From 60311fe2fa8d6e0670d8b51f703ec2738fc35686 Mon Sep 17 00:00:00 2001 From: Anna Henningsen Date: Sat, 2 Feb 2019 15:15:35 +0100 Subject: [PATCH] src: fix race condition in `~NodeTraceBuffer` Libuv does not guarantee that handles have their close callbacks called in the order in which they were added (and in fact, currently calls them in reverse order). This patch ensures that the `flush_signal_` handle is no longer in use (i.e. its close callback has already been run) when we signal to the main thread that `~NodeTraceBuffer` may be destroyed. Credit for debugging goes to Gireesh Punathil. Fixes: https://github.com/nodejs/node/issues/25512 --- src/tracing/node_trace_buffer.cc | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/src/tracing/node_trace_buffer.cc b/src/tracing/node_trace_buffer.cc index 3b7119f6d57f68..796c9f529288e5 100644 --- a/src/tracing/node_trace_buffer.cc +++ b/src/tracing/node_trace_buffer.cc @@ -1,4 +1,5 @@ #include "tracing/node_trace_buffer.h" +#include "util-inl.h" namespace node { namespace tracing { @@ -170,15 +171,25 @@ void NodeTraceBuffer::NonBlockingFlushSignalCb(uv_async_t* signal) { // static void NodeTraceBuffer::ExitSignalCb(uv_async_t* signal) { - NodeTraceBuffer* buffer = reinterpret_cast(signal->data); - uv_close(reinterpret_cast(&buffer->flush_signal_), nullptr); - uv_close(reinterpret_cast(&buffer->exit_signal_), + NodeTraceBuffer* buffer = + ContainerOf(&NodeTraceBuffer::exit_signal_, signal); + + // Close both flush_signal_ and exit_signal_. + uv_close(reinterpret_cast(&buffer->flush_signal_), [](uv_handle_t* signal) { + NodeTraceBuffer* buffer = + ContainerOf(&NodeTraceBuffer::flush_signal_, + reinterpret_cast(signal)); + + uv_close(reinterpret_cast(&buffer->exit_signal_), + [](uv_handle_t* signal) { NodeTraceBuffer* buffer = - reinterpret_cast(signal->data); - Mutex::ScopedLock scoped_lock(buffer->exit_mutex_); - buffer->exited_ = true; - buffer->exit_cond_.Signal(scoped_lock); + ContainerOf(&NodeTraceBuffer::exit_signal_, + reinterpret_cast(signal)); + Mutex::ScopedLock scoped_lock(buffer->exit_mutex_); + buffer->exited_ = true; + buffer->exit_cond_.Signal(scoped_lock); + }); }); }