If I understand correctly death_cookie was needed before
"[PATCH] Embed struct utrace in task_struct - V2".
tracehook_report_death() could race with utrace_release_task() which
cleared ->utrace, that is why tracehook_notify_death() had to read
task_utrace_struct() in advance and then pass this argument to
utrace_report_death().
Looks like this is not needed any longer, kill this awful cookie.
Signed-off-by: Oleg Nesterov <o...@redhat.com>
--- xxx/include/linux/utrace.h~KILL_COOKIE 2009-03-03 18:11:47.000000000
+0100
+++ xxx/include/linux/utrace.h 2009-03-03 20:43:43.000000000 +0100
@@ -100,7 +100,7 @@ void utrace_finish_vfork(struct task_str
__attribute__((weak));
void utrace_report_exit(long *exit_code)
__attribute__((weak));
-void utrace_report_death(struct task_struct *, struct utrace *, bool, int)
+void utrace_report_death(struct task_struct *, bool, int)
__attribute__((weak));
void utrace_report_jctl(int notify, int type)
__attribute__((weak));
--- xxx/include/linux/tracehook.h~KILL_COOKIE 2009-03-03 18:11:47.000000000
+0100
+++ xxx/include/linux/tracehook.h 2009-03-03 20:40:57.000000000 +0100
@@ -534,7 +534,6 @@ static inline int tracehook_notify_jctl(
/**
* tracehook_notify_death - task is dead, ready to notify parent
* @task: @current task now exiting
- * @death_cookie: value to pass to tracehook_report_death()
* @group_dead: nonzero if this was the last thread in the
group to die
*
* A return value >= 0 means call do_notify_parent() with that signal
@@ -546,10 +545,8 @@ static inline int tracehook_notify_jctl(
* Called with write_lock_irq(&tasklist_lock) held.
*/
static inline int tracehook_notify_death(struct task_struct *task,
- void **death_cookie, int group_dead)
+ int group_dead)
{
- *death_cookie = task_utrace_struct(task);
-
if (task->exit_signal == -1)
return task->ptrace ? SIGCHLD : DEATH_REAP;
@@ -568,14 +565,12 @@ static inline int tracehook_notify_death
* tracehook_report_death - task is dead and ready to be reaped
* @task: @current task now exiting
* @signal: return value from tracheook_notify_death()
- * @death_cookie: value passed back from tracehook_notify_death()
* @group_dead: nonzero if this was the last thread in the
group to die
*
* Thread has just become a zombie or is about to self-reap. If positive,
* @signal is the signal number just sent to the parent (usually %SIGCHLD).
* If @signal is %DEATH_REAP, this thread will self-reap. If @signal is
* %DEATH_DELAYED_GROUP_LEADER, this is a delayed_group_leader() zombie.
- * The @death_cookie was passed back by tracehook_notify_death().
*
* If normal reaping is not inhibited, @task->exit_state might be changing
* in parallel.
@@ -583,13 +578,12 @@ static inline int tracehook_notify_death
* Called without locks.
*/
static inline void tracehook_report_death(struct task_struct *task,
- int signal, void *death_cookie,
- int group_dead)
+ int signal, int group_dead)
{
smp_mb();
if (task_utrace_flags(task) & (UTRACE_EVENT(DEATH) |
UTRACE_EVENT(QUIESCE)))
- utrace_report_death(task, death_cookie, group_dead, signal);
+ utrace_report_death(task, group_dead, signal);
}
#ifdef TIF_NOTIFY_RESUME
--- xxx/kernel/exit.c~KILL_COOKIE 2009-03-03 18:11:47.000000000 +0100
+++ xxx/kernel/exit.c 2009-03-03 20:42:20.000000000 +0100
@@ -917,7 +917,6 @@ static void forget_original_parent(struc
static void exit_notify(struct task_struct *tsk, int group_dead)
{
int signal;
- void *cookie;
/*
* This does two things:
@@ -954,7 +953,7 @@ static void exit_notify(struct task_stru
!capable(CAP_KILL))
tsk->exit_signal = SIGCHLD;
- signal = tracehook_notify_death(tsk, &cookie, group_dead);
+ signal = tracehook_notify_death(tsk, group_dead);
if (signal >= 0)
signal = do_notify_parent(tsk, signal);
@@ -968,7 +967,7 @@ static void exit_notify(struct task_stru
write_unlock_irq(&tasklist_lock);
- tracehook_report_death(tsk, signal, cookie, group_dead);
+ tracehook_report_death(tsk, signal, group_dead);
/* If the process is dead, release it - nobody will wait for it */
if (signal == DEATH_REAP)
--- xxx/kernel/utrace.c~KILL_COOKIE 2009-03-03 18:11:47.000000000 +0100
+++ xxx/kernel/utrace.c 2009-03-03 20:46:09.000000000 +0100
@@ -1675,9 +1675,9 @@ void utrace_report_exit(long *exit_code)
* For this reason, utrace_release_task checks for the event bits that get
* us here, and delays its cleanup for us to do.
*/
-void utrace_report_death(struct task_struct *task, struct utrace *utrace,
- bool group_dead, int signal)
+void utrace_report_death(struct task_struct *task, bool group_dead, int signal)
{
+ struct utrace *utrace = task_utrace_struct(task);
INIT_REPORT(report);
BUG_ON(!task->exit_state);
