Re: Patch "LoongArch/orc: Use RCU in all users of __module_address()." has been added to the 6.12-stable tree

Re: Patch "LoongArch/orc: Use RCU in all users of __module_address()." has been added to the 6.12-stable tree

[Huacai Chen]

Hi, Sasha,

On Mon, Mar 9, 2026 at 12:42 AM Sasha Levin <sashal@kernel.org> wrote:
>
> This is a note to let you know that I've just added the patch titled
>
>     LoongArch/orc: Use RCU in all users of __module_address().
>
> to the 6.12-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
>
> The filename of the patch is:
>      loongarch-orc-use-rcu-in-all-users-of-__module_addre.patch
> and it can be found in the queue-6.12 subdirectory.
>
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable@vger.kernel.org> know about it.
>
Is this really needed in 6.12?

Huacai
>
>
> commit cb7c7e4265d8d6fbba83f1d4df9a028837702e06
> Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Date:   Wed Jan 8 10:04:47 2025 +0100
>
>     LoongArch/orc: Use RCU in all users of __module_address().
>
>     [ Upstream commit f99d27d9feb755aee9350fc89f57814d7e1b4880 ]
>
>     __module_address() can be invoked within a RCU section, there is no
>     requirement to have preemption disabled.
>
>     Replace the preempt_disable() section around __module_address() with
>     RCU.
>
>     Cc: Huacai Chen <chenhuacai@kernel.org>
>     Cc: WANG Xuerui <kernel@xen0n.name>
>     Cc: loongarch@lists.linux.dev
>     Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
>     Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
>     Link: https://lore.kernel.org/r/20250108090457.512198-19-bigeasy@linutronix.de
>     Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
>     Stable-dep-of: 055c7e75190e ("LoongArch: Handle percpu handler address for ORC unwinder")
>     Signed-off-by: Sasha Levin <sashal@kernel.org>
>
> diff --git a/arch/loongarch/kernel/unwind_orc.c b/arch/loongarch/kernel/unwind_orc.c
> index 471652c0c8653..59809c3406c03 100644
> --- a/arch/loongarch/kernel/unwind_orc.c
> +++ b/arch/loongarch/kernel/unwind_orc.c
> @@ -399,7 +399,7 @@ bool unwind_next_frame(struct unwind_state *state)
>                 return false;
>
>         /* Don't let modules unload while we're reading their ORC data. */
> -       preempt_disable();
> +       guard(rcu)();
>
>         if (is_entry_func(state->pc))
>                 goto end;
> @@ -514,14 +514,12 @@ bool unwind_next_frame(struct unwind_state *state)
>         if (!__kernel_text_address(state->pc))
>                 goto err;
>
> -       preempt_enable();
>         return true;
>
>  err:
>         state->error = true;
>
>  end:
> -       preempt_enable();
>         state->stack_info.type = STACK_TYPE_UNKNOWN;
>         return false;
>  }