dynevent_arg_add(cmd, &arg, NULL); |
| if (ret) |
| break; |
| } |
| va_end(args); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start); |
| |
| /** |
| * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list |
| * @cmd: A pointer to the dynevent_cmd struct representing the new event |
| * @args: Variable number of arg (pairs), one pair for each field |
| * |
| * NOTE: Users normally won't want to call this function directly, but |
| * rather use the kprobe_event_add_fields() wrapper, which |
| * automatically adds a NULL to the end of the arg list. If this |
| * function is used directly, make sure the last arg in the variable |
| * arg list is NULL. |
| * |
| * Add probe fields to an existing kprobe command using a variable |
| * list of args. Fields are added in the same order they're listed. |
| * |
| * Return: 0 if successful, error otherwise. |
| */ |
| int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...) |
| { |
| struct dynevent_arg arg; |
| va_list args; |
| int ret = 0; |
| |
| if (cmd->type != DYNEVENT_TYPE_KPROBE) |
| return -EINVAL; |
| |
| dynevent_arg_init(&arg, 0); |
| |
| va_start(args, cmd); |
| for (;;) { |
| const char *field; |
| |
| field = va_arg(args, const char *); |
| if (!field) |
| break; |
| |
| if (++cmd->n_fields > MAX_TRACE_ARGS) { |
| ret = -EINVAL; |
| break; |
| } |
| |
| arg.str = field; |
| ret = dynevent_arg_add(cmd, &arg, NULL); |
| if (ret) |
| break; |
| } |
| va_end(args); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(__kprobe_event_add_fields); |
| |
| /** |
| * kprobe_event_delete - Delete a kprobe event |
| * @name: The name of the kprobe event to delete |
| * |
| * Delete a kprobe event with the give @name from kernel code rather |
| * than directly from the command line. |
| * |
| * Return: 0 if successful, error otherwise. |
| */ |
| int kprobe_event_delete(const char *name) |
| { |
| char buf[MAX_EVENT_NAME_LEN]; |
| |
| snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name); |
| |
| return create_or_delete_trace_kprobe(buf); |
| } |
| EXPORT_SYMBOL_GPL(kprobe_event_delete); |
| |
| static int trace_kprobe_release(struct dyn_event *ev) |
| { |
| struct trace_kprobe *tk = to_trace_kprobe(ev); |
| int ret = unregister_trace_kprobe(tk); |
| |
| if (!ret) |
| free_trace_kprobe(tk); |
| return ret; |
| } |
| |
| static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev) |
| { |
| struct trace_kprobe *tk = to_trace_kprobe(ev); |
| int i; |
| |
| seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p'); |
| if (trace_kprobe_is_return(tk) && tk->rp.maxactive) |
| seq_printf(m, "%d", tk->rp.maxactive); |
| seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp), |
| trace_probe_name(&tk->tp)); |
| |
| if (!tk->symbol) |
| seq_printf(m, " 0x%p", tk->rp.kp.addr); |
| else if (tk->rp.kp.offset) |
| seq_printf(m, " %s+%u", trace_kprobe_symbol(tk), |
| tk->rp.kp.offset); |
| else |
| seq_printf(m, " %s", trace_kprobe_symbol(tk)); |
| |
| for (i = 0; i < tk->tp.nr_args; i++) |
| seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm); |
| seq_putc(m, '\n'); |
| |
| return 0; |
| } |
| |
| static int probes_seq_show(struct seq_file *m, void *v) |
| { |
| struct dyn_event *ev = v; |
| |
| if (!is_trace_kprobe(ev)) |
| return 0; |
| |
| return trace_kprobe_show(m, ev); |
| } |
| |
| static const struct seq_operations probes_seq_op = { |
| .start = dyn_event_seq_start, |
| .next = dyn_event_seq_next, |
| .stop = dyn_event_seq_stop, |
| .show = probes_seq_show |
| }; |
| |
| static int probes_open(struct inode *inode, struct file *file) |
| { |
| int ret; |
| |
| ret = security_locked_down(LOCKDOWN_TRACEFS); |
| if (ret) |
| return ret; |
| |
| if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { |
| ret = dyn_events_release_all(&trace_kprobe_ops); |
| if (ret < 0) |
| return ret; |
| } |
| |
| return seq_open(file, &probes_seq_op); |
| } |
| |
| static ssize_t probes_write(struct file *file, const char __user *buffer, |
| size_t count, loff_t *ppos) |
| { |
| return trace_parse_run_command(file, buffer, count, ppos, |
| create_or_delete_trace_kprobe); |
| } |
| |
| static const struct file_operations kprobe_events_ops = { |
| .owner = THIS_MODULE, |
| .open = probes_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = seq_release, |
| .write = probes_write, |
| }; |
| |
| /* Probes profiling interfaces */ |
| static int probes_profile_seq_show(struct seq_file *m, void *v) |
| { |
| struct dyn_event *ev = v; |
| struct trace_kprobe *tk; |
| unsigned long nmissed; |
| |
| if (!is_trace_kprobe(ev)) |
| return 0; |
| |
| tk = to_trace_kprobe(ev); |
| nmissed = trace_kprobe_is_return(tk) ? |
| tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed; |
| seq_printf(m, " %-44s %15lu %15lu\n", |
| trace_probe_name(&tk->tp), |
| trace_kprobe_nhit(tk), |
| nmissed); |
| |
| return 0; |
| } |
| |
| static const struct seq_operations profile_seq_op = { |
| .start = dyn_event_seq_start, |
| .next = dyn_event_seq_next, |
| .stop = dyn_event_seq_stop, |
| .show = probes_profile_seq_show |
| }; |
| |
| static int profile_open(struct inode *inode, struct file *file) |
| { |
| int ret; |
| |
| ret = security_locked_down(LOCKDOWN_TRACEFS); |
| if (ret) |
| return ret; |
| |
| return seq_open(file, &profile_seq_op); |
| } |
| |
| static const struct file_operations kprobe_profile_ops = { |
| .owner = THIS_MODULE, |
| .open = profile_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = seq_release, |
| }; |
| |
| /* Kprobe specific fetch functions */ |
| |
| /* Return the length of string -- including null terminal byte */ |
| static nokprobe_inline int |
| fetch_store_strlen_user(unsigned long addr) |
| { |
| const void __user *uaddr = (__force const void __user *)addr; |
| |
| return strnlen_user_nofault(uaddr, MAX_STRING_SIZE); |
| } |
| |
| /* Return the length of string -- including null terminal byte */ |
| static nokprobe_inline int |
| fetch_store_strlen(unsigned long addr) |
| { |
| int ret, len = 0; |
| u8 c; |
| |
| #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE |
| if (addr < TASK_SIZE) |
| return fetch_store_strlen_user(addr); |
| #endif |
| |
| do { |
| ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1); |
| len++; |
| } while (c && ret == 0 && len < MAX_STRING_SIZE); |
| |
| return (ret < 0) ? ret : len; |
| } |
| |
| /* |
| * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf |
| * with max length and relative data location. |
| */ |
| static nokprobe_inline int |
| fetch_store_string_user(unsigned long addr, void *dest, void *base) |
| { |
| const void __user *uaddr = (__force const void __user *)addr; |
| int maxlen = get_loc_len(*(u32 *)dest); |
| void *__dest; |
| long ret; |
| |
| if (unlikely(!maxlen)) |
| return -ENOMEM; |
| |
| __dest = get_loc_data(dest, base); |
| |
| ret = strncpy_from_user_nofault(__dest, uaddr, maxlen); |
| if (ret >= 0) |
| *(u32 *)dest = make_data_loc(ret, __dest - base); |
| |
| return ret; |
| } |
| |
| /* |
| * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max |
| * length and relative data location. |
| */ |
| static nokprobe_inline int |
| fetch_store_string(unsigned long addr, void *dest, void *base) |
| { |
| int maxlen = get_loc_len(*(u32 *)dest); |
| void *__dest; |
| long ret; |
| |
| #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE |
| if ((unsigned long)addr < TASK_SIZE) |
| return fetch_store_string_user(addr, dest, base); |
| #endif |
| |
| if (unlikely(!maxlen)) |
| return -ENOMEM; |
| |
| __dest = get_loc_data(dest, base); |
| |
| /* |
| * Try to get string again, since the string can be changed while |
| * probing. |
| */ |
| ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen); |
| if (ret >= 0) |
| *(u32 *)dest = make_data_loc(ret, __dest - base); |
| |
| return ret; |
| } |
| |
| static nokprobe_inline int |
| probe_mem_read_user(void *dest, void *src, size_t size) |
| { |
| const void __user *uaddr = (__force const void __user *)src; |
| |
| return copy_from_user_nofault(dest, uaddr, size); |
| } |
| |
| static nokprobe_inline int |
| probe_mem_read(void *dest, void *src, size_t size) |
| { |
| #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE |
| if ((unsigned long)src < TASK_SIZE) |
| return probe_mem_read_user(dest, src, size); |
| #endif |
| return copy_from_kernel_nofault(dest, src, size); |
| } |
| |
| /* Note that we don't verify it, since the code does not come from user space */ |
| static int |
| process_fetch_insn(struct fetch_insn *code, void *rec, void *dest, |
| void *base) |
| { |
| struct pt_regs *regs = rec; |
| unsigned long val; |
| |
| retry: |
| /* 1st stage: get value from context */ |
| switch (code->op) { |
| case FETCH_OP_REG: |
| val = regs_get_register(regs, code->param); |
| break; |
| case FETCH_OP_STACK: |
| val = regs_get_kernel_stack_nth(regs, code->param); |
| break; |
| case FETCH_OP_STACKP: |
| val = kernel_stack_pointer(regs); |
| break; |
| case FETCH_OP_RETVAL: |
| val = regs_return_value(regs); |
| break; |
| case FETCH_OP_IMM: |
| val = code->immediate; |
| break; |
| case FETCH_OP_COMM: |
| val = (unsigned long)current->comm; |
| break; |
| case FETCH_OP_DATA: |
| val = (unsigned long)code->data; |
| break; |
| #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API |
| case FETCH_OP_ARG: |
| val = regs_get_kernel_argument(regs, code->param); |
| break; |
| #endif |
| case FETCH_NOP_SYMBOL: /* Ignore a place holder */ |
| code++; |
| goto retry; |
| default: |
| return -EILSEQ; |
| } |
| code++; |
| |
| return process_fetch_insn_bottom(code, val, dest, base); |
| } |
| NOKPROBE_SYMBOL(process_fetch_insn) |
| |
| /* Kprobe handler */ |
| static nokprobe_inline void |
| __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, |
| struct trace_event_file *trace_file) |
| { |
| struct kprobe_trace_entry_head *entry; |
| struct trace_event_call *call = trace_probe_event_call(&tk->tp); |
| struct trace_event_buffer fbuffer; |
| int dsize; |
| |
| WARN_ON(call != trace_file->event_call); |
| |
| if (trace_trigger_soft_disabled(trace_file)) |
| return; |
| |
| dsize = __get_data_size(&tk->tp, regs); |
| |
| entry = trace_event_buffer_reserve(&fbuffer, trace_file, |
| sizeof(*entry) + tk->tp.size + dsize); |
| if (!entry) |
| return; |
| |
| fbuffer.regs = regs; |
| entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event); |
| entry->ip = (unsigned long)tk->rp.kp.addr; |
| store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); |
| |
| trace_event_buffer_commit(&fbuffer); |
| } |
| |
| static void |
| kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs) |
| { |
| struct event_file_link *link; |
| |
| trace_probe_for_each_link_rcu(link, &tk->tp) |
| __kprobe_trace_func(tk, regs, link->file); |
| } |
| NOKPROBE_SYMBOL(kprobe_trace_func); |
| |
| /* Kretprobe handler */ |
| static nokprobe_inline void |
| __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, |
| struct pt_regs *regs, |
| struct trace_event_file *trace_file) |
| { |
| struct kretprobe_trace_entry_head *entry; |
| struct trace_event_buffer fbuffer; |
| struct trace_event_call *call = trace_probe_event_call(&tk->tp); |
| int dsize; |
| |
| WARN_ON(call != trace_file->event_call); |
| |
| if (trace_trigger_soft_disabled(trace_file)) |
| return; |
| |
| dsize = __get_data_size(&tk->tp, regs); |
| |
| entry = trace_event_buffer_reserve(&fbuffer, trace_file, |
| sizeof(*entry) + tk->tp.size + dsize); |
| if (!entry) |
| return; |
| |
| fbuffer.regs = regs; |
| entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event); |
| entry->func = (unsigned long)tk->rp.kp.addr; |
| entry->ret_ip = get_kretprobe_retaddr(ri); |
| store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); |
| |
| trace_event_buffer_commit(&fbuffer); |
| } |
| |
| static void |
| kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, |
| struct pt_regs *regs) |
| { |
| struct event_file_link *link; |
| |
| trace_probe_for_each_link_rcu(link, &tk->tp) |
| __kretprobe_trace_func(tk, ri, regs, link->file); |
| } |
| NOKPROBE_SYMBOL(kretprobe_trace_func); |
| |
| /* Event entry printers */ |
| static enum print_line_t |
| print_kprobe_event(struct trace_iterator *iter, int flags, |
| struct trace_event *event) |
| { |
| struct kprobe_trace_entry_head *field; |
| struct trace_seq *s = &iter->seq; |
| struct trace_probe *tp; |
| |
| field = (struct kprobe_trace_entry_head *)iter->ent; |
| tp = trace_probe_primary_from_call( |
| container_of(event, struct trace_event_call, event)); |
| if (WARN_ON_ONCE(!tp)) |
| goto out; |
| |
| trace_seq_printf(s, "%s: (", trace_probe_name(tp)); |
| |
| if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) |
| goto out; |
| |
| trace_seq_putc(s, ')'); |
| |
| if (print_probe_args(s, tp->args, tp->nr_args, |
| (u8 *)&field[1], field) < 0) |
| goto out; |
| |
| trace_seq_putc(s, '\n'); |
| out: |
| return trace_handle_return(s); |
| } |
| |
| static enum print_line_t |
| print_kretprobe_event(struct trace_iterator *iter, int flags, |
| struct trace_event *event) |
| { |
| struct kretprobe_trace_entry_head *field; |
| struct trace_seq *s = &iter->seq; |
| struct trace_probe *tp; |
| |
| field = (struct kretprobe_trace_entry_head *)iter->ent; |
| tp = trace_probe_primary_from_call( |
| container_of(event, struct trace_event_call, event)); |
| if (WARN_ON_ONCE(!tp)) |
| goto out; |
| |
| trace_seq_printf(s, "%s: (", trace_probe_name(tp)); |
| |
| if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET)) |
| goto out; |
| |
| trace_seq_puts(s, " <- "); |
| |
| if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET)) |
| goto out; |
| |
| trace_seq_putc(s, ')'); |
| |
| if (print_probe_args(s, tp->args, tp->nr_args, |
| (u8 *)&field[1], field) < 0) |
| goto out; |
| |
| trace_seq_putc(s, '\n'); |
| |
| out: |
| return trace_handle_return(s); |
| } |
| |
| |
| static int kprobe_event_define_fields(struct trace_event_call *event_call) |
| { |
| int ret; |
| struct kprobe_trace_entry_head field; |
| struct trace_probe *tp; |
| |
| tp = trace_probe_primary_from_call(event_call); |
| if (WARN_ON_ONCE(!tp)) |
| return -ENOENT; |
| |
| DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); |
| |
| return traceprobe_define_arg_fields(event_call, sizeof(field), tp); |
| } |
| |
| static int kretprobe_event_define_fields(struct trace_event_call *event_call) |
| { |
| int ret; |
| struct kretprobe_trace_entry_head field; |
| struct trace_probe *tp; |
| |
| tp = trace_probe_primary_from_call(event_call); |
| if (WARN_ON_ONCE(!tp)) |
| return -ENOENT; |
| |
| DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0); |
| DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0); |
| |
| return traceprobe_define_arg_fields(event_call, sizeof(field), tp); |
| } |
| |
| #ifdef CONFIG_PERF_EVENTS |
| |
| /* Kprobe profile handler */ |
| static int |
| kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) |
| { |
| struct trace_event_call *call = trace_probe_event_call(&tk->tp); |
| struct kprobe_trace_entry_head *entry; |
| struct hlist_head *head; |
| int size, __size, dsize; |
| int rctx; |
| |
| if (bpf_prog_array_valid(call)) { |
| unsigned long orig_ip = instruction_pointer(regs); |
| int ret; |
| |
| ret = trace_call_bpf(call, regs); |
| |
| /* |
| * We need to check and see if we modified the pc of the |
| * pt_regs, and if so return 1 so that we don't do the |
| * single stepping. |
| */ |
| if (orig_ip != instruction_pointer(regs)) |
| return 1; |
| if (!ret) |
| return 0; |
| } |
| |
| head = this_cpu_ptr(call->perf_events); |
| if (hlist_empty(head)) |
| return 0; |
| |
| dsize = __get_data_size(&tk->tp, regs); |
| __size = sizeof(*entry) + tk->tp.size + dsize; |
| size = ALIGN(__size + sizeof(u32), sizeof(u64)); |
| size -= sizeof(u32); |
| |
| entry = perf_trace_buf_alloc(size, NULL, &rctx); |
| if (!entry) |
| return 0; |
| |
| entry->ip = (unsigned long)tk->rp.kp.addr; |
| memset(&entry[1], 0, dsize); |
| store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); |
| perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, |
| head, NULL); |
| return 0; |
| } |
| NOKPROBE_SYMBOL(kprobe_perf_func); |
| |
| /* Kretprobe profile handler */ |
| static void |
| kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, |
| struct pt_regs *regs) |
| { |
| struct trace_event_call *call = trace_probe_event_call(&tk->tp); |
| struct kretprobe_trace_entry_head *entry; |
| struct hlist_head *head; |
| int size, __size, dsize; |
| int rctx; |
| |
| if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) |
| return; |
| |
| head = this_cpu_ptr(call->perf_events); |
| if (hlist_empty(head)) |
| return; |
| |
| dsize = __get_data_size(&tk->tp, regs); |
| __size = sizeof(*entry) + tk->tp.size + dsize; |
| size = ALIGN(__size + sizeof(u32), sizeof(u64)); |
| size -= sizeof(u32); |
| |
| entry = perf_trace_buf_alloc(size, NULL, &rctx); |
| if (!entry) |
| return; |
| |
| entry->func = (unsigned long)tk->rp.kp.addr; |
| entry->ret_ip = get_kretprobe_retaddr(ri); |
| store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); |
| perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, |
| head, NULL); |
| } |
| NOKPROBE_SYMBOL(kretprobe_perf_func); |
| |
| int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type, |
| const char **symbol, u64 *probe_offset, |
| u64 *probe_addr, bool perf_type_tracepoint) |
| { |
| const char *pevent = trace_event_name(event->tp_event); |
| const char *group = event->tp_event->class->system; |
| struct trace_kprobe *tk; |
| |
| if (perf_type_tracepoint) |
| tk = find_trace_kprobe(pevent, group); |
| else |
| tk = trace_kprobe_primary_from_call(event->tp_event); |
| if (!tk) |
| return -EINVAL; |
| |
| *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE |
| : BPF_FD_TYPE_KPROBE; |
| if (tk->symbol) { |
| *symbol = tk->symbol; |
| *probe_offset = tk->rp.kp.offset; |
| *probe_addr = 0; |
| } else { |
| *symbol = NULL; |
| *probe_offset = 0; |
| *probe_addr = (unsigned long)tk->rp.kp.addr; |
| } |
| return 0; |
| } |
| #endif /* CONFIG_PERF_EVENTS */ |
| |
| /* |
| * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex. |
| * |
| * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe |
| * lockless, but we can't race with this __init function. |
| */ |
| static int kprobe_register(struct trace_event_call *event, |
| enum trace_reg type, void *data) |
| { |
| struct trace_event_file *file = data; |
| |
| switch (type) { |
| case TRACE_REG_REGISTER: |
| return enable_trace_kprobe(event, file); |
| case TRACE_REG_UNREGISTER: |
| return disable_trace_kprobe(event, file); |
| |
| #ifdef CONFIG_PERF_EVENTS |
| case TRACE_REG_PERF_REGISTER: |
| return enable_trace_kprobe(event, NULL); |
| case TRACE_REG_PERF_UNREGISTER: |
| return disable_trace_kprobe(event, NULL); |
| case TRACE_REG_PERF_OPEN: |
| case TRACE_REG_PERF_CLOSE: |
| case TRACE_REG_PERF_ADD: |
| case TRACE_REG_PERF_DEL: |
| return 0; |
| #endif |
| } |
| return 0; |
| } |
| |
| static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) |
| { |
| struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp); |
| int ret = 0; |
| |
| raw_cpu_inc(*tk->nhit); |
| |
| if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) |
| kprobe_trace_func(tk, regs); |
| #ifdef CONFIG_PERF_EVENTS |
| if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) |
| ret = kprobe_perf_func(tk, regs); |
| #endif |
| return ret; |
| } |
| NOKPROBE_SYMBOL(kprobe_dispatcher); |
| |
| static int |
| kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) |
| { |
| struct kretprobe *rp = get_kretprobe(ri); |
| struct trace_kprobe *tk = container_of(rp, struct trace_kprobe, rp); |
| |
| raw_cpu_inc(*tk->nhit); |
| |
| if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) |
| kretprobe_trace_func(tk, ri, regs); |
| #ifdef CONFIG_PERF_EVENTS |
| if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) |
| kretprobe_perf_func(tk, ri, regs); |
| #endif |
| return 0; /* We don't tweak kernel, so just return 0 */ |
| } |
| NOKPROBE_SYMBOL(kretprobe_dispatcher); |
| |
| static struct trace_event_functions kretprobe_funcs = { |
| .trace = print_kretprobe_event |
| }; |
| |
| static struct trace_event_functions kprobe_funcs = { |
| .trace = print_kprobe_event |
| }; |
| |
| static struct trace_event_fields kretprobe_fields_array[] = { |
| { .type = TRACE_FUNCTION_TYPE, |
| .define_fields = kretprobe_event_define_fields }, |
| {} |
| }; |
| |
| static struct trace_event_fields kprobe_fields_array[] = { |
| { .type = TRACE_FUNCTION_TYPE, |
| .define_fields = kprobe_event_define_fields }, |
| {} |
| }; |
| |
| static inline void init_trace_event_call(struct trace_kprobe *tk) |
| { |
| struct trace_event_call *call = trace_probe_event_call(&tk->tp); |
| |
| if (trace_kprobe_is_return(tk)) { |
| call->event.funcs = &kretprobe_funcs; |
| call->class->fields_array = kretprobe_fields_array; |
| } else { |
| call->event.funcs = &kprobe_funcs; |
| call->class->fields_array = kprobe_fields_array; |
| } |
| |
| call->flags = TRACE_EVENT_FL_KPROBE; |
| call->class->reg = kprobe_register; |
| } |
| |
| static int register_kprobe_event(struct trace_kprobe *tk) |
| { |
| init_trace_event_call(tk); |
| |
| return trace_probe_register_event_call(&tk->tp); |
| } |
| |
| static int unregister_kprobe_event(struct trace_kprobe *tk) |
| { |
| return trace_probe_unregister_event_call(&tk->tp); |
| } |
| |
| #ifdef CONFIG_PERF_EVENTS |
| /* create a trace_kprobe, but don't add it to global lists */ |
| struct trace_event_call * |
| create_local_trace_kprobe(char *func, void *addr, unsigned long offs, |
| bool is_return) |
| { |
| enum probe_print_type ptype; |
| struct trace_kprobe *tk; |
| int ret; |
| char *event; |
| |
| /* |
| * local trace_kprobes are not added to dyn_event, so they are never |
| * searched in find_trace_kprobe(). Therefore, there is no concern of |
| * duplicated name here. |
| */ |
| event = func ? func : "DUMMY_EVENT"; |
| |
| tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func, |
| offs, 0 /* maxactive */, 0 /* nargs */, |
| is_return); |
| |
| if (IS_ERR(tk)) { |
| pr_info("Failed to allocate trace_probe.(%d)\n", |
| (int)PTR_ERR(tk)); |
| return ERR_CAST(tk); |
| } |
| |
| init_trace_event_call(tk); |
| |
| ptype = trace_kprobe_is_return(tk) ? |
| PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL; |
| if (traceprobe_set_print_fmt(&tk->tp, ptype) < 0) { |
| ret = -ENOMEM; |
| goto error; |
| } |
| |
| ret = __register_trace_kprobe(tk); |
| if (ret < 0) |
| goto error; |
| |
| return trace_probe_event_call(&tk->tp); |
| error: |
| free_trace_kprobe(tk); |
| return ERR_PTR(ret); |
| } |
| |
| void destroy_local_trace_kprobe(struct trace_event_call *event_call) |
| { |
| struct trace_kprobe *tk; |
| |
| tk = trace_kprobe_primary_from_call(event_call); |
| if (unlikely(!tk)) |
| return; |
| |
| if (trace_probe_is_enabled(&tk->tp)) { |
| WARN_ON(1); |
| return; |
| } |
| |
| __unregister_trace_kprobe(tk); |
| |
| free_trace_kprobe(tk); |
| } |
| #endif /* CONFIG_PERF_EVENTS */ |
| |
| static __init void enable_boot_kprobe_events(void) |
| { |
| struct trace_array *tr = top_trace_array(); |
| struct trace_event_file *file; |
| struct trace_kprobe *tk; |
| struct dyn_event *pos; |
| |
| mutex_lock(&event_mutex); |
| for_each_trace_kprobe(tk, pos) { |
| list_for_each_entry(file, &tr->events, list) |
| if (file->event_call == trace_probe_event_call(&tk->tp)) |
| trace_event_enable_disable(file, 1, 0); |
| } |
| mutex_unlock(&event_mutex); |
| } |
| |
| static __init void setup_boot_kprobe_events(void) |
| { |
| char *p, *cmd = kprobe_boot_events_buf; |
| int ret; |
| |
| strreplace(kprobe_boot_events_buf, ',', ' '); |
| |
| while (cmd && *cmd != '\0') { |
| p = strchr(cmd, ';'); |
| if (p) |
| *p++ = '\0'; |
| |
| ret = create_or_delete_trace_kprobe(cmd); |
| if (ret) |
| pr_warn("Failed to add event(%d): %s\n", ret, cmd); |
| |
| cmd = p; |
| } |
| |
| enable_boot_kprobe_events(); |
| } |
| |
| /* |
| * Register dynevent at core_initcall. This allows kernel to setup kprobe |
| * events in postcore_initcall without tracefs. |
| */ |
| static __init int init_kprobe_trace_early(void) |
| { |
| int ret; |
| |
| ret = dyn_event_register(&trace_kprobe_ops); |
| if (ret) |
| return ret; |
| |
| if (register_module_notifier(&trace_kprobe_module_nb)) |
| return -EINVAL; |
| |
| return 0; |
| } |
| core_initcall(init_kprobe_trace_early); |
| |
| /* Make a tracefs interface for controlling probe points */ |
| static __init int init_kprobe_trace(void) |
| { |
| int ret; |
| |
| ret = tracing_init_dentry(); |
| if (ret) |
| return 0; |
| |
| /* Event list interface */ |
| trace_create_file("kprobe_events", TRACE_MODE_WRITE, |
| NULL, NULL, &kprobe_events_ops); |
| |
| /* Profile interface */ |
| trace_create_file("kprobe_profile", TRACE_MODE_READ, |
| NULL, NULL, &kprobe_profile_ops); |
| |
| setup_boot_kprobe_events(); |
| |
| return 0; |
| } |
| fs_initcall(init_kprobe_trace); |
| |
| |
| #ifdef CONFIG_FTRACE_STARTUP_TEST |
| static __init struct trace_event_file * |
| find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr) |
| { |
| struct trace_event_file *file; |
| |
| list_for_each_entry(file, &tr->events, list) |
| if (file->event_call == trace_probe_event_call(&tk->tp)) |
| return file; |
| |
| return NULL; |
| } |
| |
| /* |
| * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this |
| * stage, we can do this lockless. |
| */ |
| static __init int kprobe_trace_self_tests_init(void) |
| { |
| int ret, warn = 0; |
| int (*target)(int, int, int, int, int, int); |
| struct trace_kprobe *tk; |
| struct trace_event_file *file; |
| |
| if (tracing_is_disabled()) |
| return -ENODEV; |
| |
| if (tracing_selftest_disabled) |
| return 0; |
| |
| target = kprobe_trace_selftest_target; |
| |
| pr_info("Testing kprobe tracing: "); |
| |
| ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)"); |
| if (WARN_ON_ONCE(ret)) { |
| pr_warn("error on probing function entry.\n"); |
| warn++; |
| } else { |
| /* Enable trace point */ |
| tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); |
| if (WARN_ON_ONCE(tk == NULL)) { |
| pr_warn("error on getting new probe.\n"); |
| warn++; |
| } else { |
| file = find_trace_probe_file(tk, top_trace_array()); |
| if (WARN_ON_ONCE(file == NULL)) { |
| pr_warn("error on getting probe file.\n"); |
| warn++; |
| } else |
| enable_trace_kprobe( |
| trace_probe_event_call(&tk->tp), file); |
| } |
| } |
| |
| ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval"); |
| if (WARN_ON_ONCE(ret)) { |
| pr_warn("error on probing function return.\n"); |
| warn++; |
| } else { |
| /* Enable trace point */ |
| tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); |
| if (WARN_ON_ONCE(tk == NULL)) { |
| pr_warn("error on getting 2nd new probe.\n"); |
| warn++; |
| } else { |
| file = find_trace_probe_file(tk, top_trace_array()); |
| if (WARN_ON_ONCE(file == NULL)) { |
| pr_warn("error on getting probe file.\n"); |
| warn++; |
| } else |
| enable_trace_kprobe( |
| trace_probe_event_call(&tk->tp), file); |
| } |
| } |
| |
| if (warn) |
| goto end; |
| |
| ret = target(1, 2, 3, 4, 5, 6); |
| |
| /* |
| * Not expecting an error here, the check is only to prevent the |
| * optimizer from removing the call to target() as otherwise there |
| * are no side-effects and the call is never performed. |
| */ |
| if (ret != 21) |
| warn++; |
| |
| /* Disable trace points before removing it */ |
| tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); |
| if (WARN_ON_ONCE(tk == NULL)) { |
| pr_warn("error on getting test probe.\n"); |
| warn++; |
| } else { |
| if (trace_kprobe_nhit(tk) != 1) { |
| pr_warn("incorrect number of testprobe hits\n"); |
| warn++; |
| } |
| |
| file = find_trace_probe_file(tk, top_trace_array()); |
| if (WARN_ON_ONCE(file == NULL)) { |
| pr_warn("error on getting probe file.\n"); |
| warn++; |
| } else |
| disable_trace_kprobe( |
| trace_probe_event_call(&tk->tp), file); |
| } |
| |
| tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); |
| if (WARN_ON_ONCE(tk == NULL)) { |
| pr_warn("error on getting 2nd test probe.\n"); |
| warn++; |
| } else { |
| if (trace_kprobe_nhit(tk) != 1) { |
| pr_warn("incorrect number of testprobe2 hits\n"); |
| warn++; |
| } |
| |
| file = find_trace_probe_file(tk, top_trace_array()); |
| if (WARN_ON_ONCE(file == NULL)) { |
| pr_warn("error on getting probe file.\n"); |
| warn++; |
| } else |
| disable_trace_kprobe( |
| trace_probe_event_call(&tk->tp), file); |
| } |
| |
| ret = create_or_delete_trace_kprobe("-:testprobe"); |
| if (WARN_ON_ONCE(ret)) { |
| pr_warn("error on deleting a probe.\n"); |
| warn++; |
| } |
| |
| ret = create_or_delete_trace_kprobe("-:testprobe2"); |
| if (WARN_ON_ONCE(ret)) { |
| pr_warn("error on deleting a probe.\n"); |
| warn++; |
| } |
| |
| end: |
| ret = dyn_events_release_all(&trace_kprobe_ops); |
| if (WARN_ON_ONCE(ret)) { |
| pr_warn("error on cleaning up probes.\n"); |
| warn++; |
| } |
| /* |
| * Wait for the optimizer work to finish. Otherwise it might fiddle |
| * with probes in already freed __init text. |
| */ |
| wait_for_kprobe_optimizer(); |
| if (warn) |
| pr_cont("NG: Some tests are failed. Please check them.\n"); |
| else |
| pr_cont("OK\n"); |
| return 0; |
| } |
| |
| late_initcall(kprobe_trace_self_tests_init); |
| |
| #endif |