> And p_sigmask is copied during fork, so that needs a bit of thought.
> I guess it doesn't matter for the new child, as it isn't running yet
> and therefore can't invoke sigprocmask(2). And the parent should be
> safe as well, as it is in fork(2) and therefore can't call
> sigprocmask(2) either.
memcpy(p_startcopy) which is, tadaaa, p_sigmask! From implementations
of memcpy I've seen (usage of SSE or non-temporal instructions to begin
with) it seems that no guarantee about how big a chunk does it copy
atomically can be assumed...
So a multithreaded process doing sigprocmask(2) in one thread and
simultaneously fork(2) in the other? Not a problem either, because
1003.1 2004 edition says that sigprocmask(2) is equivalent to
pthread_sigmask(3) and the fork only copies the other thread, not
bothering with the sigprocmask-ing one.
I haven't checked the code that thoroughly but this is what POSIX says.
> There's also a couple of additional p->p_sigmask |= ... in kern_sig.c.
>
> All of these need to become atomic_setbits_int/atomic_clearbits_int calls.
Does the third one do the charm? I haven't compiled the other arch's,
but i386 is running fine.
--
Martin Pelikan
Index: arch/hp300/hp300/trap.c
===================================================================
RCS file: /cvs/src/sys/arch/hp300/hp300/trap.c,v
retrieving revision 1.62
diff -u -p -r1.62 trap.c
--- arch/hp300/hp300/trap.c 31 Dec 2012 06:46:13 -0000 1.62
+++ arch/hp300/hp300/trap.c 20 Jun 2013 12:51:46 -0000
@@ -321,7 +321,7 @@ dopanic:
i = sigmask(SIGILL);
p->p_sigacts->ps_sigignore &= ~i;
p->p_sigacts->ps_sigcatch &= ~i;
- p->p_sigmask &= ~i;
+ atomic_clearbits_int(&p->p_sigmask, i);
i = SIGILL;
ucode = frame.f_format; /* XXX was ILL_RESAD_FAULT */
typ = ILL_COPROC;
Index: arch/mvme68k/mvme68k/trap.c
===================================================================
RCS file: /cvs/src/sys/arch/mvme68k/mvme68k/trap.c,v
retrieving revision 1.77
diff -u -p -r1.77 trap.c
--- arch/mvme68k/mvme68k/trap.c 31 Dec 2012 06:46:13 -0000 1.77
+++ arch/mvme68k/mvme68k/trap.c 20 Jun 2013 12:51:47 -0000
@@ -260,7 +260,7 @@ copyfault:
i = sigmask(SIGILL);
p->p_sigacts->ps_sigignore &= ~i;
p->p_sigacts->ps_sigcatch &= ~i;
- p->p_sigmask &= ~i;
+ atomic_clearbits_int(&p->p_sigmask, i);
i = SIGILL;
ucode = frame.f_format; /* XXX was ILL_RESAD_FAULT */
typ = ILL_COPROC;
Index: compat/linux/linux_signal.c
===================================================================
RCS file: /cvs/src/sys/compat/linux/linux_signal.c,v
retrieving revision 1.15
diff -u -p -r1.15 linux_signal.c
--- compat/linux/linux_signal.c 19 Jun 2012 11:35:29 -0000 1.15
+++ compat/linux/linux_signal.c 20 Jun 2013 12:51:49 -0000
@@ -584,7 +584,6 @@ linux_sys_sigprocmask(p, v, retval)
linux_old_sigset_t ss;
sigset_t bs;
int error = 0;
- int s;
*retval = 0;
@@ -604,19 +603,18 @@ linux_sys_sigprocmask(p, v, retval)
linux_old_to_bsd_sigset(&ss, &bs);
- s = splhigh();
-
+ bs &= ~sigcantmask;
switch (SCARG(uap, how)) {
case LINUX_SIG_BLOCK:
- p->p_sigmask |= bs & ~sigcantmask;
+ atomic_setbits_int(&p->p_sigmask, bs);
break;
case LINUX_SIG_UNBLOCK:
- p->p_sigmask &= ~bs;
+ atomic_clearbits_int(&p->p_sigmask, bs);
break;
case LINUX_SIG_SETMASK:
- p->p_sigmask = bs & ~sigcantmask;
+ p->p_sigmask = bs;
break;
default:
@@ -624,8 +622,6 @@ linux_sys_sigprocmask(p, v, retval)
break;
}
- splx(s);
-
return (error);
}
@@ -644,7 +640,6 @@ linux_sys_rt_sigprocmask(p, v, retval)
linux_sigset_t ls;
sigset_t bs;
int error = 0;
- int s;
if (SCARG(uap, sigsetsize) != sizeof(linux_sigset_t))
return (EINVAL);
@@ -667,19 +662,18 @@ linux_sys_rt_sigprocmask(p, v, retval)
linux_to_bsd_sigset(&ls, &bs);
- s = splhigh();
-
+ bs &= ~sigcantmask;
switch (SCARG(uap, how)) {
case LINUX_SIG_BLOCK:
- p->p_sigmask |= bs & ~sigcantmask;
+ atomic_setbits_int(&p->p_sigmask, bs);
break;
case LINUX_SIG_UNBLOCK:
- p->p_sigmask &= ~bs;
+ atomic_clearbits_int(&p->p_sigmask, bs);
break;
case LINUX_SIG_SETMASK:
- p->p_sigmask = bs & ~sigcantmask;
+ p->p_sigmask = bs;
break;
default:
@@ -687,8 +681,6 @@ linux_sys_rt_sigprocmask(p, v, retval)
break;
}
- splx(s);
-
return (error);
}
@@ -727,16 +719,13 @@ linux_sys_sigsetmask(p, v, retval)
} */ *uap = v;
linux_old_sigset_t mask;
sigset_t bsdsig;
- int s;
bsd_to_linux_old_sigset(&p->p_sigmask, (linux_old_sigset_t *)retval);
mask = SCARG(uap, mask);
bsd_to_linux_old_sigset(&bsdsig, &mask);
- s = splhigh();
p->p_sigmask = bsdsig & ~sigcantmask;
- splx(s);
return (0);
}
Index: kern/init_sysent.c
===================================================================
RCS file: /cvs/src/sys/kern/init_sysent.c,v
retrieving revision 1.145
diff -u -p -r1.145 init_sysent.c
--- kern/init_sysent.c 9 Jun 2013 13:10:27 -0000 1.145
+++ kern/init_sysent.c 20 Jun 2013 12:51:49 -0000
@@ -136,7 +136,7 @@ struct sysent sysent[] = {
sys_sigaction }, /* 46 = sigaction */
{ 0, 0, 0,
sys_getgid }, /* 47 = getgid */
- { 2, s(struct sys_sigprocmask_args), 0,
+ { 2, s(struct sys_sigprocmask_args), SY_NOLOCK | 0,
sys_sigprocmask }, /* 48 = sigprocmask */
{ 2, s(struct sys_getlogin_args), 0,
sys_getlogin }, /* 49 = getlogin */
Index: kern/kern_sig.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_sig.c,v
retrieving revision 1.152
diff -u -p -r1.152 kern_sig.c
--- kern/kern_sig.c 1 Jun 2013 04:05:26 -0000 1.152
+++ kern/kern_sig.c 20 Jun 2013 12:51:49 -0000
@@ -429,28 +429,25 @@ sys_sigprocmask(struct proc *p, void *v,
syscallarg(sigset_t) mask;
} */ *uap = v;
int error = 0;
- int s;
sigset_t mask;
*retval = p->p_sigmask;
- mask = SCARG(uap, mask);
- s = splhigh();
+ mask = SCARG(uap, mask) &~ sigcantmask;
switch (SCARG(uap, how)) {
case SIG_BLOCK:
- p->p_sigmask |= mask &~ sigcantmask;
+ atomic_setbits_int(&p->p_sigmask, mask);
break;
case SIG_UNBLOCK:
- p->p_sigmask &= ~mask;
+ atomic_clearbits_int(&p->p_sigmask, mask);
break;
case SIG_SETMASK:
- p->p_sigmask = mask &~ sigcantmask;
+ p->p_sigmask = mask;
break;
default:
error = EINVAL;
break;
}
- splx(s);
return (error);
}
@@ -739,7 +736,7 @@ trapsignal(struct proc *p, int signum, u
p->p_ru.ru_nsignals++;
(*p->p_emul->e_sendsig)(ps->ps_sigact[signum], signum,
p->p_sigmask, trapno, code, sigval);
- p->p_sigmask |= ps->ps_catchmask[signum];
+ atomic_setbits_int(&p->p_sigmask, ps->ps_catchmask[signum]);
if ((ps->ps_sigreset & mask) != 0) {
ps->ps_sigcatch &= ~mask;
if (signum != SIGCONT && sigprop[signum] & SA_IGNORE)
@@ -1334,7 +1331,7 @@ postsig(int signum)
} else {
returnmask = p->p_sigmask;
}
- p->p_sigmask |= ps->ps_catchmask[signum];
+ atomic_setbits_int(&p->p_sigmask, ps->ps_catchmask[signum]);
if ((ps->ps_sigreset & mask) != 0) {
ps->ps_sigcatch &= ~mask;
if (signum != SIGCONT && sigprop[signum] & SA_IGNORE)
Index: kern/syscalls.master
===================================================================
RCS file: /cvs/src/sys/kern/syscalls.master,v
retrieving revision 1.133
diff -u -p -r1.133 syscalls.master
--- kern/syscalls.master 9 Jun 2013 13:10:19 -0000 1.133
+++ kern/syscalls.master 20 Jun 2013 12:51:49 -0000
@@ -123,7 +123,7 @@
const struct sigaction *nsa, \
struct sigaction *osa); }
47 STD { gid_t sys_getgid(void); }
-48 STD { int sys_sigprocmask(int how, sigset_t mask); }
+48 STD NOLOCK { int sys_sigprocmask(int how, sigset_t mask); }
49 STD { int sys_getlogin(char *namebuf, u_int namelen); }
50 STD { int sys_setlogin(const char *namebuf); }
#ifdef ACCOUNTING
