clayborg created this revision. We use GDBRemoteCommunication::ScopedTimeout in many places to change the packet timeout that is used for individual packets. If someone modifies the default timeout manually or the GDB remote server requests a longer timeout in a 'q' packet, then don't ever reduce a timeout for a packet since that could make things fail.
This patch checks the timeout to ensure the new timeout is larger before it modifies the timeout. The GDBRemoteCommunication::ScopedTimeout object also remembers if it did update the timeout and will restore the old timeout only if it did. https://reviews.llvm.org/D32087 Files: source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h Index: source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h =================================================================== --- source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h +++ source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h @@ -89,6 +89,10 @@ private: GDBRemoteCommunication &m_gdb_comm; std::chrono::seconds m_saved_timeout; + // Don't ever reduce the timeout for a packet, only increase it. If the + // requested timeout if less than the current timeout, we don't set it + // and won't need to restore it. + bool m_timeout_modified; }; GDBRemoteCommunication(const char *comm_name, const char *listener_name); Index: source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp =================================================================== --- source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp +++ source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp @@ -1310,12 +1310,20 @@ GDBRemoteCommunication::ScopedTimeout::ScopedTimeout( GDBRemoteCommunication &gdb_comm, std::chrono::seconds timeout) - : m_gdb_comm(gdb_comm) { - m_saved_timeout = m_gdb_comm.SetPacketTimeout(timeout); + : m_gdb_comm(gdb_comm), m_timeout_modified(false) { + auto curr_timeout = gdb_comm.GetPacketTimeout(); + // Only update the timeout if the timeout is greater than the current + // timeout. If the current timeout is larger, then just use that. + if (curr_timeout < timeout) { + m_timeout_modified = true; + m_saved_timeout = m_gdb_comm.SetPacketTimeout(timeout); + } } GDBRemoteCommunication::ScopedTimeout::~ScopedTimeout() { - m_gdb_comm.SetPacketTimeout(m_saved_timeout); + // Only restore the timeout if we set it in the constructor. + if (m_timeout_modified) + m_gdb_comm.SetPacketTimeout(m_saved_timeout); } // This function is called via the Communications class read thread when bytes
Index: source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h =================================================================== --- source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h +++ source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h @@ -89,6 +89,10 @@ private: GDBRemoteCommunication &m_gdb_comm; std::chrono::seconds m_saved_timeout; + // Don't ever reduce the timeout for a packet, only increase it. If the + // requested timeout if less than the current timeout, we don't set it + // and won't need to restore it. + bool m_timeout_modified; }; GDBRemoteCommunication(const char *comm_name, const char *listener_name); Index: source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp =================================================================== --- source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp +++ source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp @@ -1310,12 +1310,20 @@ GDBRemoteCommunication::ScopedTimeout::ScopedTimeout( GDBRemoteCommunication &gdb_comm, std::chrono::seconds timeout) - : m_gdb_comm(gdb_comm) { - m_saved_timeout = m_gdb_comm.SetPacketTimeout(timeout); + : m_gdb_comm(gdb_comm), m_timeout_modified(false) { + auto curr_timeout = gdb_comm.GetPacketTimeout(); + // Only update the timeout if the timeout is greater than the current + // timeout. If the current timeout is larger, then just use that. + if (curr_timeout < timeout) { + m_timeout_modified = true; + m_saved_timeout = m_gdb_comm.SetPacketTimeout(timeout); + } } GDBRemoteCommunication::ScopedTimeout::~ScopedTimeout() { - m_gdb_comm.SetPacketTimeout(m_saved_timeout); + // Only restore the timeout if we set it in the constructor. + if (m_timeout_modified) + m_gdb_comm.SetPacketTimeout(m_saved_timeout); } // This function is called via the Communications class read thread when bytes
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