| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Masami Hiramatsu | 5396 | 71.07% | 58 | 44.96% |
| Srikar Dronamraju | 420 | 5.53% | 2 | 1.55% |
| Namhyung Kim | 335 | 4.41% | 3 | 2.33% |
| Song Liu | 297 | 3.91% | 1 | 0.78% |
| Steven Rostedt | 293 | 3.86% | 19 | 14.73% |
| Yonghong Song | 177 | 2.33% | 2 | 1.55% |
| Josef Bacik | 103 | 1.36% | 2 | 1.55% |
| Marcin Nowakowski | 90 | 1.19% | 2 | 1.55% |
| Oleg Nesterov | 83 | 1.09% | 3 | 2.33% |
| Jiri Olsa | 43 | 0.57% | 3 | 2.33% |
| Martin KaFai Lau | 43 | 0.57% | 1 | 0.78% |
| Alban Crequy | 41 | 0.54% | 1 | 0.78% |
| Lai Jiangshan | 36 | 0.47% | 2 | 1.55% |
| Alexei Starovoitov | 30 | 0.40% | 2 | 1.55% |
| Xiao Guangrong | 29 | 0.38% | 2 | 1.55% |
| Frédéric Weisbecker | 26 | 0.34% | 4 | 3.10% |
| Peter Zijlstra | 22 | 0.29% | 5 | 3.88% |
| Artem Savkov | 21 | 0.28% | 1 | 0.78% |
| Tom Zanussi | 20 | 0.26% | 2 | 1.55% |
| Andrea Righi | 14 | 0.18% | 1 | 0.78% |
| Mathieu Desnoyers | 13 | 0.17% | 1 | 0.78% |
| Arnd Bergmann | 12 | 0.16% | 1 | 0.78% |
| Li Zefan | 10 | 0.13% | 2 | 1.55% |
| Yoshihiro Yunomae | 9 | 0.12% | 1 | 0.78% |
| Rasmus Villemoes | 8 | 0.11% | 1 | 0.78% |
| Joe Perches | 5 | 0.07% | 1 | 0.78% |
| Andrey Vagin | 4 | 0.05% | 1 | 0.78% |
| Thomas Gleixner | 4 | 0.05% | 1 | 0.78% |
| Francis Deslauriers | 3 | 0.04% | 1 | 0.78% |
| Ingo Molnar | 3 | 0.04% | 1 | 0.78% |
| Changbin Du | 1 | 0.01% | 1 | 0.78% |
| Paul E. McKenney | 1 | 0.01% | 1 | 0.78% |
| Total | 7592 | 129 |
// 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/module.h> #include <linux/uaccess.h> #include <linux/rculist.h> #include <linux/error-injection.h> #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 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, 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(mod->name); const char *name = trace_kprobe_symbol(tk); return strncmp(mod->name, 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(const char *system, const char *event, struct dyn_event *ev) { struct trace_kprobe *tk = to_trace_kprobe(ev); return strcmp(trace_event_name(&tk->tp.call), event) == 0 && (!system || strcmp(tk->tp.call.class->system, system) == 0); } 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; } /* 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; } bool trace_kprobe_on_func_entry(struct trace_event_call *call) { struct trace_kprobe *tk = (struct trace_kprobe *)call->data; return 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); } bool trace_kprobe_error_injectable(struct trace_event_call *call) { struct trace_kprobe *tk = (struct trace_kprobe *)call->data; return within_error_injection_list(trace_kprobe_address(tk)); } 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); /* * 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; if (!event || !is_good_name(event)) { ret = -EINVAL; goto error; } tk->tp.call.class = &tk->tp.class; tk->tp.call.name = kstrdup(event, GFP_KERNEL); if (!tk->tp.call.name) goto error; if (!group || !is_good_name(group)) { ret = -EINVAL; goto error; } tk->tp.class.system = kstrdup(group, GFP_KERNEL); if (!tk->tp.class.system) goto error; dyn_event_init(&tk->devent, &trace_kprobe_ops); INIT_LIST_HEAD(&tk->tp.files); return tk; error: kfree(tk->tp.call.name); kfree(tk->symbol); free_percpu(tk->nhit); kfree(tk); return ERR_PTR(ret); } static void free_trace_kprobe(struct trace_kprobe *tk) { int i; if (!tk) return; for (i = 0; i < tk->tp.nr_args; i++) traceprobe_free_probe_arg(&tk->tp.args[i]); kfree(tk->tp.call.class->system); kfree(tk->tp.call.name); kfree(tk->symbol); free_percpu(tk->nhit); kfree(tk); } 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_event_name(&tk->tp.call), event) == 0 && strcmp(tk->tp.call.class->system, group) == 0) return tk; return NULL; } static inline int __enable_trace_kprobe(struct trace_kprobe *tk) { int ret = 0; if (trace_probe_is_registered(&tk->tp) && !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; } /* * Enable trace_probe * if the file is NULL, enable "perf" handler, or enable "trace" handler. */ static int enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file) { struct event_file_link *link; int ret = 0; if (file) { link = kmalloc(sizeof(*link), GFP_KERNEL); if (!link) { ret = -ENOMEM; goto out; } link->file = file; list_add_tail_rcu(&link->list, &tk->tp.files); tk->tp.flags |= TP_FLAG_TRACE; ret = __enable_trace_kprobe(tk); if (ret) { list_del_rcu(&link->list); kfree(link); tk->tp.flags &= ~TP_FLAG_TRACE; } } else { tk->tp.flags |= TP_FLAG_PROFILE; ret = __enable_trace_kprobe(tk); if (ret) tk->tp.flags &= ~TP_FLAG_PROFILE; } out: return ret; } /* * Disable trace_probe * if the file is NULL, disable "perf" handler, or disable "trace" handler. */ static int disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file) { struct event_file_link *link = NULL; int wait = 0; int ret = 0; if (file) { link = find_event_file_link(&tk->tp, file); if (!link) { ret = -EINVAL; goto out; } list_del_rcu(&link->list); wait = 1; if (!list_empty(&tk->tp.files)) goto out; tk->tp.flags &= ~TP_FLAG_TRACE; } else tk->tp.flags &= ~TP_FLAG_PROFILE; if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) { if (trace_kprobe_is_return(tk)) disable_kretprobe(&tk->rp); else disable_kprobe(&tk->rp.kp); wait = 1; } /* * if tk is not added to any list, it must be a local trace_kprobe * created with perf_event_open. We don't need to wait for these * trace_kprobes */ if (list_empty(&tk->devent.list)) wait = 0; out: if (wait) { /* * Synchronize with kprobe_trace_func/kretprobe_trace_func * to ensure disabled (all running handlers are finished). * This is not only for kfree(), but also the caller, * trace_remove_event_call() supposes it for releasing * event_call related objects, which will be accessed in * the kprobe_trace_func/kretprobe_trace_func. */ synchronize_rcu(); kfree(link); /* Ignored if link == NULL */ } return ret; } #if defined(CONFIG_KPROBES_ON_FTRACE) && \ !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE) static bool within_notrace_func(struct trace_kprobe *tk) { unsigned long offset, size, addr; addr = trace_kprobe_address(tk); 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); } #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; if (trace_probe_is_registered(&tk->tp)) 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); if (ret == 0) { tk->tp.flags |= TP_FLAG_REGISTERED; } else if (ret == -EILSEQ) { pr_warn("Probing address(0x%p) is not an instruction boundary.\n", tk->rp.kp.addr); ret = -EINVAL; } return ret; } /* Internal unregister function - just handle k*probes and flags */ static void __unregister_trace_kprobe(struct trace_kprobe *tk) { if (trace_probe_is_registered(&tk->tp)) { if (trace_kprobe_is_return(tk)) unregister_kretprobe(&tk->rp); else unregister_kprobe(&tk->rp.kp); tk->tp.flags &= ~TP_FLAG_REGISTERED; /* Cleanup kprobe for reuse */ 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) { /* 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; __unregister_trace_kprobe(tk); dyn_event_remove(&tk->devent); return 0; } /* 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); /* Delete old (same name) event if exist */ old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call), tk->tp.call.class->system); if (old_tk) { ret = unregister_trace_kprobe(old_tk); if (ret < 0) goto end; free_trace_kprobe(old_tk); } /* Register new event */ ret = register_kprobe_event(tk); if (ret) { 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_event_name(&tk->tp.call), mod->name, 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] * 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; 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; flags |= TPARG_FL_RETURN; break; case 'p': break; default: return -ECANCELED; } if (argc < 2) return -ECANCELED; event = strchr(&argv[0][1], ':'); if (event) event++; if (is_return && isdigit(argv[0][1])) { if (event) len = event - &argv[0][1] - 1; else len = strlen(&argv[0][1]); if (len > MAX_EVENT_NAME_LEN - 1) return -E2BIG; memcpy(buf, &argv[0][1], len); buf[len] = '\0'; ret = kstrtouint(buf, 0, &maxactive); if (ret) { pr_info("Failed to parse maxactive.\n"); return ret; } /* kretprobes instances are iterated over via a list. The * maximum should stay reasonable. */ if (maxactive > KRETPROBE_MAXACTIVE_MAX) { pr_info("Maxactive is too big (%d > %d).\n", maxactive, KRETPROBE_MAXACTIVE_MAX); return -E2BIG; } } /* try to parse an address. if that fails, try to read the * input as a symbol. */ if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) { /* Check whether uprobe event specified */ if (strchr(argv[1], '/') && strchr(argv[1], ':')) return -ECANCELED; /* a symbol specified */ symbol = kstrdup(argv[1], GFP_KERNEL); if (!symbol) return -ENOMEM; /* TODO: support .init module functions */ ret = traceprobe_split_symbol_offset(symbol, &offset); if (ret || offset < 0 || offset > UINT_MAX) { pr_info("Failed to parse either an address or a symbol.\n"); goto out; } if (kprobe_on_func_entry(NULL, symbol, offset)) flags |= TPARG_FL_FENTRY; if (offset && is_return && !(flags & TPARG_FL_FENTRY)) { pr_info("Given offset is not valid for return probe.\n"); ret = -EINVAL; goto out; } } argc -= 2; argv += 2; if (event) { ret = traceprobe_parse_event_name(&event, &group, buf); if (ret) goto out; } 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, is_return); if (IS_ERR(tk)) { pr_info("Failed to allocate trace_probe.(%d)\n", (int)PTR_ERR(tk)); ret = PTR_ERR(tk); goto out; } /* parse arguments */ for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { tmp = kstrdup(argv[i], GFP_KERNEL); if (!tmp) { ret = -ENOMEM; goto error; } ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags); kfree(tmp); if (ret) goto error; } ret = register_trace_kprobe(tk); if (ret) goto error; out: kfree(symbol); return ret; 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_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'); seq_printf(m, ":%s/%s", tk->tp.call.class->system, trace_event_name(&tk->tp.call)); 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; 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; if (!is_trace_kprobe(ev)) return 0; tk = to_trace_kprobe(ev); seq_printf(m, " %-44s %15lu %15lu\n", trace_event_name(&tk->tp.call), trace_kprobe_nhit(tk), tk->rp.kp.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) { 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(unsigned long addr) { int ret, len = 0; u8 c; do { ret = probe_mem_read(&c, (u8 *)addr + len, 1); len++; } while (c && ret == 0 && len < MAX_STRING_SIZE); return (ret < 0) ? ret : len; } /* * 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); u8 *dst = get_loc_data(dest, base); long ret; if (unlikely(!maxlen)) return -ENOMEM; /* * Try to get string again, since the string can be changed while * probing. */ ret = strncpy_from_unsafe(dst, (void *)addr, maxlen); if (ret >= 0) *(u32 *)dest = make_data_loc(ret, (void *)dst - base); return ret; } static nokprobe_inline int probe_mem_read(void *dest, void *src, size_t size) { return probe_kernel_read(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; #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 ring_buffer_event *event; struct ring_buffer *buffer; int size, dsize, pc; unsigned long irq_flags; struct trace_event_call *call = &tk->tp.call; WARN_ON(call != trace_file->event_call); if (trace_trigger_soft_disabled(trace_file)) return; local_save_flags(irq_flags); pc = preempt_count(); dsize = __get_data_size(&tk->tp, regs); size = sizeof(*entry) + tk->tp.size + dsize; event = trace_event_buffer_lock_reserve(&buffer, trace_file, call->event.type, size, irq_flags, pc); if (!event) return; entry = ring_buffer_event_data(event); entry->ip = (unsigned long)tk->rp.kp.addr; store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); event_trigger_unlock_commit_regs(trace_file, buffer, event, entry, irq_flags, pc, regs); } static void kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs) { struct event_file_link *link; list_for_each_entry_rcu(link, &tk->tp.files, list) __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 ring_buffer_event *event; struct ring_buffer *buffer; int size, pc, dsize; unsigned long irq_flags; struct trace_event_call *call = &tk->tp.call; WARN_ON(call != trace_file->event_call); if (trace_trigger_soft_disabled(trace_file)) return; local_save_flags(irq_flags); pc = preempt_count(); dsize = __get_data_size(&tk->tp, regs); size = sizeof(*entry) + tk->tp.size + dsize; event = trace_event_buffer_lock_reserve(&buffer, trace_file, call->event.type, size, irq_flags, pc); if (!event) return; entry = ring_buffer_event_data(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); event_trigger_unlock_commit_regs(trace_file, buffer, event, entry, irq_flags, pc, regs); } static void kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, struct pt_regs *regs) { struct event_file_link *link; list_for_each_entry_rcu(link, &tk->tp.files, list) __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 = container_of(event, struct trace_probe, call.event); trace_seq_printf(s, "%s: (", trace_event_name(&tp->call)); 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 = container_of(event, struct trace_probe, call.event); trace_seq_printf(s, "%s: (", trace_event_name(&tp->call)); 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_kprobe *tk = (struct trace_kprobe *)event_call->data; DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); return traceprobe_define_arg_fields(event_call, sizeof(field), &tk->tp); } static int kretprobe_event_define_fields(struct trace_event_call *event_call) { int ret; struct kretprobe_trace_entry_head field; struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data; 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), &tk->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 = &tk->tp.call; 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 = &tk->tp.call; 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 = event->tp_event->data; 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_kprobe *tk = (struct trace_kprobe *)event->data; struct trace_event_file *file = data; switch (type) { case TRACE_REG_REGISTER: return enable_trace_kprobe(tk, file); case TRACE_REG_UNREGISTER: return disable_trace_kprobe(tk, file); #ifdef CONFIG_PERF_EVENTS case TRACE_REG_PERF_REGISTER: return enable_trace_kprobe(tk, NULL); case TRACE_REG_PERF_UNREGISTER: return disable_trace_kprobe(tk, 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 (tk->tp.flags & TP_FLAG_TRACE) kprobe_trace_func(tk, regs); #ifdef CONFIG_PERF_EVENTS if (tk->tp.flags & 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 (tk->tp.flags & TP_FLAG_TRACE) kretprobe_trace_func(tk, ri, regs); #ifdef CONFIG_PERF_EVENTS if (tk->tp.flags & 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 inline void init_trace_event_call(struct trace_kprobe *tk, struct trace_event_call *call) { INIT_LIST_HEAD(&call->class->fields); if (trace_kprobe_is_return(tk)) { call->event.funcs = &kretprobe_funcs; call->class->define_fields = kretprobe_event_define_fields; } else { call->event.funcs = &kprobe_funcs; call->class->define_fields = kprobe_event_define_fields; } call->flags = TRACE_EVENT_FL_KPROBE; call->class->reg = kprobe_register; call->data = tk; } static int register_kprobe_event(struct trace_kprobe *tk) { struct trace_event_call *call = &tk->tp.call; int ret = 0; init_trace_event_call(tk, call); if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) return -ENOMEM; ret = register_trace_event(&call->event); if (!ret) { kfree(call->print_fmt); return -ENODEV; } ret = trace_add_event_call(call); if (ret) { pr_info("Failed to register kprobe event: %s\n", trace_event_name(call)); kfree(call->print_fmt); unregister_trace_event(&call->event); } return ret; } static int unregister_kprobe_event(struct trace_kprobe *tk) { int ret; /* tp->event is unregistered in trace_remove_event_call() */ ret = trace_remove_event_call(&tk->tp.call); if (!ret) kfree(tk->tp.call.print_fmt); return ret; } #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, &tk->tp.call); 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) { kfree(tk->tp.call.print_fmt); goto error; } return &tk->tp.call; 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 = container_of(event_call, struct trace_kprobe, tp.call); if (trace_probe_is_enabled(&tk->tp)) { WARN_ON(1); return; } __unregister_trace_kprobe(tk); kfree(tk->tp.call.print_fmt); free_trace_kprobe(tk); } #endif /* CONFIG_PERF_EVENTS */ /* Make a tracefs interface for controlling probe points */ static __init int init_kprobe_trace(void) { struct dentry *d_tracer; struct dentry *entry; int ret; ret = dyn_event_register(&trace_kprobe_ops); if (ret) return ret; if (register_module_notifier(&trace_kprobe_module_nb)) return -EINVAL; d_tracer = tracing_init_dentry(); if (IS_ERR(d_tracer)) return 0; entry = tracefs_create_file("kprobe_events", 0644, d_tracer, 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, d_tracer, NULL, &kprobe_profile_ops); if (!entry) pr_warn("Could not create tracefs 'kprobe_profile' entry\n"); 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 == &tk->tp.call) 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; 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(tk, 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(tk, 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(tk, 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(tk, 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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