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>
diff --git a/arch/um/os-Linux/aio.c b/arch/um/os-Linux/aio.c
index 3a6bc2a..014eb35 100644
--- a/arch/um/os-Linux/aio.c
+++ b/arch/um/os-Linux/aio.c
@@ -104,8 +104,7 @@
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 @@
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)) {
diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c
index 67b9c8f..33496fe 100644
--- a/arch/um/os-Linux/process.c
+++ b/arch/um/os-Linux/process.c
@@ -294,5 +294,4 @@
signal(SIGHUP, SIG_IGN);
set_handler(SIGIO);
signal(SIGWINCH, SIG_IGN);
- signal(SIGTERM, SIG_DFL);
}
diff --git a/arch/um/os-Linux/sigio.c b/arch/um/os-Linux/sigio.c
index 8b61cc0..46e762f 100644
--- a/arch/um/os-Linux/sigio.c
+++ b/arch/um/os-Linux/sigio.c
@@ -55,7 +55,7 @@
int i, n, respond_fd;
char c;
- signal(SIGWINCH, SIG_IGN);
+ os_fix_helper_signals();
fds = ¤t_poll;
while (1) {
n = poll(fds->poll, fds->used, -1);
diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c
index 492ef5e..faee55e 100644
--- a/arch/um/os-Linux/util.c
+++ b/arch/um/os-Linux/util.c
@@ -94,6 +94,16 @@
exit(127);
}
+/*
+ * UML helper threads must not handle SIGWINCH/INT/TERM
+ */
+void os_fix_helper_signals(void)
+{
+ signal(SIGWINCH, SIG_IGN);
+ signal(SIGINT, SIG_DFL);
+ signal(SIGTERM, SIG_DFL);
+}
+
void os_dump_core(void)
{
int pid;