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authorJing Xia <jing.xia@spreadtrum.com>2017-12-26 15:12:53 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-01-02 20:35:07 +0100
commit81e155e7b023dd8967ddead36edf8a6a0e2ba72b (patch)
tree75d05eca1a2139bef6c7a4cfc95c25013d48e9be /kernel/trace
parent5dc4cd2688e39b0286e9a4b815c9bf5e71b5a685 (diff)
tracing: Fix crash when it fails to alloc ring buffer
commit 24f2aaf952ee0b59f31c3a18b8b36c9e3d3c2cf5 upstream. 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 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index bbc117d73d19..15b02645ce8b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6979,7 +6979,9 @@ 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;