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authorRichard Weinberger <richard@nod.at>2013-08-18 13:30:08 +0200
committerRichard Weinberger <richard@nod.at>2013-09-07 10:56:58 +0200
commit91d44ff860a9e9c0db81a89cbc24fa31fbd8e6d3 (patch)
treebb14601ab3afbcec3cb8d7d0f207d09cfc792268 /arch/um
parentbc1d72e73be63a7c4a07eb10cf51e91f20bf6076 (diff)
downloadtalos-obmc-linux-91d44ff860a9e9c0db81a89cbc24fa31fbd8e6d3.tar.gz
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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>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/drivers/ubd.h1
-rw-r--r--arch/um/drivers/ubd_kern.c3
-rw-r--r--arch/um/drivers/ubd_user.c5
-rw-r--r--arch/um/include/shared/os.h1
-rw-r--r--arch/um/os-Linux/aio.c5
-rw-r--r--arch/um/os-Linux/process.c1
-rw-r--r--arch/um/os-Linux/sigio.c2
-rw-r--r--arch/um/os-Linux/util.c10
8 files changed, 16 insertions, 12 deletions
diff --git a/arch/um/drivers/ubd.h b/arch/um/drivers/ubd.h
index 3845051f1b10..3b48cd2081ee 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 1812bc81715b..3716e6952554 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 a703e45d8aac..e376f9b9c68d 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 e98303925cc5..021104d98cb3 100644
--- a/arch/um/include/shared/os.h
+++ b/arch/um/include/shared/os.h
@@ -235,6 +235,7 @@ 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 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)) {
diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c
index 67b9c8f5a89e..33496fe2bb52 100644
--- a/arch/um/os-Linux/process.c
+++ b/arch/um/os-Linux/process.c
@@ -294,5 +294,4 @@ 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 8b61cc0e82c8..46e762f926eb 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 = &current_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 492ef5e6e166..faee55ef6d2f 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;
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