From 953473375500a809fbb3eca3efa4dbb670c3a32f Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Tue, 3 Jul 2018 19:02:48 +0100 Subject: [PATCH] gdb: Avoid using W_STOPCODE(0) as this is ambiguous on MIPS The MIPS target supports 127 signals, and this can create an ambiguity in process wait statuses. A status value of 0x007f could potentially indicate a process that has exited with signal 127, or a process that has stopped with signal 0. In uClibc-ng the interpretation of 0x007f is that the process has exited with signal 127 rather than stopped with signal 0, and so, WIFSTOPPED (W_STOPCODE (0)) will be false rather than true as it would be on most other platforms. Given that it's pretty easy to avoid using W_STOPCODE (0), lets do that. gdb/ChangeLog: * linux-nat.c (linux_nat_target::follow_fork): Avoid using 'W_STOPCODE (0)' as this could be ambiguous. --- gdb/ChangeLog | 6 ++++++ gdb/linux-nat.c | 15 +++++++++++---- 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 43594561d50..0d38674640e 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2018-08-06 Sergey Korolev + Andrew Burgess + + * linux-nat.c (linux_nat_target::follow_fork): Avoid using + 'W_STOPCODE (0)' as this could be ambiguous. + 2018-08-03 Sergio Durigan Junior * ser-tcp.c (net_open): Fix thinko when deciding whether to diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c index 86d3dfd2b89..d2c88ad0cd4 100644 --- a/gdb/linux-nat.c +++ b/gdb/linux-nat.c @@ -445,7 +445,6 @@ linux_nat_target::follow_fork (int follow_child, int detach_fork) if (!follow_child) { struct lwp_info *child_lp = NULL; - int status = W_STOPCODE (0); int has_vforked; ptid_t parent_ptid, child_ptid; int parent_pid, child_pid; @@ -465,6 +464,8 @@ linux_nat_target::follow_fork (int follow_child, int detach_fork) /* Detach new forked process? */ if (detach_fork) { + int child_stop_signal = 0; + bool detach_child = true; struct cleanup *old_chain = make_cleanup (delete_lwp_cleanup, child_lp); @@ -484,18 +485,24 @@ linux_nat_target::follow_fork (int follow_child, int detach_fork) if (!gdbarch_software_single_step_p (target_thread_architecture (parent_ptid))) { + int status; + linux_disable_event_reporting (child_pid); if (ptrace (PTRACE_SINGLESTEP, child_pid, 0, 0) < 0) perror_with_name (_("Couldn't do single step")); if (my_waitpid (child_pid, &status, 0) < 0) perror_with_name (_("Couldn't wait vfork process")); + else + { + detach_child = WIFSTOPPED (status); + child_stop_signal = WSTOPSIG (status); + } } - if (WIFSTOPPED (status)) + if (detach_child) { - int signo; + int signo = child_stop_signal; - signo = WSTOPSIG (status); if (signo != 0 && !signal_pass_state (gdb_signal_from_host (signo))) signo = 0; -- 2.30.2