/* * uprobes-based tracing events * * 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 * * Copyright (C) IBM Corporation, 2010-2012 * Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com> */ #include <linux/module.h> #include <linux/uaccess.h> #include <linux/uprobes.h> #include <linux/namei.h> #include <linux/string.h> #include "trace_probe.h" #define UPROBE_EVENT_SYSTEM "uprobes" struct uprobe_trace_entry_head { struct trace_entry ent; unsigned long vaddr[]; }; #define SIZEOF_TRACE_ENTRY(is_return) \ (sizeof(struct uprobe_trace_entry_head) + \ sizeof(unsigned long) * (is_return ? 2 : 1)) #define DATAOF_TRACE_ENTRY(entry, is_return) \ ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return)) struct trace_uprobe_filter { rwlock_t rwlock; int nr_systemwide; struct list_head perf_events; }; /* * uprobe event core functions */ struct trace_uprobe { struct list_head list; struct trace_uprobe_filter filter; struct uprobe_consumer consumer; struct inode *inode; char *filename; unsigned long offset; unsigned long nhit; struct trace_probe tp; }; #define SIZEOF_TRACE_UPROBE(n) \ (offsetof(struct trace_uprobe, tp.args) + \ (sizeof(struct probe_arg) * (n))) static int register_uprobe_event(struct trace_uprobe *tu); static int unregister_uprobe_event(struct trace_uprobe *tu); static DEFINE_MUTEX(uprobe_lock); static LIST_HEAD(uprobe_list); struct uprobe_dispatch_data { struct trace_uprobe *tu; unsigned long bp_addr; }; static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); static int uretprobe_dispatcher(struct uprobe_consumer *con, unsigned long func, struct pt_regs *regs); #ifdef CONFIG_STACK_GROWSUP static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) { return addr - (n * sizeof(long)); } #else static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) { return addr + (n * sizeof(long)); } #endif static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n) { unsigned long ret; unsigned long addr = user_stack_pointer(regs); addr = adjust_stack_addr(addr, n); if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret))) return 0; return ret; } /* * Uprobes-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)get_user_stack_nth(regs, \ ((unsigned long)offset)); \ } 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; \ void __user *vaddr = (void __force __user *) addr; \ \ if (copy_from_user(&retval, vaddr, sizeof(type))) \ *(type *)dest = 0; \ else \ *(type *) dest = retval; \ } 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) { long ret; u32 rloc = *(u32 *)dest; int maxlen = get_rloc_len(rloc); u8 *dst = get_rloc_data(dest); void __user *src = (void __force __user *) addr; if (!maxlen) return; ret = strncpy_from_user(dst, src, maxlen); if (ret < 0) { /* Failed to fetch string */ ((u8 *)get_rloc_data(dest))[0] = '\0'; *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc)); } else { *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc)); } } static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs, void *addr, void *dest) { int len; void __user *vaddr = (void __force __user *) addr; len = strnlen_user(vaddr, MAX_STRING_SIZE); if (len == 0 || len > MAX_STRING_SIZE) /* Failed to check length */ *(u32 *)dest = 0; else *(u32 *)dest = len; } static unsigned long translate_user_vaddr(void *file_offset) { unsigned long base_addr; struct uprobe_dispatch_data *udd; udd = (void *) current->utask->vaddr; base_addr = udd->bp_addr - udd->tu->offset; return base_addr + (unsigned long)file_offset; } #define DEFINE_FETCH_file_offset(type) \ static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs, \ void *offset, void *dest)\ { \ void *vaddr = (void *)translate_user_vaddr(offset); \ \ FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest); \ } DEFINE_BASIC_FETCH_FUNCS(file_offset) DEFINE_FETCH_file_offset(string) DEFINE_FETCH_file_offset(string_size) /* Fetch type information table */ static const struct fetch_type uprobes_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 }; static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter) { rwlock_init(&filter->rwlock); filter->nr_systemwide = 0; INIT_LIST_HEAD(&filter->perf_events); } static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter) { return !filter->nr_systemwide && list_empty(&filter->perf_events); } static inline bool is_ret_probe(struct trace_uprobe *tu) { return tu->consumer.ret_handler != NULL; } /* * Allocate new trace_uprobe and initialize it (including uprobes). */ static struct trace_uprobe * alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) { struct trace_uprobe *tu; if (!event || !is_good_name(event)) return ERR_PTR(-EINVAL); if (!group || !is_good_name(group)) return ERR_PTR(-EINVAL); tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL); if (!tu) return ERR_PTR(-ENOMEM); tu->tp.call.class = &tu->tp.class; tu->tp.call.name = kstrdup(event, GFP_KERNEL); if (!tu->tp.call.name) goto error; tu->tp.class.system = kstrdup(group, GFP_KERNEL); if (!tu->tp.class.system) goto error; INIT_LIST_HEAD(&tu->list); INIT_LIST_HEAD(&tu->tp.files); tu->consumer.handler = uprobe_dispatcher; if (is_ret) tu->consumer.ret_handler = uretprobe_dispatcher; init_trace_uprobe_filter(&tu->filter); return tu; error: kfree(tu->tp.call.name); kfree(tu); return ERR_PTR(-ENOMEM); } static void free_trace_uprobe(struct trace_uprobe *tu) { int i; for (i = 0; i < tu->tp.nr_args; i++) traceprobe_free_probe_arg(&tu->tp.args[i]); iput(tu->inode); kfree(tu->tp.call.class->system); kfree(tu->tp.call.name); kfree(tu->filename); kfree(tu); } static struct trace_uprobe *find_probe_event(const char *event, const char *group) { struct trace_uprobe *tu; list_for_each_entry(tu, &uprobe_list, list) if (strcmp(trace_event_name(&tu->tp.call), event) == 0 && strcmp(tu->tp.call.class->system, group) == 0) return tu; return NULL; } /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */ static int unregister_trace_uprobe(struct trace_uprobe *tu) { int ret; ret = unregister_uprobe_event(tu); if (ret) return ret; list_del(&tu->list); free_trace_uprobe(tu); return 0; } /* Register a trace_uprobe and probe_event */ static int register_trace_uprobe(struct trace_uprobe *tu) { struct trace_uprobe *old_tu; int ret; mutex_lock(&uprobe_lock); /* register as an event */ old_tu = find_probe_event(trace_event_name(&tu->tp.call), tu->tp.call.class->system); if (old_tu) { /* delete old event */ ret = unregister_trace_uprobe(old_tu); if (ret) goto end; } ret = register_uprobe_event(tu); if (ret) { pr_warn("Failed to register probe event(%d)\n", ret); goto end; } list_add_tail(&tu->list, &uprobe_list); end: mutex_unlock(&uprobe_lock); return ret; } /* * Argument syntax: * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] * * - Remove uprobe: -:[GRP/]EVENT */ static int create_trace_uprobe(int argc, char **argv) { struct trace_uprobe *tu; struct inode *inode; char *arg, *event, *group, *filename; char buf[MAX_EVENT_NAME_LEN]; struct path path; unsigned long offset; bool is_delete, is_return; int i, ret; inode = NULL; ret = 0; is_delete = false; is_return = false; event = NULL; group = NULL; /* argc must be >= 1 */ if (argv[0][0] == '-') is_delete = true; else if (argv[0][0] == 'r') is_return = true; else if (argv[0][0] != 'p') { pr_info("Probe definition must be started with 'p', 'r' or '-'.\n"); return -EINVAL; } if (argv[0][1] == ':') { event = &argv[0][2]; arg = strchr(event, '/'); if (arg) { group = event; event = arg + 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 = UPROBE_EVENT_SYSTEM; if (is_delete) { int ret; if (!event) { pr_info("Delete command needs an event name.\n"); return -EINVAL; } mutex_lock(&uprobe_lock); tu = find_probe_event(event, group); if (!tu) { mutex_unlock(&uprobe_lock); pr_info("Event %s/%s doesn't exist.\n", group, event); return -ENOENT; } /* delete an event */ ret = unregister_trace_uprobe(tu); mutex_unlock(&uprobe_lock); return ret; } if (argc < 2) { pr_info("Probe point is not specified.\n"); return -EINVAL; } arg = strchr(argv[1], ':'); if (!arg) { ret = -EINVAL; goto fail_address_parse; } *arg++ = '\0'; filename = argv[1]; ret = kern_path(filename, LOOKUP_FOLLOW, &path); if (ret) goto fail_address_parse; inode = igrab(d_inode(path.dentry)); path_put(&path); if (!inode || !S_ISREG(inode->i_mode)) { ret = -EINVAL; goto fail_address_parse; } ret = kstrtoul(arg, 0, &offset); if (ret) goto fail_address_parse; argc -= 2; argv += 2; /* setup a probe */ if (!event) { char *tail; char *ptr; tail = kstrdup(kbasename(filename), GFP_KERNEL); if (!tail) { ret = -ENOMEM; goto fail_address_parse; } ptr = strpbrk(tail, ".-_"); if (ptr) *ptr = '\0'; snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); event = buf; kfree(tail); } tu = alloc_trace_uprobe(group, event, argc, is_return); if (IS_ERR(tu)) { pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu)); ret = PTR_ERR(tu); goto fail_address_parse; } tu->offset = offset; tu->inode = inode; tu->filename = kstrdup(filename, GFP_KERNEL); if (!tu->filename) { pr_info("Failed to allocate filename.\n"); ret = -ENOMEM; goto error; } /* parse arguments */ ret = 0; for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { struct probe_arg *parg = &tu->tp.args[i]; /* Increment count for freeing args in error case */ tu->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, tu->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, &tu->tp.size, parg, is_return, false, uprobes_fetch_type_table); if (ret) { pr_info("Parse error at argument[%d]. (%d)\n", i, ret); goto error; } } ret = register_trace_uprobe(tu); if (ret) goto error; return 0; error: free_trace_uprobe(tu); return ret; fail_address_parse: iput(inode); pr_info("Failed to parse address or file.\n"); return ret; } static int cleanup_all_probes(void) { struct trace_uprobe *tu; int ret = 0; mutex_lock(&uprobe_lock); while (!list_empty(&uprobe_list)) { tu = list_entry(uprobe_list.next, struct trace_uprobe, list); ret = unregister_trace_uprobe(tu); if (ret) break; } mutex_unlock(&uprobe_lock); return ret; } /* Probes listing interfaces */ static void *probes_seq_start(struct seq_file *m, loff_t *pos) { mutex_lock(&uprobe_lock); return seq_list_start(&uprobe_list, *pos); } static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos) { return seq_list_next(v, &uprobe_list, pos); } static void probes_seq_stop(struct seq_file *m, void *v) { mutex_unlock(&uprobe_lock); } static int probes_seq_show(struct seq_file *m, void *v) { struct trace_uprobe *tu = v; char c = is_ret_probe(tu) ? 'r' : 'p'; int i; seq_printf(m, "%c:%s/%s", c, tu->tp.call.class->system, trace_event_name(&tu->tp.call)); seq_printf(m, " %s:", tu->filename); /* Don't print "0x (null)" when offset is 0 */ if (tu->offset) { seq_printf(m, "0x%p", (void *)tu->offset); } else { switch (sizeof(void *)) { case 4: seq_printf(m, "0x00000000"); break; case 8: default: seq_printf(m, "0x0000000000000000"); break; } } for (i = 0; i < tu->tp.nr_args; i++) seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->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 = cleanup_all_probes(); if (ret) 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_uprobe); } static const struct file_operations uprobe_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_uprobe *tu = v; seq_printf(m, " %s %-44s %15lu\n", tu->filename, trace_event_name(&tu->tp.call), tu->nhit); 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 uprobe_profile_ops = { .owner = THIS_MODULE, .open = profile_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, }; struct uprobe_cpu_buffer { struct mutex mutex; void *buf; }; static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer; static int uprobe_buffer_refcnt; static int uprobe_buffer_init(void) { int cpu, err_cpu; uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer); if (uprobe_cpu_buffer == NULL) return -ENOMEM; for_each_possible_cpu(cpu) { struct page *p = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL, 0); if (p == NULL) { err_cpu = cpu; goto err; } per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p); mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex); } return 0; err: for_each_possible_cpu(cpu) { if (cpu == err_cpu) break; free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf); } free_percpu(uprobe_cpu_buffer); return -ENOMEM; } static int uprobe_buffer_enable(void) { int ret = 0; BUG_ON(!mutex_is_locked(&event_mutex)); if (uprobe_buffer_refcnt++ == 0) { ret = uprobe_buffer_init(); if (ret < 0) uprobe_buffer_refcnt--; } return ret; } static void uprobe_buffer_disable(void) { int cpu; BUG_ON(!mutex_is_locked(&event_mutex)); if (--uprobe_buffer_refcnt == 0) { for_each_possible_cpu(cpu) free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf); free_percpu(uprobe_cpu_buffer); uprobe_cpu_buffer = NULL; } } static struct uprobe_cpu_buffer *uprobe_buffer_get(void) { struct uprobe_cpu_buffer *ucb; int cpu; cpu = raw_smp_processor_id(); ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu); /* * Use per-cpu buffers for fastest access, but we might migrate * so the mutex makes sure we have sole access to it. */ mutex_lock(&ucb->mutex); return ucb; } static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) { mutex_unlock(&ucb->mutex); } static void __uprobe_trace_func(struct trace_uprobe *tu, unsigned long func, struct pt_regs *regs, struct uprobe_cpu_buffer *ucb, int dsize, struct trace_event_file *trace_file) { struct uprobe_trace_entry_head *entry; struct ring_buffer_event *event; struct ring_buffer *buffer; void *data; int size, esize; struct trace_event_call *call = &tu->tp.call; WARN_ON(call != trace_file->event_call); if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE)) return; if (trace_trigger_soft_disabled(trace_file)) return; esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); size = esize + tu->tp.size + dsize; event = trace_event_buffer_lock_reserve(&buffer, trace_file, call->event.type, size, 0, 0); if (!event) return; entry = ring_buffer_event_data(event); if (is_ret_probe(tu)) { entry->vaddr[0] = func; entry->vaddr[1] = instruction_pointer(regs); data = DATAOF_TRACE_ENTRY(entry, true); } else { entry->vaddr[0] = instruction_pointer(regs); data = DATAOF_TRACE_ENTRY(entry, false); } memcpy(data, ucb->buf, tu->tp.size + dsize); event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0); } /* uprobe handler */ static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs, struct uprobe_cpu_buffer *ucb, int dsize) { struct event_file_link *link; if (is_ret_probe(tu)) return 0; rcu_read_lock(); list_for_each_entry_rcu(link, &tu->tp.files, list) __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file); rcu_read_unlock(); return 0; } static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, struct pt_regs *regs, struct uprobe_cpu_buffer *ucb, int dsize) { struct event_file_link *link; rcu_read_lock(); list_for_each_entry_rcu(link, &tu->tp.files, list) __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file); rcu_read_unlock(); } /* Event entry printers */ static enum print_line_t print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) { struct uprobe_trace_entry_head *entry; struct trace_seq *s = &iter->seq; struct trace_uprobe *tu; u8 *data; int i; entry = (struct uprobe_trace_entry_head *)iter->ent; tu = container_of(event, struct trace_uprobe, tp.call.event); if (is_ret_probe(tu)) { trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", trace_event_name(&tu->tp.call), entry->vaddr[1], entry->vaddr[0]); data = DATAOF_TRACE_ENTRY(entry, true); } else { trace_seq_printf(s, "%s: (0x%lx)", trace_event_name(&tu->tp.call), entry->vaddr[0]); data = DATAOF_TRACE_ENTRY(entry, false); } for (i = 0; i < tu->tp.nr_args; i++) { struct probe_arg *parg = &tu->tp.args[i]; if (!parg->type->print(s, parg->name, data + parg->offset, entry)) goto out; } trace_seq_putc(s, '\n'); out: return trace_handle_return(s); } typedef bool (*filter_func_t)(struct uprobe_consumer *self, enum uprobe_filter_ctx ctx, struct mm_struct *mm); static int probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file, filter_func_t filter) { bool enabled = trace_probe_is_enabled(&tu->tp); struct event_file_link *link = NULL; int ret; if (file) { if (tu->tp.flags & TP_FLAG_PROFILE) return -EINTR; link = kmalloc(sizeof(*link), GFP_KERNEL); if (!link) return -ENOMEM; link->file = file; list_add_tail_rcu(&link->list, &tu->tp.files); tu->tp.flags |= TP_FLAG_TRACE; } else { if (tu->tp.flags & TP_FLAG_TRACE) return -EINTR; tu->tp.flags |= TP_FLAG_PROFILE; } WARN_ON(!uprobe_filter_is_empty(&tu->filter)); if (enabled) return 0; ret = uprobe_buffer_enable(); if (ret) goto err_flags; tu->consumer.filter = filter; ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); if (ret) goto err_buffer; return 0; err_buffer: uprobe_buffer_disable(); err_flags: if (file) { list_del(&link->list); kfree(link); tu->tp.flags &= ~TP_FLAG_TRACE; } else { tu->tp.flags &= ~TP_FLAG_PROFILE; } return ret; } static void probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file) { if (!trace_probe_is_enabled(&tu->tp)) return; if (file) { struct event_file_link *link; link = find_event_file_link(&tu->tp, file); if (!link) return; list_del_rcu(&link->list); /* synchronize with u{,ret}probe_trace_func */ synchronize_sched(); kfree(link); if (!list_empty(&tu->tp.files)) return; } WARN_ON(!uprobe_filter_is_empty(&tu->filter)); uprobe_unregister(tu->inode, tu->offset, &tu->consumer); tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE; uprobe_buffer_disable(); } static int uprobe_event_define_fields(struct trace_event_call *event_call) { int ret, i, size; struct uprobe_trace_entry_head field; struct trace_uprobe *tu = event_call->data; if (is_ret_probe(tu)) { DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0); DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0); size = SIZEOF_TRACE_ENTRY(true); } else { DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); size = SIZEOF_TRACE_ENTRY(false); } /* Set argument names as fields */ for (i = 0; i < tu->tp.nr_args; i++) { struct probe_arg *parg = &tu->tp.args[i]; ret = trace_define_field(event_call, parg->type->fmttype, parg->name, size + parg->offset, parg->type->size, parg->type->is_signed, FILTER_OTHER); if (ret) return ret; } return 0; } #ifdef CONFIG_PERF_EVENTS static bool __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) { struct perf_event *event; if (filter->nr_systemwide) return true; list_for_each_entry(event, &filter->perf_events, hw.tp_list) { if (event->hw.target->mm == mm) return true; } return false; } static inline bool uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event) { return __uprobe_perf_filter(&tu->filter, event->hw.target->mm); } static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) { bool done; write_lock(&tu->filter.rwlock); if (event->hw.target) { list_del(&event->hw.tp_list); done = tu->filter.nr_systemwide || (event->hw.target->flags & PF_EXITING) || uprobe_filter_event(tu, event); } else { tu->filter.nr_systemwide--; done = tu->filter.nr_systemwide; } write_unlock(&tu->filter.rwlock); if (!done) return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); return 0; } static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) { bool done; int err; write_lock(&tu->filter.rwlock); if (event->hw.target) { /* * event->parent != NULL means copy_process(), we can avoid * uprobe_apply(). current->mm must be probed and we can rely * on dup_mmap() which preserves the already installed bp's. * * attr.enable_on_exec means that exec/mmap will install the * breakpoints we need. */ done = tu->filter.nr_systemwide || event->parent || event->attr.enable_on_exec || uprobe_filter_event(tu, event); list_add(&event->hw.tp_list, &tu->filter.perf_events); } else { done = tu->filter.nr_systemwide; tu->filter.nr_systemwide++; } write_unlock(&tu->filter.rwlock); err = 0; if (!done) { err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); if (err) uprobe_perf_close(tu, event); } return err; } static bool uprobe_perf_filter(struct uprobe_consumer *uc, enum uprobe_filter_ctx ctx, struct mm_struct *mm) { struct trace_uprobe *tu; int ret; tu = container_of(uc, struct trace_uprobe, consumer); read_lock(&tu->filter.rwlock); ret = __uprobe_perf_filter(&tu->filter, mm); read_unlock(&tu->filter.rwlock); return ret; } static void __uprobe_perf_func(struct trace_uprobe *tu, unsigned long func, struct pt_regs *regs, struct uprobe_cpu_buffer *ucb, int dsize) { struct trace_event_call *call = &tu->tp.call; struct uprobe_trace_entry_head *entry; struct bpf_prog *prog = call->prog; struct hlist_head *head; void *data; int size, esize; int rctx; if (prog && !trace_call_bpf(prog, regs)) return; esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); size = esize + tu->tp.size + dsize; size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32); if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) return; preempt_disable(); head = this_cpu_ptr(call->perf_events); if (hlist_empty(head)) goto out; entry = perf_trace_buf_alloc(size, NULL, &rctx); if (!entry) goto out; if (is_ret_probe(tu)) { entry->vaddr[0] = func; entry->vaddr[1] = instruction_pointer(regs); data = DATAOF_TRACE_ENTRY(entry, true); } else { entry->vaddr[0] = instruction_pointer(regs); data = DATAOF_TRACE_ENTRY(entry, false); } memcpy(data, ucb->buf, tu->tp.size + dsize); if (size - esize > tu->tp.size + dsize) { int len = tu->tp.size + dsize; memset(data + len, 0, size - esize - len); } perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, head, NULL); out: preempt_enable(); } /* uprobe profile handler */ static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs, struct uprobe_cpu_buffer *ucb, int dsize) { if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) return UPROBE_HANDLER_REMOVE; if (!is_ret_probe(tu)) __uprobe_perf_func(tu, 0, regs, ucb, dsize); return 0; } static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, struct pt_regs *regs, struct uprobe_cpu_buffer *ucb, int dsize) { __uprobe_perf_func(tu, func, regs, ucb, dsize); } #endif /* CONFIG_PERF_EVENTS */ static int trace_uprobe_register(struct trace_event_call *event, enum trace_reg type, void *data) { struct trace_uprobe *tu = event->data; struct trace_event_file *file = data; switch (type) { case TRACE_REG_REGISTER: return probe_event_enable(tu, file, NULL); case TRACE_REG_UNREGISTER: probe_event_disable(tu, file); return 0; #ifdef CONFIG_PERF_EVENTS case TRACE_REG_PERF_REGISTER: return probe_event_enable(tu, NULL, uprobe_perf_filter); case TRACE_REG_PERF_UNREGISTER: probe_event_disable(tu, NULL); return 0; case TRACE_REG_PERF_OPEN: return uprobe_perf_open(tu, data); case TRACE_REG_PERF_CLOSE: return uprobe_perf_close(tu, data); #endif default: return 0; } return 0; } static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) { struct trace_uprobe *tu; struct uprobe_dispatch_data udd; struct uprobe_cpu_buffer *ucb; int dsize, esize; int ret = 0; tu = container_of(con, struct trace_uprobe, consumer); tu->nhit++; udd.tu = tu; udd.bp_addr = instruction_pointer(regs); current->utask->vaddr = (unsigned long) &udd; if (WARN_ON_ONCE(!uprobe_cpu_buffer)) return 0; dsize = __get_data_size(&tu->tp, regs); esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); ucb = uprobe_buffer_get(); store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); if (tu->tp.flags & TP_FLAG_TRACE) ret |= uprobe_trace_func(tu, regs, ucb, dsize); #ifdef CONFIG_PERF_EVENTS if (tu->tp.flags & TP_FLAG_PROFILE) ret |= uprobe_perf_func(tu, regs, ucb, dsize); #endif uprobe_buffer_put(ucb); return ret; } static int uretprobe_dispatcher(struct uprobe_consumer *con, unsigned long func, struct pt_regs *regs) { struct trace_uprobe *tu; struct uprobe_dispatch_data udd; struct uprobe_cpu_buffer *ucb; int dsize, esize; tu = container_of(con, struct trace_uprobe, consumer); udd.tu = tu; udd.bp_addr = func; current->utask->vaddr = (unsigned long) &udd; if (WARN_ON_ONCE(!uprobe_cpu_buffer)) return 0; dsize = __get_data_size(&tu->tp, regs); esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); ucb = uprobe_buffer_get(); store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); if (tu->tp.flags & TP_FLAG_TRACE) uretprobe_trace_func(tu, func, regs, ucb, dsize); #ifdef CONFIG_PERF_EVENTS if (tu->tp.flags & TP_FLAG_PROFILE) uretprobe_perf_func(tu, func, regs, ucb, dsize); #endif uprobe_buffer_put(ucb); return 0; } static struct trace_event_functions uprobe_funcs = { .trace = print_uprobe_event }; static int register_uprobe_event(struct trace_uprobe *tu) { struct trace_event_call *call = &tu->tp.call; int ret; /* Initialize trace_event_call */ INIT_LIST_HEAD(&call->class->fields); call->event.funcs = &uprobe_funcs; call->class->define_fields = uprobe_event_define_fields; if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) return -ENOMEM; ret = register_trace_event(&call->event); if (!ret) { kfree(call->print_fmt); return -ENODEV; } call->flags = TRACE_EVENT_FL_UPROBE; call->class->reg = trace_uprobe_register; call->data = tu; ret = trace_add_event_call(call); if (ret) { pr_info("Failed to register uprobe event: %s\n", trace_event_name(call)); kfree(call->print_fmt); unregister_trace_event(&call->event); } return ret; } static int unregister_uprobe_event(struct trace_uprobe *tu) { int ret; /* tu->event is unregistered in trace_remove_event_call() */ ret = trace_remove_event_call(&tu->tp.call); if (ret) return ret; kfree(tu->tp.call.print_fmt); tu->tp.call.print_fmt = NULL; return 0; } /* Make a trace interface for controling probe points */ static __init int init_uprobe_trace(void) { struct dentry *d_tracer; d_tracer = tracing_init_dentry(); if (IS_ERR(d_tracer)) return 0; trace_create_file("uprobe_events", 0644, d_tracer, NULL, &uprobe_events_ops); /* Profile interface */ trace_create_file("uprobe_profile", 0444, d_tracer, NULL, &uprobe_profile_ops); return 0; } fs_initcall(init_uprobe_trace);