diff options
Diffstat (limited to 'kernel/trace/trace.c')
| -rw-r--r-- | kernel/trace/trace.c | 485 |
1 files changed, 374 insertions, 111 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 54d5270a5042..66f829c47bec 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -40,6 +40,7 @@ #include <linux/poll.h> #include <linux/nmi.h> #include <linux/fs.h> +#include <linux/trace.h> #include <linux/sched/rt.h> #include "trace.h" @@ -68,6 +69,7 @@ bool __read_mostly tracing_selftest_disabled; /* Pipe tracepoints to printk */ struct trace_iterator *tracepoint_print_iter; int tracepoint_printk; +static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key); /* For tracers that don't implement custom flags */ static struct tracer_opt dummy_tracer_opt[] = { @@ -738,6 +740,31 @@ static inline void ftrace_trace_stack(struct trace_array *tr, #endif +static __always_inline void +trace_event_setup(struct ring_buffer_event *event, + int type, unsigned long flags, int pc) +{ + struct trace_entry *ent = ring_buffer_event_data(event); + + tracing_generic_entry_update(ent, flags, pc); + ent->type = type; +} + +static __always_inline struct ring_buffer_event * +__trace_buffer_lock_reserve(struct ring_buffer *buffer, + int type, + unsigned long len, + unsigned long flags, int pc) +{ + struct ring_buffer_event *event; + + event = ring_buffer_lock_reserve(buffer, len); + if (event != NULL) + trace_event_setup(event, type, flags, pc); + + return event; +} + static void tracer_tracing_on(struct trace_array *tr) { if (tr->trace_buffer.buffer) @@ -767,6 +794,22 @@ void tracing_on(void) } EXPORT_SYMBOL_GPL(tracing_on); + +static __always_inline void +__buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event) +{ + __this_cpu_write(trace_cmdline_save, true); + + /* If this is the temp buffer, we need to commit fully */ + if (this_cpu_read(trace_buffered_event) == event) { + /* Length is in event->array[0] */ + ring_buffer_write(buffer, event->array[0], &event->array[1]); + /* Release the temp buffer */ + this_cpu_dec(trace_buffered_event_cnt); + } else + ring_buffer_unlock_commit(buffer, event); +} + /** * __trace_puts - write a constant string into the trace buffer. * @ip: The address of the caller @@ -794,8 +837,8 @@ int __trace_puts(unsigned long ip, const char *str, int size) local_save_flags(irq_flags); buffer = global_trace.trace_buffer.buffer; - event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc, - irq_flags, pc); + event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc, + irq_flags, pc); if (!event) return 0; @@ -842,8 +885,8 @@ int __trace_bputs(unsigned long ip, const char *str) local_save_flags(irq_flags); buffer = global_trace.trace_buffer.buffer; - event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size, - irq_flags, pc); + event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size, + irq_flags, pc); if (!event) return 0; @@ -1907,35 +1950,19 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags, #endif ((pc & NMI_MASK ) ? TRACE_FLAG_NMI : 0) | ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) | - ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) | + ((pc & SOFTIRQ_OFFSET) ? TRACE_FLAG_SOFTIRQ : 0) | (tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) | (test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0); } EXPORT_SYMBOL_GPL(tracing_generic_entry_update); -static __always_inline void -trace_event_setup(struct ring_buffer_event *event, - int type, unsigned long flags, int pc) -{ - struct trace_entry *ent = ring_buffer_event_data(event); - - tracing_generic_entry_update(ent, flags, pc); - ent->type = type; -} - struct ring_buffer_event * trace_buffer_lock_reserve(struct ring_buffer *buffer, int type, unsigned long len, unsigned long flags, int pc) { - struct ring_buffer_event *event; - - event = ring_buffer_lock_reserve(buffer, len); - if (event != NULL) - trace_event_setup(event, type, flags, pc); - - return event; + return __trace_buffer_lock_reserve(buffer, type, len, flags, pc); } DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event); @@ -2049,21 +2076,6 @@ void trace_buffered_event_disable(void) preempt_enable(); } -void -__buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event) -{ - __this_cpu_write(trace_cmdline_save, true); - - /* If this is the temp buffer, we need to commit fully */ - if (this_cpu_read(trace_buffered_event) == event) { - /* Length is in event->array[0] */ - ring_buffer_write(buffer, event->array[0], &event->array[1]); - /* Release the temp buffer */ - this_cpu_dec(trace_buffered_event_cnt); - } else - ring_buffer_unlock_commit(buffer, event); -} - static struct ring_buffer *temp_buffer; struct ring_buffer_event * @@ -2090,8 +2102,8 @@ trace_event_buffer_lock_reserve(struct ring_buffer **current_rb, this_cpu_dec(trace_buffered_event_cnt); } - entry = trace_buffer_lock_reserve(*current_rb, - type, len, flags, pc); + entry = __trace_buffer_lock_reserve(*current_rb, + type, len, flags, pc); /* * If tracing is off, but we have triggers enabled * we still need to look at the event data. Use the temp_buffer @@ -2100,13 +2112,88 @@ trace_event_buffer_lock_reserve(struct ring_buffer **current_rb, */ if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) { *current_rb = temp_buffer; - entry = trace_buffer_lock_reserve(*current_rb, - type, len, flags, pc); + entry = __trace_buffer_lock_reserve(*current_rb, + type, len, flags, pc); } return entry; } EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve); +static DEFINE_SPINLOCK(tracepoint_iter_lock); +static DEFINE_MUTEX(tracepoint_printk_mutex); + +static void output_printk(struct trace_event_buffer *fbuffer) +{ + struct trace_event_call *event_call; + struct trace_event *event; + unsigned long flags; + struct trace_iterator *iter = tracepoint_print_iter; + + /* We should never get here if iter is NULL */ + if (WARN_ON_ONCE(!iter)) + return; + + event_call = fbuffer->trace_file->event_call; + if (!event_call || !event_call->event.funcs || + !event_call->event.funcs->trace) + return; + + event = &fbuffer->trace_file->event_call->event; + + spin_lock_irqsave(&tracepoint_iter_lock, flags); + trace_seq_init(&iter->seq); + iter->ent = fbuffer->entry; + event_call->event.funcs->trace(iter, 0, event); + trace_seq_putc(&iter->seq, 0); + printk("%s", iter->seq.buffer); + + spin_unlock_irqrestore(&tracepoint_iter_lock, flags); +} + +int tracepoint_printk_sysctl(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos) +{ + int save_tracepoint_printk; + int ret; + + mutex_lock(&tracepoint_printk_mutex); + save_tracepoint_printk = tracepoint_printk; + + ret = proc_dointvec(table, write, buffer, lenp, ppos); + + /* + * This will force exiting early, as tracepoint_printk + * is always zero when tracepoint_printk_iter is not allocated + */ + if (!tracepoint_print_iter) + tracepoint_printk = 0; + + if (save_tracepoint_printk == tracepoint_printk) + goto out; + + if (tracepoint_printk) + static_key_enable(&tracepoint_printk_key.key); + else + static_key_disable(&tracepoint_printk_key.key); + + out: + mutex_unlock(&tracepoint_printk_mutex); + + return ret; +} + +void trace_event_buffer_commit(struct trace_event_buffer *fbuffer) +{ + if (static_key_false(&tracepoint_printk_key.key)) + output_printk(fbuffer); + + event_trigger_unlock_commit(fbuffer->trace_file, fbuffer->buffer, + fbuffer->event, fbuffer->entry, + fbuffer->flags, fbuffer->pc); +} +EXPORT_SYMBOL_GPL(trace_event_buffer_commit); + void trace_buffer_unlock_commit_regs(struct trace_array *tr, struct ring_buffer *buffer, struct ring_buffer_event *event, @@ -2129,6 +2216,139 @@ void trace_buffer_unlock_commit_regs(struct trace_array *tr, ftrace_trace_userstack(buffer, flags, pc); } +/* + * Similar to trace_buffer_unlock_commit_regs() but do not dump stack. + */ +void +trace_buffer_unlock_commit_nostack(struct ring_buffer *buffer, + struct ring_buffer_event *event) +{ + __buffer_unlock_commit(buffer, event); +} + +static void +trace_process_export(struct trace_export *export, + struct ring_buffer_event *event) +{ + struct trace_entry *entry; + unsigned int size = 0; + + entry = ring_buffer_event_data(event); + size = ring_buffer_event_length(event); + export->write(entry, size); +} + +static DEFINE_MUTEX(ftrace_export_lock); + +static struct trace_export __rcu *ftrace_exports_list __read_mostly; + +static DEFINE_STATIC_KEY_FALSE(ftrace_exports_enabled); + +static inline void ftrace_exports_enable(void) +{ + static_branch_enable(&ftrace_exports_enabled); +} + +static inline void ftrace_exports_disable(void) +{ + static_branch_disable(&ftrace_exports_enabled); +} + +void ftrace_exports(struct ring_buffer_event *event) +{ + struct trace_export *export; + + preempt_disable_notrace(); + + export = rcu_dereference_raw_notrace(ftrace_exports_list); + while (export) { + trace_process_export(export, event); + export = rcu_dereference_raw_notrace(export->next); + } + + preempt_enable_notrace(); +} + +static inline void +add_trace_export(struct trace_export **list, struct trace_export *export) +{ + rcu_assign_pointer(export->next, *list); + /* + * We are entering export into the list but another + * CPU might be walking that list. We need to make sure + * the export->next pointer is valid before another CPU sees + * the export pointer included into the list. + */ + rcu_assign_pointer(*list, export); +} + +static inline int +rm_trace_export(struct trace_export **list, struct trace_export *export) +{ + struct trace_export **p; + + for (p = list; *p != NULL; p = &(*p)->next) + if (*p == export) + break; + + if (*p != export) + return -1; + + rcu_assign_pointer(*p, (*p)->next); + + return 0; +} + +static inline void +add_ftrace_export(struct trace_export **list, struct trace_export *export) +{ + if (*list == NULL) + ftrace_exports_enable(); + + add_trace_export(list, export); +} + +static inline int +rm_ftrace_export(struct trace_export **list, struct trace_export *export) +{ + int ret; + + ret = rm_trace_export(list, export); + if (*list == NULL) + ftrace_exports_disable(); + + return ret; +} + +int register_ftrace_export(struct trace_export *export) +{ + if (WARN_ON_ONCE(!export->write)) + return -1; + + mutex_lock(&ftrace_export_lock); + + add_ftrace_export(&ftrace_exports_list, export); + + mutex_unlock(&ftrace_export_lock); + + return 0; +} +EXPORT_SYMBOL_GPL(register_ftrace_export); + +int unregister_ftrace_export(struct trace_export *export) +{ + int ret; + + mutex_lock(&ftrace_export_lock); + + ret = rm_ftrace_export(&ftrace_exports_list, export); + + mutex_unlock(&ftrace_export_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(unregister_ftrace_export); + void trace_function(struct trace_array *tr, unsigned long ip, unsigned long parent_ip, unsigned long flags, @@ -2139,16 +2359,19 @@ trace_function(struct trace_array *tr, struct ring_buffer_event *event; struct ftrace_entry *entry; - event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry), - flags, pc); + event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry), + flags, pc); if (!event) return; entry = ring_buffer_event_data(event); entry->ip = ip; entry->parent_ip = parent_ip; - if (!call_filter_check_discard(call, entry, buffer, event)) + if (!call_filter_check_discard(call, entry, buffer, event)) { + if (static_branch_unlikely(&ftrace_exports_enabled)) + ftrace_exports(event); __buffer_unlock_commit(buffer, event); + } } #ifdef CONFIG_STACKTRACE @@ -2216,8 +2439,8 @@ static void __ftrace_trace_stack(struct ring_buffer *buffer, size *= sizeof(unsigned long); - event = trace_buffer_lock_reserve(buffer, TRACE_STACK, - sizeof(*entry) + size, flags, pc); + event = __trace_buffer_lock_reserve(buffer, TRACE_STACK, + sizeof(*entry) + size, flags, pc); if (!event) goto out; entry = ring_buffer_event_data(event); @@ -2318,8 +2541,8 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) __this_cpu_inc(user_stack_count); - event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK, - sizeof(*entry), flags, pc); + event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK, + sizeof(*entry), flags, pc); if (!event) goto out_drop_count; entry = ring_buffer_event_data(event); @@ -2489,8 +2712,8 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args) local_save_flags(flags); size = sizeof(*entry) + sizeof(u32) * len; buffer = tr->trace_buffer.buffer; - event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size, - flags, pc); + event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size, + flags, pc); if (!event) goto out; entry = ring_buffer_event_data(event); @@ -2545,8 +2768,8 @@ __trace_array_vprintk(struct ring_buffer *buffer, local_save_flags(flags); size = sizeof(*entry) + len + 1; - event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, - flags, pc); + event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, + flags, pc); if (!event) goto out; entry = ring_buffer_event_data(event); @@ -4055,6 +4278,7 @@ static const char readme_msg[] = " x86-tsc: TSC cycle counter\n" #endif "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n" + "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n" " tracing_cpumask\t- Limit which CPUs to trace\n" " instances\t\t- Make sub-buffers with: mkdir instances/foo\n" "\t\t\t Remove sub-buffer with rmdir\n" @@ -4066,7 +4290,7 @@ static const char readme_msg[] = "\n available_filter_functions - list of functions that can be filtered on\n" " set_ftrace_filter\t- echo function name in here to only trace these\n" "\t\t\t functions\n" - "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n" + "\t accepts: func_full_name or glob-matching-pattern\n" "\t modules: Can select a group via module\n" "\t Format: :mod:<module-name>\n" "\t example: echo :mod:ext3 > set_ftrace_filter\n" @@ -5519,21 +5743,18 @@ static ssize_t tracing_mark_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *fpos) { - unsigned long addr = (unsigned long)ubuf; struct trace_array *tr = filp->private_data; struct ring_buffer_event *event; struct ring_buffer *buffer; struct print_entry *entry; unsigned long irq_flags; - struct page *pages[2]; - void *map_page[2]; - int nr_pages = 1; + const char faulted[] = "<faulted>"; ssize_t written; - int offset; int size; int len; - int ret; - int i; + +/* Used in tracing_mark_raw_write() as well */ +#define FAULTED_SIZE (sizeof(faulted) - 1) /* '\0' is already accounted for */ if (tracing_disabled) return -EINVAL; @@ -5544,60 +5765,33 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, if (cnt > TRACE_BUF_SIZE) cnt = TRACE_BUF_SIZE; - /* - * Userspace is injecting traces into the kernel trace buffer. - * We want to be as non intrusive as possible. - * To do so, we do not want to allocate any special buffers - * or take any locks, but instead write the userspace data - * straight into the ring buffer. - * - * First we need to pin the userspace buffer into memory, - * which, most likely it is, because it just referenced it. - * But there's no guarantee that it is. By using get_user_pages_fast() - * and kmap_atomic/kunmap_atomic() we can get access to the - * pages directly. We then write the data directly into the - * ring buffer. - */ BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE); - /* check if we cross pages */ - if ((addr & PAGE_MASK) != ((addr + cnt) & PAGE_MASK)) - nr_pages = 2; - - offset = addr & (PAGE_SIZE - 1); - addr &= PAGE_MASK; - - ret = get_user_pages_fast(addr, nr_pages, 0, pages); - if (ret < nr_pages) { - while (--ret >= 0) - put_page(pages[ret]); - written = -EFAULT; - goto out; - } + local_save_flags(irq_flags); + size = sizeof(*entry) + cnt + 2; /* add '\0' and possible '\n' */ - for (i = 0; i < nr_pages; i++) - map_page[i] = kmap_atomic(pages[i]); + /* If less than "<faulted>", then make sure we can still add that */ + if (cnt < FAULTED_SIZE) + size += FAULTED_SIZE - cnt; - local_save_flags(irq_flags); - size = sizeof(*entry) + cnt + 2; /* possible \n added */ buffer = tr->trace_buffer.buffer; - event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, - irq_flags, preempt_count()); - if (!event) { + event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, + irq_flags, preempt_count()); + if (unlikely(!event)) /* Ring buffer disabled, return as if not open for write */ - written = -EBADF; - goto out_unlock; - } + return -EBADF; entry = ring_buffer_event_data(event); entry->ip = _THIS_IP_; - if (nr_pages == 2) { - len = PAGE_SIZE - offset; - memcpy(&entry->buf, map_page[0] + offset, len); - memcpy(&entry->buf[len], map_page[1], cnt - len); + len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt); + if (len) { + memcpy(&entry->buf, faulted, FAULTED_SIZE); + cnt = FAULTED_SIZE; + written = -EFAULT; } else - memcpy(&entry->buf, map_page[0] + offset, cnt); + written = cnt; + len = cnt; if (entry->buf[cnt - 1] != '\n') { entry->buf[cnt] = '\n'; @@ -5607,16 +5801,73 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, __buffer_unlock_commit(buffer, event); - written = cnt; + if (written > 0) + *fpos += written; - *fpos += written; + return written; +} + +/* Limit it for now to 3K (including tag) */ +#define RAW_DATA_MAX_SIZE (1024*3) + +static ssize_t +tracing_mark_raw_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *fpos) +{ + struct trace_array *tr = filp->private_data; + struct ring_buffer_event *event; + struct ring_buffer *buffer; + struct raw_data_entry *entry; + const char faulted[] = "<faulted>"; + unsigned long irq_flags; + ssize_t written; + int size; + int len; + +#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int)) + + if (tracing_disabled) + return -EINVAL; + + if (!(tr->trace_flags & TRACE_ITER_MARKERS)) + return -EINVAL; + + /* The marker must at least have a tag id */ + if (cnt < sizeof(unsigned int) || cnt > RAW_DATA_MAX_SIZE) + return -EINVAL; + + if (cnt > TRACE_BUF_SIZE) + cnt = TRACE_BUF_SIZE; + + BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE); + + local_save_flags(irq_flags); + size = sizeof(*entry) + cnt; + if (cnt < FAULT_SIZE_ID) + size += FAULT_SIZE_ID - cnt; + + buffer = tr->trace_buffer.buffer; + event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size, + irq_flags, preempt_count()); + if (!event) + /* Ring buffer disabled, return as if not open for write */ + return -EBADF; + + entry = ring_buffer_event_data(event); + + len = __copy_from_user_inatomic(&entry->id, ubuf, cnt); + if (len) { + entry->id = -1; + memcpy(&entry->buf, faulted, FAULTED_SIZE); + written = -EFAULT; + } else + written = cnt; + + __buffer_unlock_commit(buffer, event); + + if (written > 0) + *fpos += written; - out_unlock: - for (i = nr_pages - 1; i >= 0; i--) { - kunmap_atomic(map_page[i]); - put_page(pages[i]); - } - out: return written; } @@ -5946,6 +6197,13 @@ static const struct file_operations tracing_mark_fops = { .release = tracing_release_generic_tr, }; +static const struct file_operations tracing_mark_raw_fops = { + .open = tracing_open_generic_tr, + .write = tracing_mark_raw_write, + .llseek = generic_file_llseek, + .release = tracing_release_generic_tr, +}; + static const struct file_operations trace_clock_fops = { .open = tracing_clock_open, .read = seq_read, @@ -7215,6 +7473,9 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer) trace_create_file("trace_marker", 0220, d_tracer, tr, &tracing_mark_fops); + trace_create_file("trace_marker_raw", 0220, d_tracer, + tr, &tracing_mark_raw_fops); + trace_create_file("trace_clock", 0644, d_tracer, tr, &trace_clock_fops); @@ -7752,6 +8013,8 @@ void __init trace_init(void) kmalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL); if (WARN_ON(!tracepoint_print_iter)) tracepoint_printk = 0; + else + static_key_enable(&tracepoint_printk_key.key); } tracer_alloc_buffers(); trace_event_init(); |