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author | Pedro Alves <pedro@palves.net> | 2022-06-27 20:41:50 +0100 |
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committer | Pedro Alves <pedro@palves.net> | 2022-06-28 18:11:29 +0100 |
commit | a9deee17d33235eeba401eebed55c85a742e3358 (patch) | |
tree | 3dbd67fe9ee0566ceab74a4692c7abf42ce7fc60 /gdbserver/fork-child.cc | |
parent | 9117c7b452ef76304f4394a97c887d0c4af439f5 (diff) | |
download | binutils-a9deee17d33235eeba401eebed55c85a742e3358.zip binutils-a9deee17d33235eeba401eebed55c85a742e3358.tar.gz binutils-a9deee17d33235eeba401eebed55c85a742e3358.tar.bz2 |
gdb+gdbserver/Linux: avoid reading registers while going through shell
For every stop, Linux GDB and GDBserver save the stopped thread's PC,
in lwp->stop_pc. This is done in save_stop_reason, in both
gdb/linux-nat.c and gdbserver/linux-low.cc. However, while we're
going through the shell after "run", in startup_inferior, we shouldn't
be reading registers, as we haven't yet determined the target's
architecture -- the shell's architecture may not even be the same as
the final inferior's.
In gdb/linux-nat.c, lwp->stop_pc is only needed when the thread has
stopped for a breakpoint, and since when going through the shell, no
breakpoint is going to hit, we could simply teach save_stop_reason to
only record the stop pc when the thread stopped for a breakpoint.
However, in gdbserver/linux-low.cc, lwp->stop_pc is used in more cases
than breakpoint hits (e.g., it's used in tracepoints & the
"while-stepping" feature).
So to avoid GDB vs GDBserver divergence, we apply the same approach to
both implementations.
We set a flag in the inferior (process in GDBserver) whenever it is
being nursed through the shell, and when that flag is set,
save_stop_reason bails out early. While going through the shell,
we'll only ever get process exits (normal or signalled), random
signals, and exec events, so nothing is lost.
Change-Id: If0f01831514d3a74d17efd102875de7d2c6401ad
Diffstat (limited to 'gdbserver/fork-child.cc')
-rw-r--r-- | gdbserver/fork-child.cc | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/gdbserver/fork-child.cc b/gdbserver/fork-child.cc index 96dd4d0..7ea66f2 100644 --- a/gdbserver/fork-child.cc +++ b/gdbserver/fork-child.cc @@ -18,6 +18,7 @@ #include "server.h" #include "gdbsupport/job-control.h" +#include "gdbsupport/scoped_restore.h" #include "nat/fork-inferior.h" #ifdef HAVE_SIGNAL_H #include <signal.h> @@ -103,6 +104,10 @@ post_fork_inferior (int pid, const char *program) atexit (restore_old_foreground_pgrp); #endif + process_info *proc = find_process_pid (pid); + scoped_restore save_starting_up + = make_scoped_restore (&proc->starting_up, true); + startup_inferior (the_target, pid, START_INFERIOR_TRAPS_EXPECTED, &cs.last_status, &cs.last_ptid); |