Re: BUG: Use after free in detach_pid

[Andrew Morton]

Manfred Spraul <[e-mail]> wrote:
>
> You mentioned that the last detach_pid() within __unhash_process oopsed. That means the reference count of the task structure was off by one, and the
> 	put_task_struct(pid->task)
> within 
> 	detach_pid(p,PIDTYPE_PGID);
> freed the task structure.
> 

Might be related to http://bugme.osdl.org/show_bug.cgi?id=482
in which someone did put_task_struct() on an already-freed task_struct.

And that was a uniprocessor without pgcl gunk.

It is not known whether preemption was enabled?