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.
Cc: rjo...@redhat.com
Reported-by: Richard W.M. Jones <rjo...@redhat.com>
Signed-off-by: Richard Weinberger <rich...@nod.at>
---
arch/um/drivers/ubd.h | 1 -
arch/um/drivers/ubd_kern.c | 3 ++-
arch/um/drivers/ubd_user.c | 5 -----
arch/um/include/shared/os.h | 1 +
arch/um/os-Linux/aio.c | 5 ++---
arch/um/os-Linux/process.c | 1 -
arch/um/os-Linux/sigio.c | 2 +-
arch/um/os-Linux/util.c | 10 ++++++++++
8 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/arch/um/drivers/ubd.h b/arch/um/drivers/ubd.h
index 3845051..3b48cd2 100644
--- a/arch/um/drivers/ubd.h
+++ b/arch/um/drivers/ubd.h
@@ -7,7 +7,6 @@
#ifndef __UM_UBD_USER_H
#define __UM_UBD_USER_H
-extern void ignore_sigwinch_sig(void);
extern int start_io_thread(unsigned long sp, int *fds_out);
extern int io_thread(void *arg);
extern int kernel_fd;
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 1812bc8..3716e69 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -1476,7 +1476,8 @@ int io_thread(void *arg)
struct io_thread_req *req;
int n;
- ignore_sigwinch_sig();
+ os_fix_helper_signals();
+
while(1){
n = os_read_file(kernel_fd, &req,
sizeof(struct io_thread_req *));
diff --git a/arch/um/drivers/ubd_user.c b/arch/um/drivers/ubd_user.c
index a703e45..e376f9b 100644
--- a/arch/um/drivers/ubd_user.c
+++ b/arch/um/drivers/ubd_user.c
@@ -21,11 +21,6 @@
#include "ubd.h"
#include <os.h>
-void ignore_sigwinch_sig(void)
-{
- signal(SIGWINCH, SIG_IGN);
-}
-
int start_io_thread(unsigned long sp, int *fd_out)
{
int pid, fds[2], err;
diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h
index 04859b7..24d8077 100644
--- a/arch/um/include/shared/os.h
+++ b/arch/um/include/shared/os.h
@@ -234,6 +234,7 @@ extern void setup_machinename(char *machine_out);
extern void setup_hostinfo(char *buf, int len);
extern void os_dump_core(void) __attribute__ ((noreturn));
extern void um_early_printk(const char *s, unsigned int n);
+extern void os_fix_helper_signals(void);
/* time.c */
extern void idle_sleep(unsigned long long nsecs);
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 @@ 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)) {
diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c
index b8f34c9..7cd61ea 100644
--- a/arch/um/os-Linux/process.c
+++ b/arch/um/os-Linux/process.c
@@ -242,5 +242,4 @@ void init_new_thread_signals(void)
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 @@ static int write_sigio_thread(void *unused)
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 @@ static inline void __attribute__ ((noreturn)) uml_abort(void)
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;
--
1.8.3.1
------------------------------------------------------------------------------
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