pm - sys_sigsend can fail legitimately

  . specifically, if a signal handler can't be invoked due
    to process memory, EFAULT is returned from the kernel.
    don't panic() then.

diff --git a/servers/pm/signal.c b/servers/pm/signal.c
index fce84ca9c990e07479f4352412695ad68f5fa06a..263d49fadf94758c296fddf80e1c564394a2865e 100644 (file)
--- a/servers/pm/signal.c
+++ b/servers/pm/signal.c
@@ -449,6 +449,8 @@ int ksig;                   /* non-zero means signal comes from kernel  */
                return;
 
        /* We were unable to spawn a signal handler. Kill the process. */
+       printf("PM: %d can't catch signal %d - killing\n",
+               rmp->mp_pid, signo);
   }
   else if (!badignore && sigismember(&ign_sset, signo)) {
        /* Signal defaults to being ignored. */
@@ -732,8 +734,16 @@ int signo;                 /* signal to send to process (1 to _NSIG-1) */
 
   /* Ask the kernel to deliver the signal */
   r = sys_sigsend(rmp->mp_endpoint, &sigmsg);
-  if (r != OK)
+ /* sys_sigsend can fail legitimately with EFAULT if
+  * the process memory can't accomodate the signal handler.
+  */
+  if(r == EFAULT) {
+       return(FALSE);
+  }
+  /* Other errors are unexpected pm/kernel discrepancies. */
+  if (r != OK) {
        panic("sys_sigsend failed: %d", r);
+  }
 
   /* Was the process suspended in PM? Then interrupt the blocking call. */
   if (rmp->mp_flags & (PAUSED | WAITING | SIGSUSPENDED)) {