um: Cleanup SIGTERM handling

Richard reported that some UML processes survive if the UML
main process receives a SIGTERM.
This issue was caused by a wrongly placed signal(SIGTERM, SIG_DFL)
in init_new_thread_signals().
It disabled the UML exit handler accidently for some processes.
The correct solution is to disable the fatal handler for all
UML helper threads/processes.
Such that last_ditch_exit() does not get called multiple times
and all processes can exit due to SIGTERM.

Reported-and-tested-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

1 files changed, 2 insertions, 3 deletions

diff --git a/arch/um/os-Linux/aio.c b/arch/um/os-Linux/aio.c
index 3a6bc2af0961..014eb35fd13b 100644
--- a/arch/um/os-Linux/aio.c
+++ b/arch/um/os-Linux/aio.c
@@ -104,8 +104,7 @@ static int aio_thread(void *arg)
         struct io_event event;
         int err, n, reply_fd;
 
-        signal(SIGWINCH, SIG_IGN);
-
+        os_fix_helper_signals();
         while (1) {
                 n = io_getevents(ctx, 1, 1, &event, NULL);
                 if (n < 0) {
@@ -173,7 +172,7 @@ static int not_aio_thread(void *arg)
         struct aio_thread_reply reply;
         int err;
 
-        signal(SIGWINCH, SIG_IGN);
+        os_fix_helper_signals();
         while (1) {
                 err = read(aio_req_fd_r, &req, sizeof(req));
                 if (err != sizeof(req)) {