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Introduce fixes for ptrace(2) 

Stop disabling LWP create and exit events for PT_SYSCALL tracing.
PT_SYSCALL disabled EXEC reporting for legacy reasons, there is no need
to repeat it for LWP and CHLD events.

Pass full siginfo from trapsignal events (SEGV, BUS, ILL, TRAP, FPE).
This adds missing information about signals like fault address.

Set ps_lwp always.

Before passing siginfo to userland through p_sigctx.ps_info, make sure
that it was zeroed for unused bytes. LWP and CHLD events do not set si_addr
and si_trap, these pieces of information are passed for crashes (like
software breakpoint).

LLDB crash reporting works now correctly:

(lldb) r
Process 552 launched: '/tmp/a.out' (x86_64)
Process 552 stopped
* thread #1, stop reason = signal SIGSEGV: invalid address (fault address: 0x123456)
This commit is contained in:
kamil 2019-05-02 22:23:49 +00:00
parent 143ea479d8
commit ac37cdce0c
3 changed files with 20 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
sys/kern/kern_lwp.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: kern_lwp.c,v 1.198 2019/05/01 21:57:34 kamil Exp $ */
/* $NetBSD: kern_lwp.c,v 1.199 2019/05/02 22:23:49 kamil Exp $ */
/*-
* Copyright (c) 2001, 2006, 2007, 2008, 2009 The NetBSD Foundation, Inc.
@ -211,7 +211,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.198 2019/05/01 21:57:34 kamil Exp $");
__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.199 2019/05/02 22:23:49 kamil Exp $");
#include "opt_ddb.h"
#include "opt_lockdebug.h"
@ -1079,7 +1079,7 @@ lwp_exit(struct lwp *l)
*/
mutex_enter(proc_lock);
if ((p->p_slflag & (PSL_TRACED|PSL_TRACELWP_EXIT|PSL_SYSCALL)) ==
if ((p->p_slflag & (PSL_TRACED|PSL_TRACELWP_EXIT)) ==
(PSL_TRACED|PSL_TRACELWP_EXIT)) {
mutex_enter(p->p_lock);
p->p_lwp_exited = l->l_lid;

16
sys/kern/kern_sig.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: kern_sig.c,v 1.355 2019/05/01 21:52:35 kamil Exp $ */
/* $NetBSD: kern_sig.c,v 1.356 2019/05/02 22:23:49 kamil Exp $ */
/*-
* Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
@ -70,7 +70,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.355 2019/05/01 21:52:35 kamil Exp $");
__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.356 2019/05/02 22:23:49 kamil Exp $");
#include "opt_ptrace.h"
#include "opt_dtrace.h"
@ -913,8 +913,14 @@ trapsignal(struct lwp *l, ksiginfo_t *ksi)
mutex_enter(p->p_lock);
if (ISSET(p->p_slflag, PSL_TRACED) &&
!(p->p_pptr == p->p_opptr && ISSET(p->p_lflag, PL_PPWAIT))) {
eventswitch(signo, ksi->ksi_code);
!(p->p_pptr == p->p_opptr && ISSET(p->p_lflag, PL_PPWAIT)) &&
p->p_xsig != SIGKILL &&
!sigismember(&p->p_sigpend.sp_set, SIGKILL)) {
p->p_xsig = signo;
p->p_sigctx.ps_faked = true;
p->p_sigctx.ps_lwp = ksi->ksi_lid;
p->p_sigctx.ps_info = ksi->ksi_info;
sigswitch(0, signo, false);
// XXX ktrpoint(KTR_PSIG)
mutex_exit(p->p_lock);
return;
@ -1556,6 +1562,8 @@ eventswitch(int signo, int code)
p->p_xsig = signo;
p->p_sigctx.ps_faked = true;
p->p_sigctx.ps_lwp = l->l_lid;
memset(&p->p_sigctx.ps_info, 0, sizeof(p->p_sigctx.ps_info));
p->p_sigctx.ps_info._signo = signo;
p->p_sigctx.ps_info._code = code;

10
sys/kern/sys_lwp.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: sys_lwp.c,v 1.65 2019/05/01 22:55:55 kamil Exp $ */
/* $NetBSD: sys_lwp.c,v 1.66 2019/05/02 22:23:49 kamil Exp $ */
/*-
* Copyright (c) 2001, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@ -35,7 +35,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.65 2019/05/01 22:55:55 kamil Exp $");
__KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.66 2019/05/02 22:23:49 kamil Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@ -78,12 +78,12 @@ mi_startlwp(void *arg)
(p->p_emul->e_startlwp)(arg);
/* If the process is traced, report lwp creation to a debugger */
if ((p->p_slflag & (PSL_TRACED|PSL_TRACELWP_CREATE|PSL_SYSCALL)) ==
if ((p->p_slflag & (PSL_TRACED|PSL_TRACELWP_CREATE)) ==
(PSL_TRACED|PSL_TRACELWP_CREATE)) {
/* Paranoid check */
mutex_enter(proc_lock);
if ((p->p_slflag & (PSL_TRACED|PSL_TRACELWP_CREATE|PSL_SYSCALL)) !=
(PSL_TRACED|PSL_TRACELWP_CREATE)) {
if ((p->p_slflag & (PSL_TRACED|PSL_TRACELWP_CREATE)) !=
(PSL_TRACED|PSL_TRACELWP_CREATE)) {
mutex_exit(proc_lock);
return;
}