linux-kernel - Re: [PATCH] LoongArch: Fix lockdep static memory detection

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Message-ID: <9d0cb447-2556-4609-a96f-13875ddeeda3@roeck-us.net>
Date:   Tue, 12 Sep 2023 13:31:23 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Helge Deller <deller@....de>
Cc:     Huacai Chen <chenhuacai@...nel.org>,
        WANG Xuerui <kernel@...0n.name>, loongarch@...ts.linux.dev,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] LoongArch: Fix lockdep static memory detection

On Tue, Sep 12, 2023 at 09:18:37PM +0200, Helge Deller wrote:
> Since commit 0a6b58c5cd0d ("lockdep: fix static memory detection even
> more") the lockdep code uses is_kernel_core_data(), is_kernel_rodata()
> and init_section_contains() to verify if a lock is located inside a
> kernel static data section.
> 
> This change triggers a failure on LoongArch, for which the vmlinux.lds.S
> script misses to put the locks (as part of in the .data.rel symbols)
> into the Linux data section.
> This patch fixes the lockdep problem by moving *(.data.rel*) symbols
> into the kernel data section (from _sdata to _edata).
> 
> Additionally, move other wrongly assigned symbols too:
> - altinstructions into the _initdata section,
> - PLT symbols behind the read-only section, and
> - *(.la_abs) into the data section.
> 
> Signed-off-by: Helge Deller <deller@....de>
> Reported-by: Guenter Roeck <linux@...ck-us.net>
> Fixes: 0a6b58c5cd0d ("lockdep: fix static memory detection even more")
> Cc: stable <stable@...nel.org> # v6.4+

Tested-by: Guenter Roeck <linux@...ck-us.net>

> 
> diff --git a/arch/loongarch/kernel/vmlinux.lds.S b/arch/loongarch/kernel/vmlinux.lds.S
> index b1686afcf876..bb2ec86f37a8 100644
> --- a/arch/loongarch/kernel/vmlinux.lds.S
> +++ b/arch/loongarch/kernel/vmlinux.lds.S
> @@ -53,33 +53,6 @@ SECTIONS
>  	. = ALIGN(PECOFF_SEGMENT_ALIGN);
>  	_etext = .;
>  
> -	/*
> -	 * struct alt_inst entries. From the header (alternative.h):
> -	 * "Alternative instructions for different CPU types or capabilities"
> -	 * Think locking instructions on spinlocks.
> -	 */
> -	. = ALIGN(4);
> -	.altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
> -		__alt_instructions = .;
> -		*(.altinstructions)
> -		__alt_instructions_end = .;
> -	}
> -
> -#ifdef CONFIG_RELOCATABLE
> -	. = ALIGN(8);
> -	.la_abs : AT(ADDR(.la_abs) - LOAD_OFFSET) {
> -		__la_abs_begin = .;
> -		*(.la_abs)
> -		__la_abs_end = .;
> -	}
> -#endif
> -
> -	.got : ALIGN(16) { *(.got) }
> -	.plt : ALIGN(16) { *(.plt) }
> -	.got.plt : ALIGN(16) { *(.got.plt) }
> -
> -	.data.rel : { *(.data.rel*) }
> -
>  	. = ALIGN(PECOFF_SEGMENT_ALIGN);
>  	__init_begin = .;
>  	__inittext_begin = .;
> @@ -94,6 +67,18 @@ SECTIONS
>  
>  	__initdata_begin = .;
>  
> +	/*
> +	 * struct alt_inst entries. From the header (alternative.h):
> +	 * "Alternative instructions for different CPU types or capabilities"
> +	 * Think locking instructions on spinlocks.
> +	 */
> +	. = ALIGN(4);
> +	.altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
> +		__alt_instructions = .;
> +		*(.altinstructions)
> +		__alt_instructions_end = .;
> +	}
> +
>  	INIT_DATA_SECTION(16)
>  	.exit.data : {
>  		EXIT_DATA
> @@ -113,6 +98,11 @@ SECTIONS
>  
>  	_sdata = .;
>  	RO_DATA(4096)
> +
> +	.got : ALIGN(16) { *(.got) }
> +	.plt : ALIGN(16) { *(.plt) }
> +	.got.plt : ALIGN(16) { *(.got.plt) }
> +
>  	RW_DATA(1 << CONFIG_L1_CACHE_SHIFT, PAGE_SIZE, THREAD_SIZE)
>  
>  	.rela.dyn : ALIGN(8) {
> @@ -121,6 +111,17 @@ SECTIONS
>  		__rela_dyn_end = .;
>  	}
>  
> +	.data.rel : { *(.data.rel*) }
> +
> +#ifdef CONFIG_RELOCATABLE
> +	. = ALIGN(8);
> +	.la_abs : AT(ADDR(.la_abs) - LOAD_OFFSET) {
> +		__la_abs_begin = .;
> +		*(.la_abs)
> +		__la_abs_end = .;
> +	}
> +#endif
> +
>  	.sdata : {
>  		*(.sdata)
>  	}