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- // 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/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(int argc, const char **argv);
- 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)))
- #define SIZEOF_TRACE_KPROBE(n) \
- (offsetof(struct trace_kprobe, tp.args) + \
- (sizeof(struct probe_arg) * (n)))
- 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';
- mutex_lock(&module_mutex);
- ret = !!find_module(tk->symbol);
- mutex_unlock(&module_mutex);
- *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(SIZEOF_TRACE_KPROBE(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_probe *pos;
- struct trace_kprobe *tk;
- list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
- tk = container_of(pos, struct trace_kprobe, tp);
- 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 *pos, *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(pos, trace_probe_probe_list(tp), list) {
- tk = container_of(pos, struct trace_kprobe, tp);
- 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;
- /* 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;
- struct trace_probe *pos;
- int i;
- list_for_each_entry(pos, &tpe->probes, list) {
- orig = container_of(pos, struct trace_kprobe, tp);
- 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);
- 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);
- 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 */
- };
- /* Convert certain expected symbols into '_' when generating event names */
- static inline void sanitize_event_name(char *name)
- {
- while (*name++ != '\0')
- if (*name == ':' || *name == '.')
- *name = '_';
- }
- 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;
- 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++) {
- tmp = kstrdup(argv[i], GFP_KERNEL);
- if (!tmp) {
- ret = -ENOMEM;
- goto error;
- }
- trace_probe_log_set_index(i + 2);
- ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
- kfree(tmp);
- if (ret)
- goto error; /* This can be -ENOMEM */
- }
- ret = traceprobe_set_print_fmt(&tk->tp, is_return);
- 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 create_or_delete_trace_kprobe(int argc, char **argv)
- {
- int ret;
- if (argv[0][0] == '-')
- return dyn_event_release(argc, argv, &trace_kprobe_ops);
- ret = trace_kprobe_create(argc, (const char **)argv);
- return ret == -ECANCELED ? -EINVAL : ret;
- }
- static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
- {
- return trace_run_command(cmd->seq.buffer, create_or_delete_trace_kprobe);
- }
- /**
- * 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 trace_run_command(buf, create_or_delete_trace_kprobe);
- }
- 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, struct pt_regs *regs, void *dest,
- void *base)
- {
- 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;
- local_save_flags(fbuffer.flags);
- fbuffer.pc = preempt_count();
- fbuffer.trace_file = trace_file;
- dsize = __get_data_size(&tk->tp, regs);
- fbuffer.event =
- trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
- call->event.type,
- sizeof(*entry) + tk->tp.size + dsize,
- fbuffer.flags, fbuffer.pc);
- if (!fbuffer.event)
- 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;
- local_save_flags(fbuffer.flags);
- fbuffer.pc = preempt_count();
- fbuffer.trace_file = trace_file;
- dsize = __get_data_size(&tk->tp, regs);
- fbuffer.event =
- trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
- call->event.type,
- sizeof(*entry) + tk->tp.size + dsize,
- fbuffer.flags, fbuffer.pc);
- if (!fbuffer.event)
- return;
- fbuffer.regs = regs;
- entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
- entry->func = (unsigned long)tk->rp.kp.addr;
- entry->ret_ip = (unsigned long)ri->ret_addr;
- 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 = (unsigned long)ri->ret_addr;
- 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 trace_kprobe *tk = container_of(ri->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 tweek 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)
- {
- 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);
- if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 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 = trace_run_command(cmd, create_or_delete_trace_kprobe);
- 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;
- struct dentry *entry;
- ret = tracing_init_dentry();
- if (ret)
- return 0;
- entry = tracefs_create_file("kprobe_events", 0644, NULL,
- NULL, &kprobe_events_ops);
- /* Event list interface */
- if (!entry)
- pr_warn("Could not create tracefs 'kprobe_events' entry\n");
- /* Profile interface */
- entry = tracefs_create_file("kprobe_profile", 0444, NULL,
- NULL, &kprobe_profile_ops);
- if (!entry)
- pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
- 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 = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
- create_or_delete_trace_kprobe);
- 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 = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
- create_or_delete_trace_kprobe);
- 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 = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
- if (WARN_ON_ONCE(ret)) {
- pr_warn("error on deleting a probe.\n");
- warn++;
- }
- ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
- 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
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