tracing: Allocate the snapshot buffer before enabling probe
[GitHub/LineageOS/android_kernel_samsung_universal7580.git] / kernel / trace / trace.c
index 18cdf91b2f853d34ab09c1ae90f1d7c0ba2e300a..dde12f326b529cc8b0a82c46bcdd6ca0295f1ccb 100644 (file)
@@ -730,6 +730,7 @@ static const char *trace_options[] = {
        "irq-info",
        "markers",
        "function-trace",
+       "print-tgid",
        NULL
 };
 
@@ -1242,6 +1243,7 @@ void tracing_reset_all_online_cpus(void)
 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
+static unsigned saved_tgids[SAVED_CMDLINES];
 static int cmdline_idx;
 static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 
@@ -1443,6 +1445,7 @@ static int trace_save_cmdline(struct task_struct *tsk)
        }
 
        memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
+       saved_tgids[idx] = tsk->tgid;
 
        arch_spin_unlock(&trace_cmdline_lock);
 
@@ -1480,6 +1483,25 @@ void trace_find_cmdline(int pid, char comm[])
        preempt_enable();
 }
 
+int trace_find_tgid(int pid)
+{
+       unsigned map;
+       int tgid;
+
+       preempt_disable();
+       arch_spin_lock(&trace_cmdline_lock);
+       map = map_pid_to_cmdline[pid];
+       if (map != NO_CMDLINE_MAP)
+               tgid = saved_tgids[map];
+       else
+               tgid = -1;
+
+       arch_spin_unlock(&trace_cmdline_lock);
+       preempt_enable();
+
+       return tgid;
+}
+
 void tracing_record_cmdline(struct task_struct *tsk)
 {
        if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on())
@@ -2435,6 +2457,13 @@ static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m)
        seq_puts(m, "#              | |       |          |         |\n");
 }
 
+static void print_func_help_header_tgid(struct trace_buffer *buf, struct seq_file *m)
+{
+       print_event_info(buf, m);
+       seq_puts(m, "#           TASK-PID    TGID   CPU#      TIMESTAMP  FUNCTION\n");
+       seq_puts(m, "#              | |        |      |          |         |\n");
+}
+
 static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m)
 {
        print_event_info(buf, m);
@@ -2447,6 +2476,18 @@ static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file
        seq_puts(m, "#              | |       |   ||||       |         |\n");
 }
 
+static void print_func_help_header_irq_tgid(struct trace_buffer *buf, struct seq_file *m)
+{
+       print_event_info(buf, m);
+       seq_puts(m, "#                                      _-----=> irqs-off\n");
+       seq_puts(m, "#                                     / _----=> need-resched\n");
+       seq_puts(m, "#                                    | / _---=> hardirq/softirq\n");
+       seq_puts(m, "#                                    || / _--=> preempt-depth\n");
+       seq_puts(m, "#                                    ||| /     delay\n");
+       seq_puts(m, "#           TASK-PID    TGID   CPU#  ||||    TIMESTAMP  FUNCTION\n");
+       seq_puts(m, "#              | |        |      |   ||||       |         |\n");
+}
+
 void
 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
 {
@@ -2747,9 +2788,15 @@ void trace_default_header(struct seq_file *m)
        } else {
                if (!(trace_flags & TRACE_ITER_VERBOSE)) {
                        if (trace_flags & TRACE_ITER_IRQ_INFO)
-                               print_func_help_header_irq(iter->trace_buffer, m);
+                               if (trace_flags & TRACE_ITER_TGID)
+                                       print_func_help_header_irq_tgid(iter->trace_buffer, m);
+                               else
+                                       print_func_help_header_irq(iter->trace_buffer, m);
                        else
-                               print_func_help_header(iter->trace_buffer, m);
+                               if (trace_flags & TRACE_ITER_TGID)
+                                       print_func_help_header_tgid(iter->trace_buffer, m);
+                               else
+                                       print_func_help_header(iter->trace_buffer, m);
                }
        }
 }
@@ -3601,9 +3648,53 @@ tracing_saved_cmdlines_read(struct file *file, char __user *ubuf,
 }
 
 static const struct file_operations tracing_saved_cmdlines_fops = {
-    .open       = tracing_open_generic,
-    .read       = tracing_saved_cmdlines_read,
-    .llseek    = generic_file_llseek,
+       .open   = tracing_open_generic,
+       .read   = tracing_saved_cmdlines_read,
+       .llseek = generic_file_llseek,
+};
+
+static ssize_t
+tracing_saved_tgids_read(struct file *file, char __user *ubuf,
+                               size_t cnt, loff_t *ppos)
+{
+       char *file_buf;
+       char *buf;
+       int len = 0;
+       int pid;
+       int i;
+
+       file_buf = kmalloc(SAVED_CMDLINES*(16+1+16), GFP_KERNEL);
+       if (!file_buf)
+               return -ENOMEM;
+
+       buf = file_buf;
+
+       for (i = 0; i < SAVED_CMDLINES; i++) {
+               int tgid;
+               int r;
+
+               pid = map_cmdline_to_pid[i];
+               if (pid == -1 || pid == NO_CMDLINE_MAP)
+                       continue;
+
+               tgid = trace_find_tgid(pid);
+               r = sprintf(buf, "%d %d\n", pid, tgid);
+               buf += r;
+               len += r;
+       }
+
+       len = simple_read_from_buffer(ubuf, cnt, ppos,
+                                     file_buf, len);
+
+       kfree(file_buf);
+
+       return len;
+}
+
+static const struct file_operations tracing_saved_tgids_fops = {
+       .open   = tracing_open_generic,
+       .read   = tracing_saved_tgids_read,
+       .llseek = generic_file_llseek,
 };
 
 static ssize_t
@@ -4121,13 +4212,6 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
        struct trace_array *tr = iter->tr;
        ssize_t sret;
 
-       /* return any leftover data */
-       sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
-       if (sret != -EBUSY)
-               return sret;
-
-       trace_seq_init(&iter->seq);
-
        /* copy the tracer to avoid using a global lock all around */
        mutex_lock(&trace_types_lock);
        if (unlikely(iter->trace->name != tr->current_trace->name))
@@ -4140,6 +4224,14 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
         * is protected.
         */
        mutex_lock(&iter->mutex);
+
+       /* return any leftover data */
+       sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
+       if (sret != -EBUSY)
+               goto out;
+
+       trace_seq_init(&iter->seq);
+
        if (iter->trace->read) {
                sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
                if (sret)
@@ -4351,7 +4443,10 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
 
        spd.nr_pages = i;
 
-       ret = splice_to_pipe(pipe, &spd);
+       if (i)
+               ret = splice_to_pipe(pipe, &spd);
+       else
+               ret = 0;
 out:
        splice_shrink_spd(&spd);
        return ret;
@@ -4588,7 +4683,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
        *fpos += written;
 
  out_unlock:
-       for (i = 0; i < nr_pages; i++){
+       for (i = nr_pages - 1; i >= 0; i--) {
                kunmap_atomic(map_page[i]);
                put_page(pages[i]);
        }
@@ -5165,11 +5260,6 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
        }
 #endif
 
-       if (splice_grow_spd(pipe, &spd)) {
-               ret = -ENOMEM;
-               goto out;
-       }
-
        if (*ppos & (PAGE_SIZE - 1)) {
                ret = -EINVAL;
                goto out;
@@ -5183,6 +5273,11 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
                len &= PAGE_MASK;
        }
 
+       if (splice_grow_spd(pipe, &spd)) {
+               ret = -ENOMEM;
+               goto out;
+       }
+
  again:
        trace_access_lock(iter->cpu_file);
        entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
@@ -5238,21 +5333,22 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
        if (!spd.nr_pages) {
                if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK)) {
                        ret = -EAGAIN;
-                       goto out;
+                       goto out_shrink;
                }
                mutex_unlock(&trace_types_lock);
                ret = iter->trace->wait_pipe(iter);
                mutex_lock(&trace_types_lock);
                if (ret)
-                       goto out;
+                       goto out_shrink;
                if (signal_pending(current)) {
                        ret = -EINTR;
-                       goto out;
+                       goto out_shrink;
                }
                goto again;
        }
 
        ret = splice_to_pipe(pipe, &spd);
+out_shrink:
        splice_shrink_spd(&spd);
 out:
        mutex_unlock(&trace_types_lock);
@@ -5463,11 +5559,13 @@ ftrace_trace_snapshot_callback(struct ftrace_hash *hash,
                return ret;
 
  out_reg:
-       ret = register_ftrace_function_probe(glob, ops, count);
+       ret = alloc_snapshot(&global_trace);
+       if (ret < 0)
+               goto out;
 
-       if (ret >= 0)
-               alloc_snapshot(&global_trace);
+       ret = register_ftrace_function_probe(glob, ops, count);
 
+ out:
        return ret < 0 ? ret : 0;
 }
 
@@ -6063,7 +6161,7 @@ static int instance_mkdir (struct inode *inode, struct dentry *dentry, umode_t m
        int ret;
 
        /* Paranoid: Make sure the parent is the "instances" directory */
-       parent = hlist_entry(inode->i_dentry.first, struct dentry, d_alias);
+       parent = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias);
        if (WARN_ON_ONCE(parent != trace_instance_dir))
                return -ENOENT;
 
@@ -6090,7 +6188,7 @@ static int instance_rmdir(struct inode *inode, struct dentry *dentry)
        int ret;
 
        /* Paranoid: Make sure the parent is the "instances" directory */
-       parent = hlist_entry(inode->i_dentry.first, struct dentry, d_alias);
+       parent = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias);
        if (WARN_ON_ONCE(parent != trace_instance_dir))
                return -ENOENT;
 
@@ -6157,6 +6255,9 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
        trace_create_file("trace_marker", 0220, d_tracer,
                          tr, &tracing_mark_fops);
 
+       trace_create_file("saved_tgids", 0444, d_tracer,
+                         tr, &tracing_saved_tgids_fops);
+
        trace_create_file("trace_clock", 0644, d_tracer, tr,
                          &trace_clock_fops);