From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Andy Lutomirski <luto@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org,
Ben Segall <bsegall@google.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Ingo Molnar <mingo@redhat.com>,
Juri Lelli <juri.lelli@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Vincent Guittot <vincent.guittot@linaro.org>
Subject: Re: [PATCH 2/8] kernel/fork: Duplicate task_struct before stack allocation.
Date: Mon, 14 Feb 2022 12:39:05 +0100 [thread overview]
Message-ID: <Ygo/WWSQHFkGn095@linutronix.de> (raw)
In-Reply-To: <8340d413-4951-5e62-ef5f-f396523edac7@kernel.org>
On 2022-02-11 15:42:38 [-0800], Andy Lutomirski wrote:
> On 1/25/22 07:26, Sebastian Andrzej Siewior wrote:
> > alloc_thread_stack_node() already populates the task_struct::stack
> > member except on IA64. The stack pointer is saved and populated again
> > because IA64 needs it and arch_dup_task_struct() overwrites it.
>
> I understand the problem, I think.
>
> >
> > Allocate thread's stack after task_struct has been duplicated as a
> > preparation.
> >
>
> But I don't understand this. How does this patch relate to the problem?
So I duplicate the task-struct, assign the stack pointer in
alloc_thread_stack_node() with no need to update the stack pointer
later. Otherwise arch_dup_task_struct() would reset the pointer.
> Also, you appear to be missing a change to the free_stack and free_tsk code
> at the end of dup_task_struct().
It looks right. What am I missing?
Sebastian
next prev parent reply other threads:[~2022-02-14 11:45 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-25 15:26 [PATCH REPOST 0/8] kernel/fork: Move thread stack free otu of the scheduler path Sebastian Andrzej Siewior
2022-01-25 15:26 ` [PATCH 1/8] kernel/fork: Redo ifdefs around task's handling Sebastian Andrzej Siewior
2022-01-25 15:26 ` [PATCH 2/8] kernel/fork: Duplicate task_struct before stack allocation Sebastian Andrzej Siewior
2022-02-11 23:42 ` Andy Lutomirski
2022-02-14 11:39 ` Sebastian Andrzej Siewior [this message]
2022-01-25 15:26 ` [PATCH 3/8] kernel/fork, IA64: Provide a alloc_thread_stack_node() for IA64 Sebastian Andrzej Siewior
2022-02-14 18:00 ` Sebastian Andrzej Siewior
2022-01-25 15:26 ` [PATCH 4/8] kernel/fork: Don't assign the stack pointer in dup_task_struct() Sebastian Andrzej Siewior
2022-01-25 15:26 ` [PATCH 5/8] kernel/fork: Move memcg_charge_kernel_stack() into CONFIG_VMAP_STACK Sebastian Andrzej Siewior
2022-01-25 15:26 ` [PATCH 6/8] kernel/fork: Move task stack account to do_exit() Sebastian Andrzej Siewior
2022-02-11 23:43 ` Andy Lutomirski
2022-01-25 15:26 ` [PATCH 7/8] kernel/fork: Only cache the VMAP stack in finish_task_switch() Sebastian Andrzej Siewior
2022-02-11 23:55 ` Andy Lutomirski
2022-02-14 12:10 ` Sebastian Andrzej Siewior
2022-02-14 12:24 ` Sebastian Andrzej Siewior
2022-02-14 16:54 ` Sebastian Andrzej Siewior
2022-02-14 17:48 ` Sebastian Andrzej Siewior
2022-02-14 18:15 ` [PATCH v2 " Sebastian Andrzej Siewior
2022-01-25 15:26 ` [PATCH 8/8] kernel/fork: Use IS_ENABLED() in account_kernel_stack() Sebastian Andrzej Siewior
2022-02-08 17:10 ` [PATCH REPOST 0/8] kernel/fork: Move thread stack free otu of the scheduler path Sebastian Andrzej Siewior
-- strict thread matches above, loose matches on Subject: below --
2021-11-18 14:34 [PATCH " Sebastian Andrzej Siewior
2021-11-18 14:34 ` [PATCH 2/8] kernel/fork: Duplicate task_struct before stack allocation Sebastian Andrzej Siewior
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