From ee3c5f8968e7b43854204898fa46933b3a1b5991 Mon Sep 17 00:00:00 2001 From: Philippe Waroquiers Date: Sat, 13 Apr 2019 10:22:41 +0200 Subject: [PATCH] Fix GDB crash when registers cannot be modified. This crash was detected when using GDB with the valgrind gdbserver. To reproduce: valgrind sleep 10000 In another window: gdb target remote | vgdb p printf("make sleep print something\n") => terminate called after throwing an instance of 'gdb_exception_error' Aborted The problem is that the valgrind gdbserver does not allow to change registers when the inferior is blocked in a system call. GDB then raises an exception. The exception causes the destructor of typedef std::unique_ptr infcall_suspend_state_up; to be called. This destructor itself tries to restore the value of the registers, and fails similarly. We must catch the exception in the destructor to avoid crashing GDB. If the destructor encounters a problem, no warning is produced if there is an uncaught exception, as in this case, the user will already be informed of a problem via this exception. With this change, no crash anymore, and all the valgrind 3.15 tests pass succesfully. gdb/ChangeLog 2019-04-19 Philippe Waroquiers * inferior.h (struct infcall_suspend_state_deleter): Catch exception in destructor to avoid crash. --- gdb/inferior.h | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/gdb/inferior.h b/gdb/inferior.h index f98e67d..9e0e3b3 100644 --- a/gdb/inferior.h +++ b/gdb/inferior.h @@ -68,7 +68,18 @@ struct infcall_suspend_state_deleter { void operator() (struct infcall_suspend_state *state) const { - restore_infcall_suspend_state (state); + try + { + restore_infcall_suspend_state (state); + } + catch (const gdb_exception_error &e) + { + /* If we are restoring the inferior state due to an exception, + some error message will be printed. So, only warn the user + when we cannot restore during normal execution. */ + if (!std::uncaught_exception ()) + warning (_("Failed to restore inferior state: %s"), e.what ()); + } } }; -- 2.7.4