Re: [PATCH 2/2] mm/linux-next: Fix rcu locking in vm_is_stack

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]


On Wed, Mar 7, 2012 at 9:08 PM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
> Once again. You have the task_struct *task. It exits,
> but task->thread_group->next still points to another thread T. Now suppose
> that T exits too. But task->thread_group->next was not changed, it still
> points to T. RCU grace period passes, T is freed.
>
> After that you take rcu_read_lock(), but it is too late! >next points to
> the already freed/reused memory. How can list_first_entry_rcu() help?

Ahh, I completely misunderstood your point. Thanks for the detailed explanation.

> And. Imho it is not good to have the (afaics exactly?) same code in
> mm/nommu.c, even with the same names. Why it is not possible to make
> a single definition?

Yes it is the same code. I put the code in both memory.c and nommu.c
because I thought they fit in there logically. I can find a common
place for it.



-- 
Siddhesh Poyarekar
http://siddhesh.in
--
To unsubscribe from this list: send the line "unsubscribe linux-next" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Photo]     [Yosemite News]    [Yosemite Photos]    [Free Online Dating]     [Linux Kernel]     [Linux SCSI]     [XFree86]

Add to Google Powered by Linux