Move the single_thread_check() to the start of userret().

This way threads stopped by SINGLE_SUSPEND will check for pending
signals right after being released instead of returning to userland
first. The same order of check is already used in sleep_signal_check().

OK mpi@

diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index fba5f72..098e199 100644 (file)
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kern_sig.c,v 1.310 2023/07/14 07:07:08 claudio Exp $  */
+/*     $OpenBSD: kern_sig.c,v 1.311 2023/08/11 07:54:18 claudio Exp $  */
 /*     $NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $   */
 
 /*
@@ -1970,6 +1970,9 @@ userret(struct proc *p)
        struct sigctx ctx;
        int signum;
 
+       if (p->p_flag & P_SUSPSINGLE)
+               single_thread_check(p, 0);
+
        /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */
        if (p->p_flag & P_PROFPEND) {
                atomic_clearbits_int(&p->p_flag, P_PROFPEND);
@@ -2003,9 +2006,6 @@ userret(struct proc *p)
                        postsig(p, signum, &ctx);
        }
 
-       if (p->p_flag & P_SUSPSINGLE)
-               single_thread_check(p, 0);
-
        WITNESS_WARN(WARN_PANIC, NULL, "userret: returning");
 
        p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri;