The write_sigio thread is not really a traditional thread. Set
the parent-death signal for it to ensure that it will be killed
if the UML kernel dies unexpectedly without proper cleanup.

Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
---
 arch/um/os-Linux/sigio.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/um/os-Linux/sigio.c b/arch/um/os-Linux/sigio.c
index 9e71794839e8..9aac8def4d63 100644
--- a/arch/um/os-Linux/sigio.c
+++ b/arch/um/os-Linux/sigio.c
@@ -55,6 +55,7 @@ static int write_sigio_thread(void *unused)
 	int i, n, respond_fd;
 	char c;
 
+	os_set_pdeathsig();
 	os_fix_helper_signals();
 	fds = &current_poll;
 	while (1) {
-- 
2.34.1