diff options
Diffstat (limited to 'kernel/trace/trace_kprobe.c')
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 2133 |
1 files changed, 2133 insertions, 0 deletions
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c new file mode 100644 index 000000000..e3993d196 --- /dev/null +++ b/kernel/trace/trace_kprobe.c @@ -0,0 +1,2133 @@ +// 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" +#include "trace_probe_kernel.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 (event[0] == '\0' || + 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 count_symbols(void *data, unsigned long unused) +{ + unsigned int *count = data; + + (*count)++; + + return 0; +} + +struct sym_count_ctx { + unsigned int count; + const char *name; +}; + +static int count_mod_symbols(void *data, const char *name, + struct module *module, unsigned long unused) +{ + struct sym_count_ctx *ctx = data; + + if (strcmp(name, ctx->name) == 0) + ctx->count++; + + return 0; +} + +static unsigned int number_of_same_symbols(char *func_name) +{ + struct sym_count_ctx ctx = { .count = 0, .name = func_name }; + + kallsyms_on_each_match_symbol(count_symbols, func_name, &ctx.count); + + module_kallsyms_on_each_symbol(count_mod_symbols, &ctx); + + return ctx.count; +} + +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]; + char gbuf[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; + } + } + + if (symbol && !strchr(symbol, ':')) { + unsigned int count; + + count = number_of_same_symbols(symbol); + if (count > 1) { + /* + * Users should use ADDR to remove the ambiguity of + * using KSYM only. + */ + trace_probe_log_err(0, NON_UNIQ_SYMBOL); + ret = -EADDRNOTAVAIL; + + goto error; + } else if (count == 0) { + /* + * We can return ENOENT earlier than when register the + * kprobe. + */ + trace_probe_log_err(0, BAD_PROBE_ADDR); + ret = -ENOENT; + + goto error; + } + } + + trace_probe_log_set_index(0); + if (event) { + ret = traceprobe_parse_event_name(&event, &group, gbuf, + event - argv[0]); + if (ret) + goto parse_error; + } + + if (!event) { + /* 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 + * @kretprobe: Is this a return probe? + * @name: The name of the kprobe event + * @loc: The location of the kprobe event + * @...: 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 + * @...: 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) +{ + return kern_fetch_store_strlen_user(addr); +} + +/* Return the length of string -- including null terminal byte */ +static nokprobe_inline int +fetch_store_strlen(unsigned long addr) +{ + return kern_fetch_store_strlen(addr); +} + +/* + * 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) +{ + return kern_fetch_store_string_user(addr, dest, base); +} + +/* + * 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) +{ + return kern_fetch_store_string(addr, dest, base); +} + +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; + + /* + * There is a small chance that get_kretprobe(ri) returns NULL when + * the kretprobe is unregister on another CPU between kretprobe's + * trampoline_handler and this function. + */ + if (unlikely(!rp)) + return 0; + + 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; + + if (func) { + unsigned int count; + + count = number_of_same_symbols(func); + if (count > 1) + /* + * Users should use addr to remove the ambiguity of + * using func only. + */ + return ERR_PTR(-EADDRNOTAVAIL); + else if (count == 0) + /* + * We can return ENOENT earlier than when register the + * kprobe. + */ + return ERR_PTR(-ENOENT); + } + + /* + * 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 |