Author: Augusto Noronha Date: 2023-09-25T11:17:42-07:00 New Revision: 962ef991da2836775191435fb732fc61ec07d5e6
URL: https://github.com/llvm/llvm-project/commit/962ef991da2836775191435fb732fc61ec07d5e6 DIFF: https://github.com/llvm/llvm-project/commit/962ef991da2836775191435fb732fc61ec07d5e6.diff LOG: [lldb] Protect RNBRemote from a data race Summary: Thread sanitizer reports the following data race: ``` Write of size 8 at 0x000103303e70 by thread T1 (mutexes: write M0): #0 RNBRemote::CommDataReceived(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&) RNBRemote.cpp:1075 (debugserver:arm64+0x100038db8) (BuildId: f130b34f693c4f3eba96139104af2b7132000000200000000100000000000e00) #1 RNBRemote::ThreadFunctionReadRemoteData(void*) RNBRemote.cpp:1180 (debugserver:arm64+0x1000391dc) (BuildId: f130b34f693c4f3eba96139104af2b7132000000200000000100000000000e00) Previous read of size 8 at 0x000103303e70 by main thread: #0 RNBRemote::GetPacketPayload(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>&) RNBRemote.cpp:797 (debugserver:arm64+0x100037c5c) (BuildId: f130b34f693c4f3eba96139104af2b7132000000200000000100000000000e00) #1 RNBRemote::GetPacket(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>&, RNBRemote::Packet&, bool) RNBRemote.cpp:907 (debugserver:arm64+0x1000378cc) (BuildId: f130b34f693c4f3eba96139104af2b7132000000200000000100000000000e00) ``` RNBRemote already has a mutex, extend its usage to protect the read of m_rx_packets. Reviewers: jdevlieghere, bulbazord, jingham Subscribers: Added: Modified: lldb/tools/debugserver/source/RNBRemote.cpp Removed: ################################################################################ diff --git a/lldb/tools/debugserver/source/RNBRemote.cpp b/lldb/tools/debugserver/source/RNBRemote.cpp index ea039101bb541b0..4e9086b0411f2d7 100644 --- a/lldb/tools/debugserver/source/RNBRemote.cpp +++ b/lldb/tools/debugserver/source/RNBRemote.cpp @@ -777,26 +777,28 @@ rnb_err_t RNBRemote::GetPacketPayload(std::string &return_packet) { // DNBLogThreadedIf (LOG_RNB_MAX, "%8u RNBRemote::%s called", // (uint32_t)m_comm.Timer().ElapsedMicroSeconds(true), __FUNCTION__); - PThreadMutex::Locker locker(m_mutex); - if (m_rx_packets.empty()) { - // Only reset the remote command available event if we have no more packets - m_ctx.Events().ResetEvents(RNBContext::event_read_packet_available); - // DNBLogThreadedIf (LOG_RNB_MAX, "%8u RNBRemote::%s error: no packets - // available...", (uint32_t)m_comm.Timer().ElapsedMicroSeconds(true), - // __FUNCTION__); - return rnb_err; - } + { + PThreadMutex::Locker locker(m_mutex); + if (m_rx_packets.empty()) { + // Only reset the remote command available event if we have no more + // packets + m_ctx.Events().ResetEvents(RNBContext::event_read_packet_available); + // DNBLogThreadedIf (LOG_RNB_MAX, "%8u RNBRemote::%s error: no packets + // available...", (uint32_t)m_comm.Timer().ElapsedMicroSeconds(true), + // __FUNCTION__); + return rnb_err; + } - // DNBLogThreadedIf (LOG_RNB_MAX, "%8u RNBRemote::%s has %u queued packets", - // (uint32_t)m_comm.Timer().ElapsedMicroSeconds(true), __FUNCTION__, - // m_rx_packets.size()); - return_packet.swap(m_rx_packets.front()); - m_rx_packets.pop_front(); - locker.Reset(); // Release our lock on the mutex - - if (m_rx_packets.empty()) { - // Reset the remote command available event if we have no more packets - m_ctx.Events().ResetEvents(RNBContext::event_read_packet_available); + // DNBLogThreadedIf (LOG_RNB_MAX, "%8u RNBRemote::%s has %u queued packets", + // (uint32_t)m_comm.Timer().ElapsedMicroSeconds(true), __FUNCTION__, + // m_rx_packets.size()); + return_packet.swap(m_rx_packets.front()); + m_rx_packets.pop_front(); + + if (m_rx_packets.empty()) { + // Reset the remote command available event if we have no more packets + m_ctx.Events().ResetEvents(RNBContext::event_read_packet_available); + } } // DNBLogThreadedIf (LOG_RNB_MEDIUM, "%8u RNBRemote::%s: '%s'", _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
