Eric Lee / smarc-fsl-linux-kernel

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Commit 85951842a1020669f0a9eb0f0d1853b41341f097

Authored by Li Zefan
Committed by Ingo Molnar
1 parent f129e965be

ftrace: Don't increment @pos in g_start() 

It's wrong to increment @pos in g_start(). It causes some entries
lost when reading set_graph_function, if the output of the file
is larger than PAGE_SIZE.

Reviewed-by: Liming Wang <liming.wang@windriver.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A418738.7090401@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Showing 1 changed file with 10 additions and 11 deletions Side-by-side Diff

kernel/trace/ftrace.c
Diff comments   View file @ 8595184
... ... @@ -2500,32 +2500,31 @@
2500 2500 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
2501 2501  
2502 2502 static void *
2503   -g_next(struct seq_file *m, void *v, loff_t *pos)
  2503 +__g_next(struct seq_file *m, loff_t *pos)
2504 2504 {
2505 2505 unsigned long *array = m->private;
2506   - int index = *pos;
2507 2506  
2508   - (*pos)++;
2509   -
2510   - if (index >= ftrace_graph_count)
  2507 + if (*pos >= ftrace_graph_count)
2511 2508 return NULL;
  2509 + return &array[*pos];
  2510 +}
2512 2511  
2513   - return &array[index];
  2512 +static void *
  2513 +g_next(struct seq_file *m, void *v, loff_t *pos)
  2514 +{
  2515 + (*pos)++;
  2516 + return __g_next(m, pos);
2514 2517 }
2515 2518  
2516 2519 static void *g_start(struct seq_file *m, loff_t *pos)
2517 2520 {
2518   - void *p = NULL;
2519   -
2520 2521 mutex_lock(&graph_lock);
2521 2522  
2522 2523 /* Nothing, tell g_show to print all functions are enabled */
2523 2524 if (!ftrace_graph_count && !*pos)
2524 2525 return (void *)1;
2525 2526  
2526   - p = g_next(m, p, pos);
2527   -
2528   - return p;
  2527 + return __g_next(m, pos);
2529 2528 }
2530 2529  
2531 2530 static void g_stop(struct seq_file *m, void *p)