Index: source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp =================================================================== --- source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp +++ source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp @@ -2729,16 +2729,19 @@ size_t ProcessGDBRemote::DoReadMemory(addr_t addr, void *buf, size_t size, Error &error) { GetMaxMemorySize(); - if (size > m_max_memory_size) { + bool binary_memory_read = m_gdb_comm.GetxPacketSupported(); + // M and m packets take 2 bytes for 1 byte of memory + size_t max_memory_size = + binary_memory_read ? m_max_memory_size : m_max_memory_size / 2; + if (size > max_memory_size) { // Keep memory read sizes down to a sane limit. This function will be // called multiple times in order to complete the task by // lldb_private::Process so it is ok to do this. - size = m_max_memory_size; + size = max_memory_size; } char packet[64]; int packet_len; - bool binary_memory_read = m_gdb_comm.GetxPacketSupported(); packet_len = ::snprintf(packet, sizeof(packet), "%c%" PRIx64 ",%" PRIx64, binary_memory_read ? 'x' : 'm', (uint64_t)addr, (uint64_t)size); @@ -2785,11 +2788,13 @@ size_t ProcessGDBRemote::DoWriteMemory(addr_t addr, const void *buf, size_t size, Error &error) { GetMaxMemorySize(); - if (size > m_max_memory_size) { + // M and m packets take 2 bytes for 1 byte of memory + size_t max_memory_size = m_max_memory_size / 2; + if (size > max_memory_size) { // Keep memory read sizes down to a sane limit. This function will be // called multiple times in order to complete the task by // lldb_private::Process so it is ok to do this. - size = m_max_memory_size; + size = max_memory_size; } StreamString packet; @@ -3988,6 +3993,20 @@ stub_max_size = reasonable_largeish_default; } + // Memory packet have other overheads too like Maddr,size:#NN + // Instead of calculating the bytes taken by size and addr every + // time, we take a maximum guess here. + if (stub_max_size > 70) + stub_max_size -= 32 + 32 + 6; + else { + // In unlikely scenario that max packet size is less then 70, we will + // hope that data being written is small enough to fit. + Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS)); + if (log) + log->Warning("Packet size is too small." + "LLDB may face problems while writing memory"); + } + m_max_memory_size = stub_max_size; } else { m_max_memory_size = conservative_default;