diff options
Diffstat (limited to 'kernel/trace/trace.c')
| -rw-r--r-- | kernel/trace/trace.c | 40 |
1 files changed, 39 insertions, 1 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 02be4ddd4ad5..819e31d0d66c 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3466,7 +3466,31 @@ __find_next_entry(struct trace_iterator *iter, int *ent_cpu, struct trace_entry *trace_find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts) { - return __find_next_entry(iter, ent_cpu, NULL, ent_ts); + /* __find_next_entry will reset ent_size */ + int ent_size = iter->ent_size; + struct trace_entry *entry; + + /* + * 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) { + kfree(iter->temp); + iter->temp = kmalloc(iter->ent_size, GFP_KERNEL); + if (!iter->temp) + return NULL; + } + memcpy(iter->temp, iter->ent, iter->ent_size); + iter->temp_size = iter->ent_size; + iter->ent = iter->temp; + } + entry = __find_next_entry(iter, ent_cpu, NULL, ent_ts); + /* Put back the original ent_size */ + iter->ent_size = ent_size; + + return entry; } /* Find the next real entry, and increment the iterator to the next entry */ @@ -4198,6 +4222,18 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot) goto release; /* + * trace_find_next_entry() may need to save off iter->ent. + * It will place it into the iter->temp buffer. As most + * events are less than 128, allocate a buffer of that size. + * If one is greater, then trace_find_next_entry() will + * allocate a new buffer to adjust for the bigger iter->ent. + * It's not critical if it fails to get allocated here. + */ + iter->temp = kmalloc(128, GFP_KERNEL); + if (iter->temp) + iter->temp_size = 128; + + /* * We make a copy of the current tracer to avoid concurrent * changes on it while we are reading. */ @@ -4269,6 +4305,7 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot) fail: mutex_unlock(&trace_types_lock); kfree(iter->trace); + kfree(iter->temp); kfree(iter->buffer_iter); release: seq_release_private(inode, file); @@ -4344,6 +4381,7 @@ static int tracing_release(struct inode *inode, struct file *file) mutex_destroy(&iter->mutex); free_cpumask_var(iter->started); + kfree(iter->temp); kfree(iter->trace); kfree(iter->buffer_iter); seq_release_private(inode, file); |