Copy siginfo_t to step before calling a user-space signal handler

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5769 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 14 insertions, 1 deletions

diff --git a/nuttx/sched/sig_deliver.c b/nuttx/sched/sig_deliver.c
index bb6ca71a4..9b1e8cebe 100644
--- a/nuttx/sched/sig_deliver.c
+++ b/nuttx/sched/sig_deliver.c
@@ -136,12 +136,25 @@ void sig_deliver(FAR struct tcb_s *stcb)
 #ifdef CONFIG_NUTTX_KERNEL
       if ((stcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_KERNEL)
         {
+          /* The sigq_t pointed to by sigq resides in kernel space.  So we
+           * cannot pass a reference to sigq->info to the user space.
+           * Instead, we will copy the siginfo_t structure onto that stack.
+           * We are currently executing on the stack of the user thread
+           * (albeit temporarily in kernel mode), so the copy of the
+           * siginfo_t structure will be accessible by the user thread.
+           */
+
+          siginfo_t info;
+          memcpy(&info, sigq->info, sizeof(siginfo_t));
+
           up_signal_handler(sigq->action.sighandler, sigq->info.si_signo,
-                            &sigq->info, NULL);
+                            &info, NULL);
         }
       else
 #endif
         {
+          /* The kernel thread signal handler is much simpler. */
+
           (*sigq->action.sighandler)(sigq->info.si_signo, &sigq->info,
                                      NULL);
         }