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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
This commit is contained in:
kamil 2020-05-16 23:10:26 +00:00
parent 9d5d6dbf80
commit 2affbc81a5
1 changed files with 17 additions and 11 deletions
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28
tests/lib/libc/sys/t_ptrace_fork_wait.h
View File

@ -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 *fn, bool trackspawn, bool trackfork,
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 *fn, bool trackspawn, bool trackfork,
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 *fn, bool trackspawn, bool trackfork,
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);