diff options
| -rw-r--r-- | sys/kern/kern_sig.c | 19 | ||||
| -rw-r--r-- | tests/sys/kern/ptrace_test.c | 210 |
2 files changed, 219 insertions, 10 deletions
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c index d6aec28..b88bcd4 100644 --- a/sys/kern/kern_sig.c +++ b/sys/kern/kern_sig.c @@ -2197,11 +2197,9 @@ tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi) if (action == SIG_HOLD && !((prop & SA_CONT) && (p->p_flag & P_STOPPED_SIG))) return (ret); - /* - * SIGKILL: Remove procfs STOPEVENTs and ptrace events. - */ + + /* SIGKILL: Remove procfs STOPEVENTs. */ if (sig == SIGKILL) { - p->p_ptevents = 0; /* from procfs_ioctl.c: PIOCBIC */ p->p_stops = 0; /* from procfs_ioctl.c: PIOCCONT */ @@ -2824,14 +2822,15 @@ issignal(struct thread *td) break; /* == ignore */ } /* - * If there is a pending stop signal to process - * with default action, stop here, - * then clear the signal. However, - * if process is member of an orphaned - * process group, ignore tty stop signals. + * If there is a pending stop signal to process with + * default action, stop here, then clear the signal. + * Traced or exiting processes should ignore stops. + * Additionally, a member of an orphaned process group + * should ignore tty stops. */ if (prop & SA_STOP) { - if (p->p_flag & (P_TRACED|P_WEXIT) || + if (p->p_flag & + (P_TRACED | P_WEXIT | P_SINGLE_EXIT) || (p->p_pgrp->pg_jobc == 0 && prop & SA_TTYSTOP)) break; /* == ignore */ diff --git a/tests/sys/kern/ptrace_test.c b/tests/sys/kern/ptrace_test.c index d847b22..03a7412 100644 --- a/tests/sys/kern/ptrace_test.c +++ b/tests/sys/kern/ptrace_test.c @@ -31,6 +31,7 @@ __FBSDID("$FreeBSD$"); #include <sys/cpuset.h> #include <sys/event.h> #include <sys/time.h> +#include <sys/procctl.h> #include <sys/ptrace.h> #include <sys/queue.h> #include <sys/runq.h> @@ -2732,6 +2733,212 @@ ATF_TC_BODY(ptrace__PT_CONTINUE_with_signal_thread_sigmask, tc) ATF_REQUIRE(errno == ECHILD); } +static void * +raise_sigstop_thread(void *arg __unused) +{ + + raise(SIGSTOP); + return NULL; +} + +static void * +sleep_thread(void *arg __unused) +{ + + sleep(60); + return NULL; +} + +static void +terminate_with_pending_sigstop(bool sigstop_from_main_thread) +{ + pid_t fpid, wpid; + int status, i; + cpuset_t setmask; + cpusetid_t setid; + pthread_t t; + + /* + * Become the reaper for this process tree. We need to be able to check + * that both child and grandchild have died. + */ + ATF_REQUIRE(procctl(P_PID, getpid(), PROC_REAP_ACQUIRE, NULL) == 0); + + fpid = fork(); + ATF_REQUIRE(fpid >= 0); + if (fpid == 0) { + fpid = fork(); + CHILD_REQUIRE(fpid >= 0); + if (fpid == 0) { + trace_me(); + + /* Pin to CPU 0 to serialize thread execution. */ + CPU_ZERO(&setmask); + CPU_SET(0, &setmask); + CHILD_REQUIRE(cpuset(&setid) == 0); + CHILD_REQUIRE(cpuset_setaffinity(CPU_LEVEL_CPUSET, + CPU_WHICH_CPUSET, setid, + sizeof(setmask), &setmask) == 0); + + if (sigstop_from_main_thread) { + /* + * We expect the SIGKILL sent when our parent + * dies to be delivered to the new thread. + * Raise the SIGSTOP in this thread so the + * threads compete. + */ + CHILD_REQUIRE(pthread_create(&t, NULL, + sleep_thread, NULL) == 0); + raise(SIGSTOP); + } else { + /* + * We expect the SIGKILL to be delivered to + * this thread. After creating the new thread, + * just get off the CPU so the other thread can + * raise the SIGSTOP. + */ + CHILD_REQUIRE(pthread_create(&t, NULL, + raise_sigstop_thread, NULL) == 0); + sleep(60); + } + + exit(0); + } + /* First stop is trace_me() immediately after fork. */ + wpid = waitpid(fpid, &status, 0); + CHILD_REQUIRE(wpid == fpid); + CHILD_REQUIRE(WIFSTOPPED(status)); + CHILD_REQUIRE(WSTOPSIG(status) == SIGSTOP); + + CHILD_REQUIRE(ptrace(PT_CONTINUE, fpid, (caddr_t)1, 0) == 0); + + /* Second stop is from the raise(SIGSTOP). */ + wpid = waitpid(fpid, &status, 0); + CHILD_REQUIRE(wpid == fpid); + CHILD_REQUIRE(WIFSTOPPED(status)); + CHILD_REQUIRE(WSTOPSIG(status) == SIGSTOP); + + /* + * Terminate tracing process without detaching. Our child + * should be killed. + */ + exit(0); + } + + /* + * We should get a normal exit from our immediate child and a SIGKILL + * exit from our grandchild. The latter case is the interesting one. + * Our grandchild should not have stopped due to the SIGSTOP that was + * left dangling when its parent died. + */ + for (i = 0; i < 2; ++i) { + wpid = wait(&status); + if (wpid == fpid) + ATF_REQUIRE(WIFEXITED(status) && + WEXITSTATUS(status) == 0); + else + ATF_REQUIRE(WIFSIGNALED(status) && + WTERMSIG(status) == SIGKILL); + } +} + +/* + * These two tests ensure that if the tracing process exits without detaching + * just after the child received a SIGSTOP, the child is cleanly killed and + * doesn't go to sleep due to the SIGSTOP. The parent's death will send a + * SIGKILL to the child. If the SIGKILL and the SIGSTOP are handled by + * different threads, the SIGKILL must win. There are two variants of this + * test, designed to catch the case where the SIGKILL is delivered to the + * younger thread (the first test) and the case where the SIGKILL is delivered + * to the older thread (the second test). This behavior has changed in the + * past, so make no assumption. + */ +ATF_TC_WITHOUT_HEAD(ptrace__parent_terminate_with_pending_sigstop1); +ATF_TC_BODY(ptrace__parent_terminate_with_pending_sigstop1, tc) +{ + + terminate_with_pending_sigstop(true); +} +ATF_TC_WITHOUT_HEAD(ptrace__parent_terminate_with_pending_sigstop2); +ATF_TC_BODY(ptrace__parent_terminate_with_pending_sigstop2, tc) +{ + + terminate_with_pending_sigstop(false); +} + +/* + * Verify that after ptrace() discards a SIGKILL signal, the event mask + * is not modified. + */ +ATF_TC_WITHOUT_HEAD(ptrace__event_mask_sigkill_discard); +ATF_TC_BODY(ptrace__event_mask_sigkill_discard, tc) +{ + struct ptrace_lwpinfo pl; + pid_t fpid, wpid; + int status, event_mask, new_event_mask; + + ATF_REQUIRE((fpid = fork()) != -1); + if (fpid == 0) { + trace_me(); + raise(SIGSTOP); + exit(0); + } + + /* The first wait() should report the stop from trace_me(). */ + wpid = waitpid(fpid, &status, 0); + ATF_REQUIRE(wpid == fpid); + ATF_REQUIRE(WIFSTOPPED(status)); + ATF_REQUIRE(WSTOPSIG(status) == SIGSTOP); + + /* Set several unobtrusive event bits. */ + event_mask = PTRACE_EXEC | PTRACE_FORK | PTRACE_LWP; + ATF_REQUIRE(ptrace(PT_SET_EVENT_MASK, wpid, (caddr_t)&event_mask, + sizeof(event_mask)) == 0); + + /* Send a SIGKILL without using ptrace. */ + ATF_REQUIRE(kill(fpid, SIGKILL) == 0); + + /* Continue the child ignoring the SIGSTOP. */ + ATF_REQUIRE(ptrace(PT_CONTINUE, fpid, (caddr_t)1, 0) == 0); + + /* The next stop should be due to the SIGKILL. */ + wpid = waitpid(fpid, &status, 0); + ATF_REQUIRE(wpid == fpid); + ATF_REQUIRE(WIFSTOPPED(status)); + ATF_REQUIRE(WSTOPSIG(status) == SIGKILL); + + ATF_REQUIRE(ptrace(PT_LWPINFO, wpid, (caddr_t)&pl, sizeof(pl)) != -1); + ATF_REQUIRE(pl.pl_flags & PL_FLAG_SI); + ATF_REQUIRE(pl.pl_siginfo.si_signo == SIGKILL); + + /* Continue the child ignoring the SIGKILL. */ + ATF_REQUIRE(ptrace(PT_CONTINUE, fpid, (caddr_t)1, 0) == 0); + + /* The next wait() should report the stop from SIGSTOP. */ + wpid = waitpid(fpid, &status, 0); + ATF_REQUIRE(wpid == fpid); + ATF_REQUIRE(WIFSTOPPED(status)); + ATF_REQUIRE(WSTOPSIG(status) == SIGSTOP); + + /* Check the current event mask. It should not have changed. */ + new_event_mask = 0; + ATF_REQUIRE(ptrace(PT_GET_EVENT_MASK, wpid, (caddr_t)&new_event_mask, + sizeof(new_event_mask)) == 0); + ATF_REQUIRE(event_mask == new_event_mask); + + /* Continue the child to let it exit. */ + ATF_REQUIRE(ptrace(PT_CONTINUE, fpid, (caddr_t)1, 0) == 0); + + /* The last event should be for the child process's exit. */ + wpid = waitpid(fpid, &status, 0); + ATF_REQUIRE(WIFEXITED(status)); + ATF_REQUIRE(WEXITSTATUS(status) == 0); + + wpid = wait(&status); + ATF_REQUIRE(wpid == -1); + ATF_REQUIRE(errno == ECHILD); +} + ATF_TP_ADD_TCS(tp) { @@ -2775,6 +2982,9 @@ ATF_TP_ADD_TCS(tp) ATF_TP_ADD_TC(tp, ptrace__PT_CONTINUE_with_signal_mix); ATF_TP_ADD_TC(tp, ptrace__PT_CONTINUE_with_signal_kqueue); ATF_TP_ADD_TC(tp, ptrace__PT_CONTINUE_with_signal_thread_sigmask); + ATF_TP_ADD_TC(tp, ptrace__parent_terminate_with_pending_sigstop1); + ATF_TP_ADD_TC(tp, ptrace__parent_terminate_with_pending_sigstop2); + ATF_TP_ADD_TC(tp, ptrace__event_mask_sigkill_discard); return (atf_no_error()); } |
