Module Name: src
Committed By: kamil
Date: Sat May 16 23:10:26 UTC 2020
Modified Files:
src/tests/lib/libc/sys: t_ptrace_fork_wait.h
Log Message:
Ignore interception of SIGCHLD signals in the debugger
Set SIGPASS for SIGCHLD for the traced child in the following tests:
- unrelated_tracer_fork*
- unrelated_tracer_vfork*
- unrelated_tracer_posix_spawn*
There is a race that SIGCHLD might be blocked during forking and dropped.
PR/55241 by Andreas Gustafsson
To generate a diff of this commit:
cvs rdiff -u -r1.5 -r1.6 src/tests/lib/libc/sys/t_ptrace_fork_wait.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/tests/lib/libc/sys/t_ptrace_fork_wait.h
diff -u src/tests/lib/libc/sys/t_ptrace_fork_wait.h:1.5 src/tests/lib/libc/sys/t_ptrace_fork_wait.h:1.6
--- src/tests/lib/libc/sys/t_ptrace_fork_wait.h:1.5 Sat May 16 22:07:06 2020
+++ src/tests/lib/libc/sys/t_ptrace_fork_wait.h Sat May 16 23:10:26 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: t_ptrace_fork_wait.h,v 1.5 2020/05/16 22:07:06 kamil Exp $ */
+/* $NetBSD: t_ptrace_fork_wait.h,v 1.6 2020/05/16 23:10:26 kamil Exp $ */
/*-
* Copyright (c) 2016, 2017, 2018, 2020 The NetBSD Foundation, Inc.
@@ -337,6 +337,7 @@ unrelated_tracer_fork_body(const char *f
int status;
#endif
+ sigset_t set;
struct ptrace_siginfo info;
ptrace_state_t state;
const int slen = sizeof(state);
@@ -453,6 +454,21 @@ unrelated_tracer_fork_body(const char *f
SYSCALL_REQUIRE(ptrace(PT_SET_EVENT_MASK, tracee, &event, elen)
!= -1);
+ /*
+ * Ignore interception of the SIGCHLD signals.
+ *
+ * SIGCHLD once blocked is discarded by the kernel as it has the
+ * SA_IGNORE property. During the fork(2) operation all signals
+ * can be shortly blocked and missed (unless there is a
+ * registered signal handler in the traced child). This leads to
+ * a race in this test if there would be an intention to catch
+ * SIGCHLD.
+ */
+ sigemptyset(&set);
+ sigaddset(&set, SIGCHLD);
+ SYSCALL_REQUIRE(ptrace(PT_SET_SIGPASS, tracee, &set,
+ sizeof(set)) != -1);
+
DPRINTF("Before resuming the child process where it left off "
"and without signal to be sent\n");
SYSCALL_REQUIRE(ptrace(PT_CONTINUE, tracee, (void *)1, 0) != -1);
@@ -559,16 +575,6 @@ unrelated_tracer_fork_body(const char *f
wpid = TWAIT_GENERIC(tracee2, &status, 0));
}
- DPRINTF("Before calling %s() for the tracee - expected stopped "
- "SIGCHLD\n", TWAIT_FNAME);
- TWAIT_REQUIRE_SUCCESS(wpid = TWAIT_GENERIC(tracee, &status, 0), tracee);
-
- validate_status_stopped(status, SIGCHLD);
-
- DPRINTF("Before resuming the tracee process where it left off and "
- "without signal to be sent\n");
- SYSCALL_REQUIRE(ptrace(PT_CONTINUE, tracee, (void *)1, 0) != -1);
-
DPRINTF("Before calling %s() for the tracee - expected exited\n",
TWAIT_FNAME);
TWAIT_REQUIRE_SUCCESS(wpid = TWAIT_GENERIC(tracee, &status, 0), tracee);
