diff options
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 6519b7afc499..8d2b98812625 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3472,6 +3472,9 @@ __find_next_entry(struct trace_iterator *iter, int *ent_cpu, return next; } +#define STATIC_TEMP_BUF_SIZE 128 +static char static_temp_buf[STATIC_TEMP_BUF_SIZE]; + /* Find the next real entry, without updating the iterator itself */ struct trace_entry *trace_find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts) @@ -3481,12 +3484,25 @@ struct trace_entry *trace_find_next_entry(struct trace_iterator *iter, struct trace_entry *entry; /* + * If called from ftrace_dump(), then the iter->temp buffer + * will be the static_temp_buf and not created from kmalloc. + * If the entry size is greater than the buffer, we can + * not save it. Just return NULL in that case. This is only + * used to add markers when two consecutive events' time + * stamps have a large delta. See trace_print_lat_context() + */ + if (iter->temp == static_temp_buf && + STATIC_TEMP_BUF_SIZE < ent_size) + return NULL; + + /* * The __find_next_entry() may call peek_next_entry(), which may * call ring_buffer_peek() that may make the contents of iter->ent * undefined. Need to copy iter->ent now. */ if (iter->ent && iter->ent != iter->temp) { - if (!iter->temp || iter->temp_size < iter->ent_size) { + if ((!iter->temp || iter->temp_size < iter->ent_size) && + !WARN_ON_ONCE(iter->temp == static_temp_buf)) { kfree(iter->temp); iter->temp = kmalloc(iter->ent_size, GFP_KERNEL); if (!iter->temp) @@ -9203,6 +9219,9 @@ void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) /* Simulate the iterator */ trace_init_global_iter(&iter); + /* Can not use kmalloc for iter.temp */ + iter.temp = static_temp_buf; + iter.temp_size = STATIC_TEMP_BUF_SIZE; for_each_tracing_cpu(cpu) { atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled); |