diff options
| -rw-r--r-- | Documentation/ftrace.txt | 13 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 86 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 3 |
3 files changed, 93 insertions, 9 deletions
diff --git a/Documentation/ftrace.txt b/Documentation/ftrace.txt index 79a80f7..35a78bc 100644 --- a/Documentation/ftrace.txt +++ b/Documentation/ftrace.txt @@ -324,7 +324,7 @@ output. To see what is available, simply cat the file: cat /debug/tracing/trace_options print-parent nosym-offset nosym-addr noverbose noraw nohex nobin \ - noblock nostacktrace nosched-tree nouserstacktrace + noblock nostacktrace nosched-tree nouserstacktrace nosym-userobj To disable one of the options, echo in the option prepended with "no". @@ -381,6 +381,17 @@ Here are the available options: userstacktrace - This option changes the trace. It records a stacktrace of the current userspace thread. + sym-userobj - when user stacktrace are enabled, look up which object the + address belongs to, and print a relative address + This is especially useful when ASLR is on, otherwise you don't + get a chance to resolve the address to object/file/line after the app is no + longer running + + The lookup is performed when you read trace,trace_pipe,latency_trace. Example: + + a.out-1623 [000] 40874.465068: /root/a.out[+0x480] <-/root/a.out[+0 +x494] <- /root/a.out[+0x4a8] <- /lib/libc-2.7.so[+0x1e1a6] + sched-tree - TBD (any users??) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index ced8b4f..62776b7 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -30,6 +30,7 @@ #include <linux/gfp.h> #include <linux/fs.h> #include <linux/kprobes.h> +#include <linux/seq_file.h> #include <linux/writeback.h> #include <linux/stacktrace.h> @@ -276,6 +277,7 @@ static const char *trace_options[] = { "branch", "annotate", "userstacktrace", + "sym-userobj", NULL }; @@ -422,6 +424,28 @@ trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len) return trace_seq_putmem(s, hex, j); } +static int +trace_seq_path(struct trace_seq *s, struct path *path) +{ + unsigned char *p; + + if (s->len >= (PAGE_SIZE - 1)) + return 0; + p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len); + if (!IS_ERR(p)) { + p = mangle_path(s->buffer + s->len, p, "\n"); + if (p) { + s->len = p - s->buffer; + return 1; + } + } else { + s->buffer[s->len++] = '?'; + return 1; + } + + return 0; +} + static void trace_seq_reset(struct trace_seq *s) { @@ -802,6 +826,7 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags, entry->preempt_count = pc & 0xff; entry->pid = (tsk) ? tsk->pid : 0; + entry->tgid = (tsk) ? tsk->tgid : 0; entry->flags = #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) | @@ -1429,28 +1454,73 @@ seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags) return ret; } +static inline int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm, + unsigned long ip, unsigned long sym_flags) +{ + struct file *file = NULL; + unsigned long vmstart = 0; + int ret = 1; + + if (mm) { + const struct vm_area_struct *vma = find_vma(mm, ip); + if (vma) { + file = vma->vm_file; + vmstart = vma->vm_start; + } + } + if (file) { + ret = trace_seq_path(s, &file->f_path); + if (ret) + ret = trace_seq_printf(s, "[+0x%lx]", + ip - vmstart); + } + if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file)) + ret = trace_seq_printf(s, " <" IP_FMT ">", ip); + return ret; +} + static int seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s, - unsigned long sym_flags) + unsigned long sym_flags) { + struct mm_struct *mm = NULL; int ret = 1; unsigned i; + if (trace_flags & TRACE_ITER_SYM_USEROBJ) { + struct task_struct *task; + /* + * we do the lookup on the thread group leader, + * since individual threads might have already quit! + */ + rcu_read_lock(); + task = find_task_by_vpid(entry->ent.tgid); + rcu_read_unlock(); + + if (task) + mm = get_task_mm(task); + } + for (i = 0; i < FTRACE_STACK_ENTRIES; i++) { unsigned long ip = entry->caller[i]; if (ip == ULONG_MAX || !ret) break; - if (i) + if (i && ret) ret = trace_seq_puts(s, " <- "); if (!ip) { - ret = trace_seq_puts(s, "??"); + if (ret) + ret = trace_seq_puts(s, "??"); continue; } - if (ret /*&& (sym_flags & TRACE_ITER_SYM_ADDR)*/) - ret = trace_seq_printf(s, " <" IP_FMT ">", ip); + if (!ret) + break; + if (ret) + ret = seq_print_user_ip(s, mm, ip, sym_flags); } + if (mm) + mmput(mm); return ret; } @@ -1775,8 +1845,7 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) trace_assign_type(field, entry); seq_print_userip_objs(field, s, sym_flags); - if (entry->flags & TRACE_FLAG_CONT) - trace_seq_print_cont(s, iter); + trace_seq_putc(s, '\n'); break; } default: @@ -3581,6 +3650,9 @@ void ftrace_dump(void) atomic_inc(&global_trace.data[cpu]->disabled); } + /* don't look at user memory in panic mode */ + trace_flags &= ~TRACE_ITER_SYM_USEROBJ; + printk(KERN_TRACE "Dumping ftrace buffer:\n"); iter.tr = &global_trace; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 17bb4c8..28c15c2 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -508,7 +508,8 @@ enum trace_iterator_flags { TRACE_ITER_PREEMPTONLY = 0x800, TRACE_ITER_BRANCH = 0x1000, TRACE_ITER_ANNOTATE = 0x2000, - TRACE_ITER_USERSTACKTRACE = 0x4000 + TRACE_ITER_USERSTACKTRACE = 0x4000, + TRACE_ITER_SYM_USEROBJ = 0x8000 }; /* |