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[src/trunk]: src/tests/kernel/arch/amd64 Add new tests dbregs_dr[67]_dont_inh...



details:   https://anonhg.NetBSD.org/src/rev/8078e2b9fc4d
branches:  trunk
changeset: 821874:8078e2b9fc4d
user:      kamil <kamil%NetBSD.org@localhost>
date:      Mon Feb 20 06:18:48 2017 +0000

description:
Add new tests dbregs_dr[67]_dont_inherit_lwp in arch/amd64

New tests:
 - dbregs_dr6_dont_inherit_lwp
 - dbregs_dr7_dont_inherit_lwp

Debug Registers are set always per-LWP and they are never inherited.
If a user wants to reuse them, there is need to set trap on thread creation
(PTRACE_LWP_CREATE) and set them from a debugger on newly created LWP.

Sponsored by <The NetBSD Foundation>

diffstat:

 tests/kernel/arch/amd64/t_ptrace_wait.c |  260 +++++++++++++++++++++++++++++++-
 1 files changed, 258 insertions(+), 2 deletions(-)

diffs (288 lines):

diff -r 36023abe4903 -r 8078e2b9fc4d tests/kernel/arch/amd64/t_ptrace_wait.c
--- a/tests/kernel/arch/amd64/t_ptrace_wait.c   Mon Feb 20 05:47:59 2017 +0000
+++ b/tests/kernel/arch/amd64/t_ptrace_wait.c   Mon Feb 20 06:18:48 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: t_ptrace_wait.c,v 1.21 2017/02/20 05:47:59 kamil Exp $ */
+/*     $NetBSD: t_ptrace_wait.c,v 1.22 2017/02/20 06:18:48 kamil Exp $ */
 
 /*-
  * Copyright (c) 2016 The NetBSD Foundation, Inc.
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: t_ptrace_wait.c,v 1.21 2017/02/20 05:47:59 kamil Exp $");
+__RCSID("$NetBSD: t_ptrace_wait.c,v 1.22 2017/02/20 06:18:48 kamil Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -6412,6 +6412,260 @@
        TWAIT_REQUIRE_FAILURE(ECHILD, wpid = TWAIT_GENERIC(child, &status, 0));
 }
 
+ATF_TC(dbregs_dr6_dont_inherit_lwp);
+ATF_TC_HEAD(dbregs_dr6_dont_inherit_lwp, tc)
+{
+       atf_tc_set_md_var(tc, "descr",
+           "Verify that 1 LWP creation is intercepted by ptrace(2) with "
+           "EVENT_MASK set to PTRACE_LWP_CREATE and Debug Register 6 from "
+           "the forker thread is not inherited");
+}
+
+ATF_TC_BODY(dbregs_dr6_dont_inherit_lwp, tc)
+{
+       const int exitval = 5;
+       const int sigval = SIGSTOP;
+       pid_t child, wpid;
+#if defined(TWAIT_HAVE_STATUS)
+       int status;
+#endif
+       ptrace_state_t state;
+       const int slen = sizeof(state);
+       ptrace_event_t event;
+       const int elen = sizeof(event);
+       ucontext_t uc;
+       lwpid_t lid;
+       static const size_t ssize = 16*1024;
+       void *stack;
+       size_t i;
+       struct dbreg r1;
+       struct dbreg r2;
+
+       printf("Before forking process PID=%d\n", getpid());
+       ATF_REQUIRE((child = fork()) != -1);
+       if (child == 0) {
+               printf("Before calling PT_TRACE_ME from child %d\n", getpid());
+               FORKEE_ASSERT(ptrace(PT_TRACE_ME, 0, NULL, 0) != -1);
+
+               printf("Before raising %s from child\n", strsignal(sigval));
+               FORKEE_ASSERT(raise(sigval) == 0);
+
+               printf("Before allocating memory for stack in child\n");
+               FORKEE_ASSERT((stack = malloc(ssize)) != NULL);
+
+               printf("Before making context for new lwp in child\n");
+               _lwp_makecontext(&uc, lwp_main_func, NULL, NULL, stack, ssize);
+
+               printf("Before creating new in child\n");
+               FORKEE_ASSERT(_lwp_create(&uc, 0, &lid) == 0);
+
+               printf("Before waiting for lwp %d to exit\n", lid);
+               FORKEE_ASSERT(_lwp_wait(lid, NULL) == 0);
+
+               printf("Before verifying that reported %d and running lid %d "
+                   "are the same\n", lid, the_lwp_id);
+               FORKEE_ASSERT_EQ(lid, the_lwp_id);
+
+               printf("Before exiting of the child process\n");
+               _exit(exitval);
+       }
+       printf("Parent process PID=%d, child's PID=%d\n", getpid(), child);
+
+       printf("Before calling %s() for the child\n", TWAIT_FNAME);
+       TWAIT_REQUIRE_SUCCESS(wpid = TWAIT_GENERIC(child, &status, 0), child);
+
+       validate_status_stopped(status, sigval);
+
+       printf("Set empty EVENT_MASK for the child %d\n", child);
+       event.pe_set_event = PTRACE_LWP_CREATE;
+       ATF_REQUIRE(ptrace(PT_SET_EVENT_MASK, child, &event, elen) != -1);
+
+       printf("Call GETDBREGS for the child process (r1)\n");
+       ATF_REQUIRE(ptrace(PT_GETDBREGS, child, &r1, 0) != -1);
+
+       printf("State of the debug registers (r1):\n");
+       for (i = 0; i < __arraycount(r1.dr); i++)
+               printf("r1[%zu]=%#lx\n", i, r1.dr[i]);
+
+       r1.dr[6] = 1; /* breakpoint condition dr0 detected */
+       printf("Set DR6 (r1.dr[6]) to new value %#lx\n", r1.dr[6]);
+
+       printf("New state of the debug registers (r1):\n");
+       for (i = 0; i < __arraycount(r1.dr); i++)
+               printf("r1[%zu]=%#lx\n", i, r1.dr[i]);
+
+       printf("Call SETDBREGS for the child process (r1)\n");
+       ATF_REQUIRE(ptrace(PT_SETDBREGS, child, &r1, 0) != -1);
+
+       printf("Before resuming the child process where it left off and "
+           "without signal to be sent\n");
+       ATF_REQUIRE(ptrace(PT_CONTINUE, child, (void *)1, 0) != -1);
+
+       printf("Before calling %s() for the child - expected stopped "
+           "SIGTRAP\n", TWAIT_FNAME);
+       TWAIT_REQUIRE_SUCCESS(wpid = TWAIT_GENERIC(child, &status, 0), child);
+
+       validate_status_stopped(status, SIGTRAP);
+
+       ATF_REQUIRE(ptrace(PT_GET_PROCESS_STATE, child, &state, slen) != -1);
+
+       ATF_REQUIRE_EQ(state.pe_report_event, PTRACE_LWP_CREATE);
+
+       lid = state.pe_lwp;
+       printf("Reported PTRACE_LWP_CREATE event with lid %d\n", lid);
+
+       printf("Call GETDBREGS for the child process new lwp (r2)\n");
+       ATF_REQUIRE(ptrace(PT_GETDBREGS, child, &r2, lid) != -1);
+
+       printf("State of the debug registers (r2):\n");
+       for (i = 0; i < __arraycount(r2.dr); i++)
+               printf("r2[%zu]=%#lx\n", i, r2.dr[i]);
+
+       printf("Assert that (r1) and (r2) are not the same\n");
+       ATF_REQUIRE(memcmp(&r1, &r2, sizeof(r1)) != 0);
+
+       printf("Before resuming the child process where it left off and "
+           "without signal to be sent\n");
+       ATF_REQUIRE(ptrace(PT_CONTINUE, child, (void *)1, 0) != -1);
+
+       printf("Before calling %s() for the child - expected exited\n",
+           TWAIT_FNAME);
+       TWAIT_REQUIRE_SUCCESS(wpid = TWAIT_GENERIC(child, &status, 0), child);
+
+       validate_status_exited(status, exitval);
+
+       printf("Before calling %s() for the child - expected no process\n",
+           TWAIT_FNAME);
+       TWAIT_REQUIRE_FAILURE(ECHILD, wpid = TWAIT_GENERIC(child, &status, 0));
+}
+
+ATF_TC(dbregs_dr7_dont_inherit_lwp);
+ATF_TC_HEAD(dbregs_dr7_dont_inherit_lwp, tc)
+{
+       atf_tc_set_md_var(tc, "descr",
+           "Verify that 1 LWP creation is intercepted by ptrace(2) with "
+           "EVENT_MASK set to PTRACE_LWP_CREATE and Debug Register 7 from "
+           "the forker thread is not inherited");
+}
+
+ATF_TC_BODY(dbregs_dr7_dont_inherit_lwp, tc)
+{
+       const int exitval = 5;
+       const int sigval = SIGSTOP;
+       pid_t child, wpid;
+#if defined(TWAIT_HAVE_STATUS)
+       int status;
+#endif
+       ptrace_state_t state;
+       const int slen = sizeof(state);
+       ptrace_event_t event;
+       const int elen = sizeof(event);
+       ucontext_t uc;
+       lwpid_t lid;
+       static const size_t ssize = 16*1024;
+       void *stack;
+       size_t i;
+       struct dbreg r1;
+       struct dbreg r2;
+
+       printf("Before forking process PID=%d\n", getpid());
+       ATF_REQUIRE((child = fork()) != -1);
+       if (child == 0) {
+               printf("Before calling PT_TRACE_ME from child %d\n", getpid());
+               FORKEE_ASSERT(ptrace(PT_TRACE_ME, 0, NULL, 0) != -1);
+
+               printf("Before raising %s from child\n", strsignal(sigval));
+               FORKEE_ASSERT(raise(sigval) == 0);
+
+               printf("Before allocating memory for stack in child\n");
+               FORKEE_ASSERT((stack = malloc(ssize)) != NULL);
+
+               printf("Before making context for new lwp in child\n");
+               _lwp_makecontext(&uc, lwp_main_func, NULL, NULL, stack, ssize);
+
+               printf("Before creating new in child\n");
+               FORKEE_ASSERT(_lwp_create(&uc, 0, &lid) == 0);
+
+               printf("Before waiting for lwp %d to exit\n", lid);
+               FORKEE_ASSERT(_lwp_wait(lid, NULL) == 0);
+
+               printf("Before verifying that reported %d and running lid %d "
+                   "are the same\n", lid, the_lwp_id);
+               FORKEE_ASSERT_EQ(lid, the_lwp_id);
+
+               printf("Before exiting of the child process\n");
+               _exit(exitval);
+       }
+       printf("Parent process PID=%d, child's PID=%d\n", getpid(), child);
+
+       printf("Before calling %s() for the child\n", TWAIT_FNAME);
+       TWAIT_REQUIRE_SUCCESS(wpid = TWAIT_GENERIC(child, &status, 0), child);
+
+       validate_status_stopped(status, sigval);
+
+       printf("Set empty EVENT_MASK for the child %d\n", child);
+       event.pe_set_event = PTRACE_LWP_CREATE;
+       ATF_REQUIRE(ptrace(PT_SET_EVENT_MASK, child, &event, elen) != -1);
+
+       printf("Call GETDBREGS for the child process (r1)\n");
+       ATF_REQUIRE(ptrace(PT_GETDBREGS, child, &r1, 0) != -1);
+
+       printf("State of the debug registers (r1):\n");
+       for (i = 0; i < __arraycount(r1.dr); i++)
+               printf("r1[%zu]=%#lx\n", i, r1.dr[i]);
+
+       r1.dr[7] = __BIT(16); /* break on data writes dr0 */
+       printf("Set DR6 (r1.dr[7]) to new value %#lx\n", r1.dr[7]);
+
+       printf("New state of the debug registers (r1):\n");
+       for (i = 0; i < __arraycount(r1.dr); i++)
+               printf("r1[%zu]=%#lx\n", i, r1.dr[i]);
+
+       printf("Call SETDBREGS for the child process (r1)\n");
+       ATF_REQUIRE(ptrace(PT_SETDBREGS, child, &r1, 0) != -1);
+
+       printf("Before resuming the child process where it left off and "
+           "without signal to be sent\n");
+       ATF_REQUIRE(ptrace(PT_CONTINUE, child, (void *)1, 0) != -1);
+
+       printf("Before calling %s() for the child - expected stopped "
+           "SIGTRAP\n", TWAIT_FNAME);
+       TWAIT_REQUIRE_SUCCESS(wpid = TWAIT_GENERIC(child, &status, 0), child);
+
+       validate_status_stopped(status, SIGTRAP);
+
+       ATF_REQUIRE(ptrace(PT_GET_PROCESS_STATE, child, &state, slen) != -1);
+
+       ATF_REQUIRE_EQ(state.pe_report_event, PTRACE_LWP_CREATE);
+
+       lid = state.pe_lwp;
+       printf("Reported PTRACE_LWP_CREATE event with lid %d\n", lid);
+
+       printf("Call GETDBREGS for the child process new lwp (r2)\n");
+       ATF_REQUIRE(ptrace(PT_GETDBREGS, child, &r2, lid) != -1);
+
+       printf("State of the debug registers (r2):\n");
+       for (i = 0; i < __arraycount(r2.dr); i++)
+               printf("r2[%zu]=%#lx\n", i, r2.dr[i]);
+
+       printf("Assert that (r1) and (r2) are not the same\n");
+       ATF_REQUIRE(memcmp(&r1, &r2, sizeof(r1)) != 0);
+
+       printf("Before resuming the child process where it left off and "
+           "without signal to be sent\n");
+       ATF_REQUIRE(ptrace(PT_CONTINUE, child, (void *)1, 0) != -1);
+
+       printf("Before calling %s() for the child - expected exited\n",
+           TWAIT_FNAME);
+       TWAIT_REQUIRE_SUCCESS(wpid = TWAIT_GENERIC(child, &status, 0), child);
+
+       validate_status_exited(status, exitval);
+
+       printf("Before calling %s() for the child - expected no process\n",
+           TWAIT_FNAME);
+       TWAIT_REQUIRE_FAILURE(ECHILD, wpid = TWAIT_GENERIC(child, &status, 0));
+}
+
 ATF_TP_ADD_TCS(tp)
 {
        setvbuf(stdout, NULL, _IONBF, 0);
@@ -6490,6 +6744,8 @@
        ATF_TP_ADD_TC_HAVE_DBREGS(tp, dbregs_dr1_dont_inherit_lwp);
        ATF_TP_ADD_TC_HAVE_DBREGS(tp, dbregs_dr2_dont_inherit_lwp);
        ATF_TP_ADD_TC_HAVE_DBREGS(tp, dbregs_dr3_dont_inherit_lwp);
+       ATF_TP_ADD_TC_HAVE_DBREGS(tp, dbregs_dr6_dont_inherit_lwp);
+       ATF_TP_ADD_TC_HAVE_DBREGS(tp, dbregs_dr7_dont_inherit_lwp);
 
        return atf_no_error();
 }



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