From: Nathan Chancellor <nathan@kernel.org>
To: Kees Cook <kees@kernel.org>
Cc: Youling Tang <tangyouling@kylinos.cn>,
Huacai Chen <chenhuacai@loongson.cn>,
Huacai Chen <chenhuacai@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Pasha Tatashin <pasha.tatashin@soleen.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
David Disseldorp <ddiss@suse.de>,
Qun-Wei Lin <qun-wei.lin@mediatek.com>,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH] sched/task_stack: Add missing const qualifier to end_of_stack()
Date: Sun, 27 Jul 2025 08:50:47 -0700 [thread overview]
Message-ID: <20250727155047.GA1183915@ax162> (raw)
In-Reply-To: <20250726210641.work.114-kees@kernel.org>
On Sat, Jul 26, 2025 at 02:06:46PM -0700, Kees Cook wrote:
> Add missing const qualifier to the non-CONFIG_THREAD_INFO_IN_TASK
> version of end_of_stack() to match the CONFIG_THREAD_INFO_IN_TASK
> version. Fixes a warning with CONFIG_KSTACK_ERASE=y on archs that don't
> select THREAD_INFO_IN_TASK (such as LoongArch):
>
> error: passing 'const struct task_struct *' to parameter of type 'struct task_struct *' discards qualifiers
>
> The stackleak_task_low_bound() function correctly uses a const task
> parameter, but the legacy end_of_stack() prototype didn't like that.
>
> Build tested on loongarch (with CONFIG_KSTACK_ERASE=y) and m68k
> (with CONFIG_DEBUG_STACK_USAGE=y).
>
> Fixes: a45728fd4120 ("LoongArch: Enable HAVE_ARCH_STACKLEAK")
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Closes: https://lore.kernel.org/all/20250726004313.GA3650901@ax162
> Cc: Youling Tang <tangyouling@kylinos.cn>
> Cc: Huacai Chen <chenhuacai@loongson.cn>
> Signed-off-by: Kees Cook <kees@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
> ---
> include/linux/sched/task_stack.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/sched/task_stack.h b/include/linux/sched/task_stack.h
> index 85c5a6392e02..1fab7e9043a3 100644
> --- a/include/linux/sched/task_stack.h
> +++ b/include/linux/sched/task_stack.h
> @@ -53,7 +53,7 @@ static inline void setup_thread_stack(struct task_struct *p, struct task_struct
> * When the stack grows up, this is the highest address.
> * Beyond that position, we corrupt data on the next page.
> */
> -static inline unsigned long *end_of_stack(struct task_struct *p)
> +static inline unsigned long *end_of_stack(const struct task_struct *p)
> {
> #ifdef CONFIG_STACK_GROWSUP
> return (unsigned long *)((unsigned long)task_thread_info(p) + THREAD_SIZE) - 1;
> --
> 2.34.1
>
prev parent reply other threads:[~2025-07-27 15:50 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-26 21:06 [PATCH] sched/task_stack: Add missing const qualifier to end_of_stack() Kees Cook
2025-07-27 15:50 ` Nathan Chancellor [this message]
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