From: Andrew Vagin <avagin at virtuozzo.com>
We can do this, but we need to be sure that all structures
are consistant in any moment and we need to block alarm when
they are inconsistant.
I don't think that we really want to do this now. I suggest to
interupt a current syscall if an alarm signal is triggered.
https://jira.sw.ru/browse/PSBM-44371
v2: print an error message before exiting
Cc: Andrey Ryabinin <aryabinin at virtuozzo.com>
Signed-off-by: Andrew Vagin <avagin at virtuozzo.com>
---
criu/cr-dump.c | 45 +++++++++++++++++++++++----------------------
criu/include/seize.h | 1 +
criu/seize.c | 22 +++++++++++++++-------
3 files changed, 39 insertions(+), 29 deletions(-)
diff --git a/criu/cr-dump.c b/criu/cr-dump.c
index 8f2587b..acb6cbe 100644
--- a/criu/cr-dump.c
+++ b/criu/cr-dump.c
@@ -1366,13 +1366,30 @@ err_cure_imgset:
goto err;
}
-typedef void (*sa_handler_t)(int);
+static int alarm_attempts = 0;
-static int setup_alarm_handler(sa_handler_t handler)
+bool alarm_timeouted() {
+ return alarm_attempts > 0;
+}
+
+static void alarm_handler(int signo)
+{
+
+ pr_err("Timeout reached. Try to interrupt: %d\n", alarm_attempts);
+ if (alarm_attempts++ < 5) {
+ alarm(1);
+ /* A curren syscall will be exited with EINTR */
+ return;
+ }
+ pr_err("FATAL: Unable to interrupt the current operation\n");
+ BUG();
+}
+
+static int setup_alarm_handler()
{
struct sigaction sa = {
- .sa_handler = handler,
- .sa_flags = 0,
+ .sa_handler = alarm_handler,
+ .sa_flags = 0, /* Don't restart syscalls */
};
sigemptyset(&sa.sa_mask);
@@ -1437,15 +1454,6 @@ static int cr_pre_dump_finish(struct list_head *ctls, int ret)
return ret;
}
-void pre_dump_alarm_handler(int signum)
-{
- LIST_HEAD(empty_list);
-
- pr_err("Timeout reached\n");
- cr_pre_dump_finish(&empty_list, -1);
- exit(-1);
-}
-
int cr_pre_dump_tasks(pid_t pid)
{
struct pstree_item *item;
@@ -1483,7 +1491,7 @@ int cr_pre_dump_tasks(pid_t pid)
if (connect_to_page_server())
goto err;
- if (setup_alarm_handler(pre_dump_alarm_handler))
+ if (setup_alarm_handler())
goto err;
if (collect_pstree(pid))
@@ -1585,13 +1593,6 @@ static int cr_dump_finish(int ret)
return post_dump_ret ? : (ret != 0);
}
-void dump_alarm_handler(int signum)
-{
- pr_err("Timeout reached\n");
- cr_dump_finish(-1);
- exit(-1);
-}
-
int cr_dump_tasks(pid_t pid)
{
InventoryEntry he = INVENTORY_ENTRY__INIT;
@@ -1640,7 +1641,7 @@ int cr_dump_tasks(pid_t pid)
if (connect_to_page_server())
goto err;
- if (setup_alarm_handler(dump_alarm_handler))
+ if (setup_alarm_handler())
goto err;
/*
diff --git a/criu/include/seize.h b/criu/include/seize.h
index 315fab2..9cfebb1 100644
--- a/criu/include/seize.h
+++ b/criu/include/seize.h
@@ -4,5 +4,6 @@
extern int collect_pstree(pid_t pid);
extern void pstree_switch_state(struct pstree_item *root_item, int st);
extern const char *get_real_freezer_state(void);
+extern bool alarm_timeouted(void);
#endif
diff --git a/criu/seize.c b/criu/seize.c
index b922723..3fd3d62 100644
--- a/criu/seize.c
+++ b/criu/seize.c
@@ -297,6 +297,9 @@ static int freeze_processes(void)
continue;
}
+ if (alarm_timeouted())
+ goto err;
+
timeout = 100000000 * (i + 1); /* 100 msec */
req.tv_nsec = timeout % 1000000000;
req.tv_sec = timeout / 1000000000;
@@ -357,6 +360,11 @@ static int collect_children(struct pstree_item *item)
nr_inprogress++;
+ if (alarm_timeouted()) {
+ ret = -1;
+ goto free;
+ }
+
pr_info("Seized task %d, state %d\n", pid, ret);
c = alloc_pstree_item();
@@ -642,6 +650,13 @@ int collect_pstree(pid_t pid)
timing_start(TIME_FREEZING);
+ /*
+ * wait4() may hang for some reason. Enable timer and fire SIGALRM
+ * if timeout reached. SIGALRM handler will do the necessary
+ * cleanups and terminate current process.
+ */
+ alarm(opts.timeout);
+
if (opts.freeze_cgroup && freeze_processes())
goto err;
@@ -656,13 +671,6 @@ int collect_pstree(pid_t pid)
goto err;
}
- /*
- * wait4() may hang for some reason. Enable timer and fire SIGALRM
- * if timeout reached. SIGALRM handler will do the necessary
- * cleanups and terminate current process.
- */
- alarm(opts.timeout);
-
ret = seize_wait_task(pid, -1, &dmpi(root_item)->pi_creds);
if (ret < 0)
goto err;
--
2.5.0