The initial task scan runs before the first patch registers the task exit
tracepoint. A task can begin exiting after it was selected by the scan but
before the exit handler is attached. sched_process_exit runs before
exit_notify() removes the task from the task list, so the scan could then
store a pointer to the exiting task's deadline entity after its cleanup
event had already been missed.
Initialize the shard state and attach the new-task, exit, and syscall
tracepoints before the initial scan. Make the scan use the same
PF_EXITING-aware creation helper as dynamic policy changes. On failure,
detach those tracepoints before destroying the monitor storage.
Fixes: b133207deb72 ("rv: Add nomiss deadline monitor")
Signed-off-by: Li Qiang <[email protected]>
---
kernel/trace/rv/monitors/deadline/deadline.h | 27 ++++++++++-------
kernel/trace/rv/monitors/nomiss/nomiss.c | 18 +++++++----
2 files changed, 30 insertions(+), 15 deletions(-)
diff --git a/kernel/trace/rv/monitors/deadline/deadline.h
b/kernel/trace/rv/monitors/deadline/deadline.h
index b92480e79807..4626d6e2b218 100644
--- a/kernel/trace/rv/monitors/deadline/deadline.h
+++ b/kernel/trace/rv/monitors/deadline/deadline.h
@@ -181,6 +181,8 @@ static void deadline_storage_init(void)
}
}
+static int deadline_create_task_storage(struct task_struct *task);
+
/*
* Initialise monitors for all tasks and pre-allocate the storage for servers.
* This is necessary since we don't have access to the servers here and
@@ -190,9 +192,7 @@ static void deadline_storage_init(void)
static inline int init_storage(bool skip_tasks)
{
struct task_struct *g, *p;
- int cpu;
-
- deadline_storage_init();
+ int cpu, ret;
for_each_possible_cpu(cpu) {
if (!da_create_empty_storage(fair_server_id(cpu)))
@@ -208,25 +208,25 @@ static inline int init_storage(bool skip_tasks)
read_lock(&tasklist_lock);
for_each_process_thread(g, p) {
if (p->policy == SCHED_DEADLINE) {
- if (!da_create_storage(EXPAND_ID_TASK(p), NULL)) {
+ ret = deadline_create_task_storage(p);
+ if (ret && ret != -ESRCH) {
read_unlock(&tasklist_lock);
- goto fail;
+ return ret;
}
- atomic_inc(&deadline_storage_shard(p->pid)->users);
}
}
read_unlock(&tasklist_lock);
return 0;
fail:
- da_monitor_destroy();
return -ENOMEM;
}
-static void deadline_create_task_storage(struct task_struct *task)
+static int deadline_create_task_storage(struct task_struct *task)
{
struct deadline_storage_shard *shard =
deadline_storage_shard(task->pid);
bool created = false;
+ int ret = -ESRCH;
/*
* The temporary reference makes an in-flight creator visible to exit.
@@ -239,14 +239,21 @@ static void deadline_create_task_storage(struct
task_struct *task)
raw_spin_lock(&shard->lock);
if (!(READ_ONCE(task->flags) & PF_EXITING)) {
guard(rcu)();
- if (!da_get_monitor(EXPAND_ID_TASK(task)) &&
- da_create_storage(EXPAND_ID_TASK(task), NULL))
+ if (da_get_monitor(EXPAND_ID_TASK(task))) {
+ ret = 0;
+ } else if (da_create_storage(EXPAND_ID_TASK(task), NULL)) {
created = true;
+ ret = 0;
+ } else {
+ ret = -ENOMEM;
+ }
}
raw_spin_unlock(&shard->lock);
if (!created)
atomic_dec(&shard->users);
+
+ return ret;
}
static void deadline_destroy_task_storage(struct task_struct *task)
diff --git a/kernel/trace/rv/monitors/nomiss/nomiss.c
b/kernel/trace/rv/monitors/nomiss/nomiss.c
index 2e5ee681505b..843262779a41 100644
--- a/kernel/trace/rv/monitors/nomiss/nomiss.c
+++ b/kernel/trace/rv/monitors/nomiss/nomiss.c
@@ -231,18 +231,26 @@ static int enable_nomiss(void)
if (retval)
return retval;
+ deadline_storage_init();
+ rv_attach_trace_probe("nomiss", task_newtask, handle_newtask);
+ rv_attach_trace_probe("nomiss", sched_process_exit, handle_exit);
+ if (!should_skip_syscall_handle())
+ rv_attach_trace_probe("nomiss", sys_enter, handle_sys_enter);
+
retval = init_storage(false);
- if (retval)
+ if (retval) {
+ rv_detach_trace_probe("nomiss", task_newtask, handle_newtask);
+ rv_detach_trace_probe("nomiss", sched_process_exit,
handle_exit);
+ if (!should_skip_syscall_handle())
+ rv_detach_trace_probe("nomiss", sys_enter,
handle_sys_enter);
+ ha_monitor_destroy();
return retval;
+ }
rv_attach_trace_probe("nomiss", sched_dl_replenish_tp,
handle_dl_replenish);
rv_attach_trace_probe("nomiss", sched_dl_throttle_tp,
handle_dl_throttle);
rv_attach_trace_probe("nomiss", sched_dl_server_stop_tp,
handle_dl_server_stop);
rv_attach_trace_probe("nomiss", sched_switch, handle_sched_switch);
rv_attach_trace_probe("nomiss", sched_wakeup, handle_sched_wakeup);
- if (!should_skip_syscall_handle())
- rv_attach_trace_probe("nomiss", sys_enter, handle_sys_enter);
- rv_attach_trace_probe("nomiss", task_newtask, handle_newtask);
- rv_attach_trace_probe("nomiss", sched_process_exit, handle_exit);
return 0;
}
--
2.50.1
