/* * Kprobes-based tracing events * * Created by Masami Hiramatsu <mhiramat@redhat.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include <linux/module.h> #include <linux/uaccess.h> #include "trace_probe.h" #define KPROBE_EVENT_SYSTEM "kprobes" /** * Kprobe event core functions */ struct trace_kprobe { struct list_head list; struct kretprobe rp; /* Use rp.kp for kprobe use */ unsigned long __percpu *nhit; const char *symbol; /* symbol name */ struct trace_probe tp; }; #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_is_on_module(struct trace_kprobe *tk) { return !!strchr(trace_kprobe_symbol(tk), ':'); } 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 int register_kprobe_event(struct trace_kprobe *tk); static int unregister_kprobe_event(struct trace_kprobe *tk); static DEFINE_MUTEX(probe_lock); static LIST_HEAD(probe_list); static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs); static int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs); /* Memory fetching by symbol */ struct symbol_cache { char *symbol; long offset; unsigned long addr; }; unsigned long update_symbol_cache(struct symbol_cache *sc) { sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol); if (sc->addr) sc->addr += sc->offset; return sc->addr; } void free_symbol_cache(struct symbol_cache *sc) { kfree(sc->symbol); kfree(sc); } struct symbol_cache *alloc_symbol_cache(const char *sym, long offset) { struct symbol_cache *sc; if (!sym || strlen(sym) == 0) return NULL; sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL); if (!sc) return NULL; sc->symbol = kstrdup(sym, GFP_KERNEL); if (!sc->symbol) { kfree(sc); return NULL; } sc->offset = offset; update_symbol_cache(sc); return sc; } /* * Kprobes-specific fetch functions */ #define DEFINE_FETCH_stack(type) \ static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \ void *offset, void *dest) \ { \ *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \ (unsigned int)((unsigned long)offset)); \ } \ NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type)); DEFINE_BASIC_FETCH_FUNCS(stack) /* No string on the stack entry */ #define fetch_stack_string NULL #define fetch_stack_string_size NULL #define DEFINE_FETCH_memory(type) \ static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \ void *addr, void *dest) \ { \ type retval; \ if (probe_kernel_address(addr, retval)) \ *(type *)dest = 0; \ else \ *(type *)dest = retval; \ } \ NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type)); DEFINE_BASIC_FETCH_FUNCS(memory) /* * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max * length and relative data location. */ static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs, void *addr, void *dest) { int maxlen = get_rloc_len(*(u32 *)dest); u8 *dst = get_rloc_data(dest); long ret; if (!maxlen) return; /* * Try to get string again, since the string can be changed while * probing. */ ret = strncpy_from_unsafe(dst, addr, maxlen); if (ret < 0) { /* Failed to fetch string */ dst[0] = '\0'; *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest)); } else { *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest)); } } NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string)); /* Return the length of string -- including null terminal byte */ static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs, void *addr, void *dest) { mm_segment_t old_fs; int ret, len = 0; u8 c; old_fs = get_fs(); set_fs(KERNEL_DS); pagefault_disable(); do { ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1); len++; } while (c && ret == 0 && len < MAX_STRING_SIZE); pagefault_enable(); set_fs(old_fs); if (ret < 0) /* Failed to check the length */ *(u32 *)dest = 0; else *(u32 *)dest = len; } NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size)); #define DEFINE_FETCH_symbol(type) \ void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\ { \ struct symbol_cache *sc = data; \ if (sc->addr) \ fetch_memory_##type(regs, (void *)sc->addr, dest); \ else \ *(type *)dest = 0; \ } \ NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type)); DEFINE_BASIC_FETCH_FUNCS(symbol) DEFINE_FETCH_symbol(string) DEFINE_FETCH_symbol(string_size) /* kprobes don't support file_offset fetch methods */ #define fetch_file_offset_u8 NULL #define fetch_file_offset_u16 NULL #define fetch_file_offset_u32 NULL #define fetch_file_offset_u64 NULL #define fetch_file_offset_string NULL #define fetch_file_offset_string_size NULL /* Fetch type information table */ static const struct fetch_type kprobes_fetch_type_table[] = { /* Special types */ [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, "__data_loc char[]"), [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32, string_size, sizeof(u32), 0, "u32"), /* Basic types */ ASSIGN_FETCH_TYPE(u8, u8, 0), ASSIGN_FETCH_TYPE(u16, u16, 0), ASSIGN_FETCH_TYPE(u32, u32, 0), ASSIGN_FETCH_TYPE(u64, u64, 0), ASSIGN_FETCH_TYPE(s8, u8, 1), ASSIGN_FETCH_TYPE(s16, u16, 1), ASSIGN_FETCH_TYPE(s32, u32, 1), ASSIGN_FETCH_TYPE(s64, u64, 1), ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0), ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0), ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0), ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0), ASSIGN_FETCH_TYPE_END }; /* * 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 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; 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; INIT_LIST_HEAD(&tk->list); 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; 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 trace_kprobe *tk; list_for_each_entry(tk, &probe_list, list) if (strcmp(trace_event_name(&tk->tp.call), event) == 0 && strcmp(tk->tp.call.class->system, group) == 0) return tk; return NULL; } /* * 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) { int ret = 0; if (file) { struct event_file_link *link; 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; } else tk->tp.flags |= TP_FLAG_PROFILE; 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); } 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; } 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_sched(); kfree(link); /* Ignored if link == NULL */ } return ret; } /* 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; for (i = 0; i < tk->tp.nr_args; i++) traceprobe_update_arg(&tk->tp.args[i]); /* 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 { pr_warn("Could not insert probe at %s+%lu: %d\n", trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret); if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) { pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); ret = 0; } 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: call with locking probe_lock */ 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); list_del(&tk->list); 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(&probe_lock); /* 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 < 0) unregister_kprobe_event(tk); else list_add_tail(&tk->list, &probe_list); end: mutex_unlock(&probe_lock); 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 trace_kprobe *tk; int ret; if (val != MODULE_STATE_COMING) return NOTIFY_DONE; /* Update probes on coming module */ mutex_lock(&probe_lock); list_for_each_entry(tk, &probe_list, list) { 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(&probe_lock); return NOTIFY_DONE; } static struct notifier_block trace_kprobe_module_nb = { .notifier_call = trace_kprobe_module_callback, .priority = 1 /* Invoked after kprobe module callback */ }; static int create_trace_kprobe(int argc, char **argv) { /* * Argument syntax: * - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] * - Add kretprobe: r[:[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, ret = 0; bool is_return = false, is_delete = false; char *symbol = NULL, *event = NULL, *group = NULL; char *arg; unsigned long offset = 0; void *addr = NULL; char buf[MAX_EVENT_NAME_LEN]; /* argc must be >= 1 */ if (argv[0][0] == 'p') is_return = false; else if (argv[0][0] == 'r') is_return = true; else if (argv[0][0] == '-') is_delete = true; else { pr_info("Probe definition must be started with 'p', 'r' or" " '-'.\n"); return -EINVAL; } if (argv[0][1] == ':') { event = &argv[0][2]; if (strchr(event, '/')) { group = event; event = strchr(group, '/') + 1; event[-1] = '\0'; if (strlen(group) == 0) { pr_info("Group name is not specified\n"); return -EINVAL; } } if (strlen(event) == 0) { pr_info("Event name is not specified\n"); return -EINVAL; } } if (!group) group = KPROBE_EVENT_SYSTEM; if (is_delete) { if (!event) { pr_info("Delete command needs an event name.\n"); return -EINVAL; } mutex_lock(&probe_lock); tk = find_trace_kprobe(event, group); if (!tk) { mutex_unlock(&probe_lock); pr_info("Event %s/%s doesn't exist.\n", group, event); return -ENOENT; } /* delete an event */ ret = unregister_trace_kprobe(tk); if (ret == 0) free_trace_kprobe(tk); mutex_unlock(&probe_lock); return ret; } if (argc < 2) { pr_info("Probe point is not specified.\n"); return -EINVAL; } if (isdigit(argv[1][0])) { if (is_return) { pr_info("Return probe point must be a symbol.\n"); return -EINVAL; } /* an address specified */ ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr); if (ret) { pr_info("Failed to parse address.\n"); return ret; } } else { /* a symbol specified */ symbol = argv[1]; /* TODO: support .init module functions */ ret = traceprobe_split_symbol_offset(symbol, &offset); if (ret) { pr_info("Failed to parse symbol.\n"); return ret; } if (offset && is_return) { pr_info("Return probe must be used without offset.\n"); return -EINVAL; } } argc -= 2; argv += 2; /* setup a probe */ if (!event) { /* Make a new event name */ if (symbol) snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld", is_return ? 'r' : 'p', symbol, offset); else snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p", is_return ? 'r' : 'p', addr); event = buf; } tk = alloc_trace_kprobe(group, event, addr, symbol, offset, argc, is_return); if (IS_ERR(tk)) { pr_info("Failed to allocate trace_probe.(%d)\n", (int)PTR_ERR(tk)); return PTR_ERR(tk); } /* parse arguments */ ret = 0; for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { struct probe_arg *parg = &tk->tp.args[i]; /* Increment count for freeing args in error case */ tk->tp.nr_args++; /* Parse argument name */ arg = strchr(argv[i], '='); if (arg) { *arg++ = '\0'; parg->name = kstrdup(argv[i], GFP_KERNEL); } else { arg = argv[i]; /* If argument name is omitted, set "argN" */ snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1); parg->name = kstrdup(buf, GFP_KERNEL); } if (!parg->name) { pr_info("Failed to allocate argument[%d] name.\n", i); ret = -ENOMEM; goto error; } if (!is_good_name(parg->name)) { pr_info("Invalid argument[%d] name: %s\n", i, parg->name); ret = -EINVAL; goto error; } if (traceprobe_conflict_field_name(parg->name, tk->tp.args, i)) { pr_info("Argument[%d] name '%s' conflicts with " "another field.\n", i, argv[i]); ret = -EINVAL; goto error; } /* Parse fetch argument */ ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg, is_return, true, kprobes_fetch_type_table); if (ret) { pr_info("Parse error at argument[%d]. (%d)\n", i, ret); goto error; } } ret = register_trace_kprobe(tk); if (ret) goto error; return 0; error: free_trace_kprobe(tk); return ret; } static int release_all_trace_kprobes(void) { struct trace_kprobe *tk; int ret = 0; mutex_lock(&probe_lock); /* Ensure no probe is in use. */ list_for_each_entry(tk, &probe_list, list) if (trace_probe_is_enabled(&tk->tp)) { ret = -EBUSY; goto end; } /* TODO: Use batch unregistration */ while (!list_empty(&probe_list)) { tk = list_entry(probe_list.next, struct trace_kprobe, list); ret = unregister_trace_kprobe(tk); if (ret) goto end; free_trace_kprobe(tk); } end: mutex_unlock(&probe_lock); return ret; } /* Probes listing interfaces */ static void *probes_seq_start(struct seq_file *m, loff_t *pos) { mutex_lock(&probe_lock); return seq_list_start(&probe_list, *pos); } static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos) { return seq_list_next(v, &probe_list, pos); } static void probes_seq_stop(struct seq_file *m, void *v) { mutex_unlock(&probe_lock); } static int probes_seq_show(struct seq_file *m, void *v) { struct trace_kprobe *tk = v; 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 const struct seq_operations probes_seq_op = { .start = probes_seq_start, .next = probes_seq_next, .stop = probes_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 = release_all_trace_kprobes(); 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 traceprobe_probes_write(file, buffer, count, ppos, create_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 trace_kprobe *tk = v; 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 = probes_seq_start, .next = probes_seq_next, .stop = probes_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 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(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], 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(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], 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; u8 *data; int i; 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, ')'); data = (u8 *)&field[1]; for (i = 0; i < tp->nr_args; i++) if (!tp->args[i].type->print(s, tp->args[i].name, data + tp->args[i].offset, field)) 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; u8 *data; int i; 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, ')'); data = (u8 *)&field[1]; for (i = 0; i < tp->nr_args; i++) if (!tp->args[i].type->print(s, tp->args[i].name, data + tp->args[i].offset, field)) 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, i; 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); /* Set argument names as fields */ for (i = 0; i < tk->tp.nr_args; i++) { struct probe_arg *parg = &tk->tp.args[i]; ret = trace_define_field(event_call, parg->type->fmttype, parg->name, sizeof(field) + parg->offset, parg->type->size, parg->type->is_signed, FILTER_OTHER); if (ret) return ret; } return 0; } static int kretprobe_event_define_fields(struct trace_event_call *event_call) { int ret, i; 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); /* Set argument names as fields */ for (i = 0; i < tk->tp.nr_args; i++) { struct probe_arg *parg = &tk->tp.args[i]; ret = trace_define_field(event_call, parg->type->fmttype, parg->name, sizeof(field) + parg->offset, parg->type->size, parg->type->is_signed, FILTER_OTHER); if (ret) return ret; } return 0; } #ifdef CONFIG_PERF_EVENTS /* Kprobe profile handler */ static void kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) { struct trace_event_call *call = &tk->tp.call; struct bpf_prog *prog = call->prog; struct kprobe_trace_entry_head *entry; struct hlist_head *head; int size, __size, dsize; int rctx; if (prog && !trace_call_bpf(prog, 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->ip = (unsigned long)tk->rp.kp.addr; memset(&entry[1], 0, dsize); store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, head, NULL); } 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 bpf_prog *prog = call->prog; struct kretprobe_trace_entry_head *entry; struct hlist_head *head; int size, __size, dsize; int rctx; if (prog && !trace_call_bpf(prog, 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(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, head, NULL); } NOKPROBE_SYMBOL(kretprobe_perf_func); #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); 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) kprobe_perf_func(tk, regs); #endif return 0; /* We don't tweek kernel, so just return 0 */ } 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 int register_kprobe_event(struct trace_kprobe *tk) { struct trace_event_call *call = &tk->tp.call; int ret; /* Initialize trace_event_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; } if (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; } call->flags = TRACE_EVENT_FL_KPROBE; call->class->reg = kprobe_register; call->data = tk; 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; } /* Make a tracefs interface for controlling probe points */ static __init int init_kprobe_trace(void) { struct dentry *d_tracer; struct dentry *entry; 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 /* * The "__used" keeps gcc from removing the function symbol * from the kallsyms table. 'noinline' makes sure that there * isn't an inlined version used by the test method below */ static __used __init noinline int kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6) { return a1 + a2 + a3 + a4 + a5 + a6; } static struct __init 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 = traceprobe_command("p:testprobe kprobe_trace_selftest_target " "$stack $stack0 +0($stack)", create_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 = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target " "$retval", create_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 = traceprobe_command("-:testprobe", create_trace_kprobe); if (WARN_ON_ONCE(ret)) { pr_warn("error on deleting a probe.\n"); warn++; } ret = traceprobe_command("-:testprobe2", create_trace_kprobe); if (WARN_ON_ONCE(ret)) { pr_warn("error on deleting a probe.\n"); warn++; } end: release_all_trace_kprobes(); 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