From 75c6c844d9df37761e0e834df057b89e41816e55 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Fri, 10 Jan 2020 20:05:54 +0000 Subject: [PATCH] Fix reconnecting to a gdbserver already debugging multiple processes, II Another bug exposed by gdb.server/extended-remote-restart.exp in the multi-target work is that remote_target::start_remote can leave inferior_ptid and current_inferior() out of sync: (top-gdb) p current_inferior_->pid $1 = 29541 (top-gdb) p inferior_ptid $2 = {m_pid = 29540, m_lwp = 29540, m_tid = 0} This is caused by writing to inferior_ptid directly instead of using switch_to_thread. Also, "inferior_list->thread_list->ptid" assumes that we want the first thread of the first inferior, but that inferior may not have threads, or with multi-target, that target may be connected to some other target. gdb/ChangeLog: 2020-01-10 Pedro Alves * remote.c (remote_target::start_remote): Don't set inferior_ptid directly. Instead find the first thread in the thread list and use switch_to_thread. --- gdb/ChangeLog | 6 ++++++ gdb/remote.c | 12 +++++++++--- 2 files changed, 15 insertions(+), 3 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 4163c869afe..a6fd8b11cd2 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2020-01-10 Pedro Alves + + * remote.c (remote_target::start_remote): Don't set inferior_ptid + directly. Instead find the first thread in the thread list and + use switch_to_thread. + 2020-01-10 Pedro Alves * remote.c (remote_target::remote_add_inferior): Don't bind a diff --git a/gdb/remote.c b/gdb/remote.c index 751769ea7fc..f017f4a719c 100644 --- a/gdb/remote.c +++ b/gdb/remote.c @@ -4701,8 +4701,8 @@ remote_target::start_remote (int from_tty, int extended_p) says should be current. If we're reconnecting to a multi-threaded program, this will ideally be the thread that last reported an event before GDB disconnected. */ - inferior_ptid = get_current_thread (wait_status); - if (inferior_ptid == null_ptid) + ptid_t curr_thread = get_current_thread (wait_status); + if (curr_thread == null_ptid) { /* Odd... The target was able to list threads, but not tell us which thread was current (no "thread" @@ -4714,8 +4714,14 @@ remote_target::start_remote (int from_tty, int extended_p) "warning: couldn't determine remote " "current thread; picking first in list.\n"); - inferior_ptid = inferior_list->thread_list->ptid; + for (thread_info *tp : all_non_exited_threads ()) + { + switch_to_thread (tp); + break; + } } + else + switch_to_thread (find_thread_ptid (curr_thread)); } /* init_wait_for_inferior should be called before get_offsets in order -- 2.30.2