diff options
| author | Jing Xia <jing.xia@spreadtrum.com> | 2017-12-26 15:12:53 +0800 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2017-12-27 14:21:16 -0500 |
| commit | 24f2aaf952ee0b59f31c3a18b8b36c9e3d3c2cf5 (patch) | |
| tree | 71b67158bafbf065414d539c2fabffeaae591f44 | |
| parent | ae415fa4c5248a8cf4faabd5a3c20576cb1ad607 (diff) | |
| download | linux-24f2aaf952ee0b59f31c3a18b8b36c9e3d3c2cf5.tar.bz2 | |
tracing: Fix crash when it fails to alloc ring buffer
Double free of the ring buffer happens when it fails to alloc new
ring buffer instance for max_buffer if TRACER_MAX_TRACE is configured.
The root cause is that the pointer is not set to NULL after the buffer
is freed in allocate_trace_buffers(), and the freeing of the ring
buffer is invoked again later if the pointer is not equal to Null,
as:
instance_mkdir()
|-allocate_trace_buffers()
|-allocate_trace_buffer(tr, &tr->trace_buffer...)
|-allocate_trace_buffer(tr, &tr->max_buffer...)
// allocate fail(-ENOMEM),first free
// and the buffer pointer is not set to null
|-ring_buffer_free(tr->trace_buffer.buffer)
// out_free_tr
|-free_trace_buffers()
|-free_trace_buffer(&tr->trace_buffer);
//if trace_buffer is not null, free again
|-ring_buffer_free(buf->buffer)
|-rb_free_cpu_buffer(buffer->buffers[cpu])
// ring_buffer_per_cpu is null, and
// crash in ring_buffer_per_cpu->pages
Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com
Cc: stable@vger.kernel.org
Fixes: 737223fbca3b1 ("tracing: Consolidate buffer allocation code")
Signed-off-by: Jing Xia <jing.xia@spreadtrum.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| -rw-r--r-- | kernel/trace/trace.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 73652d5318b2..0e53d46544b8 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -7603,7 +7603,9 @@ static int allocate_trace_buffers(struct trace_array *tr, int size) allocate_snapshot ? size : 1); if (WARN_ON(ret)) { ring_buffer_free(tr->trace_buffer.buffer); + tr->trace_buffer.buffer = NULL; free_percpu(tr->trace_buffer.data); + tr->trace_buffer.data = NULL; return -ENOMEM; } tr->allocated_snapshot = allocate_snapshot; |