From faf44a3105670f74095f6552e3cd7b107fbbb6b3 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Fri, 3 Dec 2021 22:10:05 +0000 Subject: [PATCH] gdbserver: Hide and don't detach pending clone children This commit extends the logic added by these two commits from a while ago: #1 7b961964f866 (gdbserver: hide fork child threads from GDB), #2 df5ad102009c (gdb, gdbserver: detach fork child when detaching from fork parent) ... to handle thread clone events, which are very similar to (v)fork events. For #1, we want to hide clone children as well, so just update the comments. For #2, unlike (v)fork children, pending clone children aren't full processes, they're just threads, so don't detach them in handle_detach. linux-low.cc will take care of detaching them along with all other threads of the process, there's nothing special that needs to be done. Reviewed-By: Andrew Burgess Change-Id: I7f5901d07efda576a2522d03e183994e071b8ffc --- gdbserver/linux-low.cc | 5 +++-- gdbserver/linux-low.h | 15 ++++++++++----- gdbserver/server.cc | 12 +++++++----- gdbserver/target.cc | 3 ++- gdbserver/target.h | 16 +++++++++------- 5 files changed, 31 insertions(+), 20 deletions(-) diff --git a/gdbserver/linux-low.cc b/gdbserver/linux-low.cc index 136a8b6c9a1..7a4f8758ae9 100644 --- a/gdbserver/linux-low.cc +++ b/gdbserver/linux-low.cc @@ -6951,9 +6951,10 @@ linux_process_target::thread_pending_parent (thread_info *thread) } thread_info * -linux_process_target::thread_pending_child (thread_info *thread) +linux_process_target::thread_pending_child (thread_info *thread, + target_waitkind *kind) { - lwp_info *child = get_thread_lwp (thread)->pending_child (); + lwp_info *child = get_thread_lwp (thread)->pending_child (kind); if (child == nullptr) return nullptr; diff --git a/gdbserver/linux-low.h b/gdbserver/linux-low.h index 94093dd4ed8..b5ff9391198 100644 --- a/gdbserver/linux-low.h +++ b/gdbserver/linux-low.h @@ -315,7 +315,8 @@ public: #endif thread_info *thread_pending_parent (thread_info *thread) override; - thread_info *thread_pending_child (thread_info *thread) override; + thread_info *thread_pending_child (thread_info *thread, + target_waitkind *kind) override; bool supports_catch_syscall () override; @@ -756,13 +757,15 @@ struct lwp_info const target_waitstatus &ws = this->relative->waitstatus; gdb_assert (ws.kind () == TARGET_WAITKIND_FORKED - || ws.kind () == TARGET_WAITKIND_VFORKED); + || ws.kind () == TARGET_WAITKIND_VFORKED + || ws.kind () == TARGET_WAITKIND_THREAD_CLONED); return this->relative; } /* If this LWP is the parent of a fork/vfork/clone child we haven't - reported to GDB yet, return that child, else nullptr. */ - lwp_info *pending_child () const + reported to GDB yet, return that child and fill in KIND with the + matching waitkind, otherwise nullptr. */ + lwp_info *pending_child (target_waitkind *kind) const { if (this->relative == nullptr) return nullptr; @@ -781,8 +784,10 @@ struct lwp_info const target_waitstatus &ws = this->waitstatus; gdb_assert (ws.kind () == TARGET_WAITKIND_FORKED - || ws.kind () == TARGET_WAITKIND_VFORKED); + || ws.kind () == TARGET_WAITKIND_VFORKED + || ws.kind () == TARGET_WAITKIND_THREAD_CLONED); + *kind = ws.kind (); return this->relative; } diff --git a/gdbserver/server.cc b/gdbserver/server.cc index c24a5c9fb96..2a70ca63cbd 100644 --- a/gdbserver/server.cc +++ b/gdbserver/server.cc @@ -1349,8 +1349,9 @@ handle_detach (char *own_buf) continue; /* Only threads that have a pending fork event. */ - thread_info *child = target_thread_pending_child (thread); - if (child == nullptr) + target_waitkind kind; + thread_info *child = target_thread_pending_child (thread, &kind); + if (child == nullptr || kind == TARGET_WAITKIND_THREAD_CLONED) continue; process_info *fork_child_process = get_thread_process (child); @@ -1771,9 +1772,10 @@ handle_qxfer_threads_worker (thread_info *thread, std::string *buffer) gdb_byte *handle; bool handle_status = target_thread_handle (ptid, &handle, &handle_len); - /* If this is a fork or vfork child (has a fork parent), GDB does not yet - know about this process, and must not know about it until it gets the - corresponding (v)fork event. Exclude this thread from the list. */ + /* If this is a (v)fork/clone child (has a (v)fork/clone parent), + GDB does not yet know about this thread, and must not know about + it until it gets the corresponding (v)fork/clone event. Exclude + this thread from the list. */ if (target_thread_pending_parent (thread) != nullptr) return; diff --git a/gdbserver/target.cc b/gdbserver/target.cc index 1c740bbf583..dbb4e2d9024 100644 --- a/gdbserver/target.cc +++ b/gdbserver/target.cc @@ -816,7 +816,8 @@ process_stratum_target::thread_pending_parent (thread_info *thread) } thread_info * -process_stratum_target::thread_pending_child (thread_info *thread) +process_stratum_target::thread_pending_child (thread_info *thread, + target_waitkind *kind) { return nullptr; } diff --git a/gdbserver/target.h b/gdbserver/target.h index 8893e0a6a8b..0f1fd5906fb 100644 --- a/gdbserver/target.h +++ b/gdbserver/target.h @@ -478,13 +478,15 @@ public: virtual bool thread_handle (ptid_t ptid, gdb_byte **handle, int *handle_len); - /* If THREAD is a fork child that was not reported to GDB, return its parent - else nullptr. */ + /* If THREAD is a fork/vfork/clone child that was not reported to + GDB, return its parent else nullptr. */ virtual thread_info *thread_pending_parent (thread_info *thread); - /* If THREAD is the parent of a fork child that was not reported to GDB, - return this child, else nullptr. */ - virtual thread_info *thread_pending_child (thread_info *thread); + /* If THREAD is the parent of a fork/vfork/clone child that was not + reported to GDB, return this child and fill in KIND with the + matching waitkind, otherwise nullptr. */ + virtual thread_info *thread_pending_child (thread_info *thread, + target_waitkind *kind); /* Returns true if the target can software single step. */ virtual bool supports_software_single_step (); @@ -700,9 +702,9 @@ target_thread_pending_parent (thread_info *thread) } static inline thread_info * -target_thread_pending_child (thread_info *thread) +target_thread_pending_child (thread_info *thread, target_waitkind *kind) { - return the_target->thread_pending_child (thread); + return the_target->thread_pending_child (thread, kind); } /* Read LEN bytes from MEMADDR in the buffer MYADDR. Return 0 if the read -- 2.30.2