On 04/15, Andrey Wagin wrote:
>
> It looks good for me. I have tested it a bit and don't find any problem.
> Oleg, thank you.
>
> Acked-by: Andrew Vagin <[email protected]>
Thanks Andrey and Eric.
> > --- x/kernel/exit.c
> > +++ x/kernel/exit.c
> > @@ -649,7 +649,6 @@ static void exit_notify(struct task_stru
> > * jobs, send them a SIGHUP and then a SIGCONT. (POSIX
> > 3.2.2.2)
> > */
> > forget_original_parent(tsk);
> > - exit_task_namespaces(tsk);
> >
> > write_lock_irq(&tasklist_lock);
> > if (group_dead)
> > @@ -795,6 +794,7 @@ void do_exit(long code)
> > exit_shm(tsk);
> > exit_files(tsk);
> > exit_fs(tsk);
> > + exit_task_namespaces(tsk);
> > exit_task_work(tsk);
I do not see any problems with this patch too... but still I am worried.
Even if fput() can work correctly after exit_task_namespaces(), this limits
the usage of task_work_add(). Probably this is fine, but can't we at least
discuss another change?
We can change fput() so that it can always work, even after exit_task_work(),
void fput(struct file *file)
{
if (atomic_long_dec_and_test(&file->f_count)) {
struct task_struct *task = current;
unsigned long flags;
file_sb_list_del(file);
if (likely(!in_interrupt() && !(task->flags &
PF_KTHREAD))) {
init_task_work(&file->f_u.fu_rcuhead, ____fput);
if (!task_work_add(task, &file->f_u.fu_rcuhead,
true))
return;
}
spin_lock_irqsave(&delayed_fput_lock, flags);
list_add(&file->f_u.fu_list, &delayed_fput_list);
schedule_work(&delayed_fput_work);
spin_unlock_irqrestore(&delayed_fput_lock, flags);
}
}
Al, what do you think?
Untested patch below.
Oleg.
--- x/fs/file_table.c
+++ x/fs/file_table.c
@@ -306,17 +306,19 @@ void fput(struct file *file)
{
if (atomic_long_dec_and_test(&file->f_count)) {
struct task_struct *task = current;
+ unsigned long flags;
+
file_sb_list_del(file);
- if (unlikely(in_interrupt() || task->flags & PF_KTHREAD)) {
- unsigned long flags;
- spin_lock_irqsave(&delayed_fput_lock, flags);
- list_add(&file->f_u.fu_list, &delayed_fput_list);
- schedule_work(&delayed_fput_work);
- spin_unlock_irqrestore(&delayed_fput_lock, flags);
- return;
+ if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) {
+ init_task_work(&file->f_u.fu_rcuhead, ____fput);
+ if (!task_work_add(task, &file->f_u.fu_rcuhead, true))
+ return;
}
- init_task_work(&file->f_u.fu_rcuhead, ____fput);
- task_work_add(task, &file->f_u.fu_rcuhead, true);
+
+ spin_lock_irqsave(&delayed_fput_lock, flags);
+ list_add(&file->f_u.fu_list, &delayed_fput_list);
+ schedule_work(&delayed_fput_work);
+ spin_unlock_irqrestore(&delayed_fput_lock, flags);
}
}
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