Date: Fri, 22 May 2015 11:04:54 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r283282 - in head: sys/kern tests/sys/kern Message-ID: <201505221104.t4MB4stc054974@svn.freebsd.org>
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Author: jhb Date: Fri May 22 11:04:54 2015 New Revision: 283282 URL: https://svnweb.freebsd.org/changeset/base/283282 Log: Only reparent a traced process to its old parent if the tracing process is not the old parent. Otherwise, proc_reap() will leave the zombie in place resulting in the process' status being returned twice to its parent. Add test cases for PT_TRACE_ME and PT_ATTACH which are fixed by this change. Differential Revision: https://reviews.freebsd.org/D2594 Reviewed by: kib MFC after: 2 weeks Added: head/tests/sys/kern/ptrace_test.c (contents, props changed) Modified: head/sys/kern/kern_exit.c head/tests/sys/kern/Makefile Modified: head/sys/kern/kern_exit.c ============================================================================== --- head/sys/kern/kern_exit.c Fri May 22 11:03:51 2015 (r283281) +++ head/sys/kern/kern_exit.c Fri May 22 11:04:54 2015 (r283282) @@ -847,13 +847,13 @@ proc_reap(struct thread *td, struct proc PROC_LOCK(q); sigqueue_take(p->p_ksi); PROC_UNLOCK(q); - PROC_UNLOCK(p); /* * If we got the child via a ptrace 'attach', we need to give it back * to the old parent. */ - if (p->p_oppid != 0) { + if (p->p_oppid != 0 && p->p_oppid != p->p_pptr->p_pid) { + PROC_UNLOCK(p); t = proc_realparent(p); PROC_LOCK(t); PROC_LOCK(p); @@ -867,6 +867,8 @@ proc_reap(struct thread *td, struct proc sx_xunlock(&proctree_lock); return; } + p->p_oppid = 0; + PROC_UNLOCK(p); /* * Remove other references to this process to ensure we have an Modified: head/tests/sys/kern/Makefile ============================================================================== --- head/tests/sys/kern/Makefile Fri May 22 11:03:51 2015 (r283281) +++ head/tests/sys/kern/Makefile Fri May 22 11:04:54 2015 (r283282) @@ -3,6 +3,7 @@ TESTSDIR= ${TESTSBASE}/sys/kern ATF_TESTS_C+= kern_descrip_test +ATF_TESTS_C+= ptrace_test ATF_TESTS_C+= unix_seqpacket_test TEST_METADATA.unix_seqpacket_test+= timeout="15" Added: head/tests/sys/kern/ptrace_test.c ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ head/tests/sys/kern/ptrace_test.c Fri May 22 11:04:54 2015 (r283282) @@ -0,0 +1,143 @@ +/*- + * Copyright (c) 2015 John Baldwin <jhb@FreeBSD.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/types.h> +#include <sys/ptrace.h> +#include <sys/wait.h> +#include <errno.h> +#include <signal.h> +#include <stdlib.h> +#include <unistd.h> +#include <atf-c.h> + +/* + * Verify that a parent debugger process "sees" the exit of a debugged + * process exactly once when attached via PT_TRACE_ME. + */ +ATF_TC_WITHOUT_HEAD(ptrace__parent_wait_after_trace_me); +ATF_TC_BODY(ptrace__parent_wait_after_trace_me, tc) +{ + pid_t child, wpid; + int status; + + ATF_REQUIRE((child = fork()) != -1); + if (child == 0) { + /* Child process. */ + ATF_REQUIRE(ptrace(PT_TRACE_ME, 0, NULL, 0) != -1); + + /* Trigger a stop. */ + raise(SIGSTOP); + + exit(1); + } + + /* Parent process. */ + + /* The first wait() should report the stop from SIGSTOP. */ + wpid = waitpid(child, &status, 0); + ATF_REQUIRE(wpid == child); + ATF_REQUIRE(WIFSTOPPED(status)); + ATF_REQUIRE(WSTOPSIG(status) == SIGSTOP); + + /* Continue the child ignoring the SIGSTOP. */ + ATF_REQUIRE(ptrace(PT_CONTINUE, child, (caddr_t)1, 0) != -1); + + /* The second wait() should report the exit status. */ + wpid = waitpid(child, &status, 0); + ATF_REQUIRE(wpid == child); + ATF_REQUIRE(WIFEXITED(status)); + ATF_REQUIRE(WEXITSTATUS(status) == 1); + + /* The child should no longer exist. */ + wpid = waitpid(child, &status, 0); + ATF_REQUIRE(wpid == -1); + ATF_REQUIRE(errno == ECHILD); +} + +/* + * Verify that a parent debugger process "sees" the exit of a debugged + * process exactly once when attached via PT_ATTACH. + */ +ATF_TC_WITHOUT_HEAD(ptrace__parent_wait_after_attach); +ATF_TC_BODY(ptrace__parent_wait_after_attach, tc) +{ + pid_t child, wpid; + int cpipe[2], status; + char c; + + ATF_REQUIRE(pipe(cpipe) == 0); + ATF_REQUIRE((child = fork()) != -1); + if (child == 0) { + /* Child process. */ + close(cpipe[0]); + + /* Wait for the parent to attach. */ + ATF_REQUIRE(read(cpipe[1], &c, sizeof(c)) == 0); + + exit(1); + } + close(cpipe[1]); + + /* Parent process. */ + + /* Attach to the child process. */ + ATF_REQUIRE(ptrace(PT_ATTACH, child, NULL, 0) == 0); + + /* The first wait() should report the SIGSTOP from PT_ATTACH. */ + wpid = waitpid(child, &status, 0); + ATF_REQUIRE(wpid == child); + ATF_REQUIRE(WIFSTOPPED(status)); + ATF_REQUIRE(WSTOPSIG(status) == SIGSTOP); + + /* Continue the child ignoring the SIGSTOP. */ + ATF_REQUIRE(ptrace(PT_CONTINUE, child, (caddr_t)1, 0) != -1); + + /* Signal the child to exit. */ + close(cpipe[0]); + + /* The second wait() should report the exit status. */ + wpid = waitpid(child, &status, 0); + ATF_REQUIRE(wpid == child); + ATF_REQUIRE(WIFEXITED(status)); + ATF_REQUIRE(WEXITSTATUS(status) == 1); + + /* The child should no longer exist. */ + wpid = waitpid(child, &status, 0); + ATF_REQUIRE(wpid == -1); + ATF_REQUIRE(errno == ECHILD); +} + +ATF_TP_ADD_TCS(tp) +{ + + ATF_TP_ADD_TC(tp, ptrace__parent_wait_after_trace_me); + ATF_TP_ADD_TC(tp, ptrace__parent_wait_after_attach); + + return (atf_no_error()); +}
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