My understanding of sigsuspend(2) is that it only returns if a signal
is delivered to the calling thread. However, in sys_sigsuspend() we
pass &p->p_p->ps_sigacts as the wakeup channel to tsleep_nsec(9).
Are we actually waiting for a wakeup on that channel? Or can we sleep
on &nowake here? Patch attached. Note that we don't need to loop
here anymore: we can't receieve wakeup so tsleep_nsec(9) will never
return zero.
I can't find any wakeups in the kernel sent to any ps_sigacts, but
maybe I missed something.
If not, ok?
Index: kern_sig.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_sig.c,v
retrieving revision 1.287
diff -u -p -r1.287 kern_sig.c
--- kern_sig.c 24 Oct 2021 00:02:25 -0000 1.287
+++ kern_sig.c 11 Nov 2021 19:24:49 -0000
@@ -509,7 +509,7 @@ dosigsuspend(struct proc *p, sigset_t ne
}
/*
- * Suspend process until signal, providing mask to be set
+ * Suspend thread until signal, providing mask to be set
* in the meantime. Note nonstandard calling convention:
* libc stub passes mask, not pointer, to save a copyin.
*/
@@ -519,12 +519,9 @@ sys_sigsuspend(struct proc *p, void *v,
struct sys_sigsuspend_args /* {
syscallarg(int) mask;
} */ *uap = v;
- struct process *pr = p->p_p;
- struct sigacts *ps = pr->ps_sigacts;
dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask);
- while (tsleep_nsec(ps, PPAUSE|PCATCH, "sigsusp", INFSLP) == 0)
- /* void */;
+ tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigsusp", INFSLP);
/* always return EINTR rather than ERESTART... */
return (EINTR);
}
