linux-kernel - Re: [PATCH v6 modules-next 1/2] module: Overwrite st_size instead of st

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Message-ID: <20181214205925.GA9656@linux-8ccs>
Date:   Fri, 14 Dec 2018 21:59:25 +0100
From:   Jessica Yu <jeyu@...nel.org>
To:     Vincent Whitchurch <vincent.whitchurch@...s.com>
Cc:     linux@...linux.org.uk, dave.martin@....com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Vincent Whitchurch <rabinv@...s.com>,
        Miroslav Benes <mbenes@...e.cz>
Subject: Re: [PATCH v6 modules-next 1/2] module: Overwrite st_size instead of
 st_info

+++ Vincent Whitchurch [14/12/18 17:05 +0100]:
>st_info is currently overwritten after relocation and used to store the
>elf_type().  However, we're going to need it fix kallsyms on ARM's
>Thumb-2 kernels, so preserve st_info and overwrite the st_size field
>instead.  st_size is neither used by the module core nor by any
>architecture.
>
>Reviewed-by: Miroslav Benes <mbenes@...e.cz>
>Reviewed-by: Dave Martin <Dave.Martin@....com>
>Signed-off-by: Vincent Whitchurch <vincent.whitchurch@...s.com>

Applied both. (Thanks for rebasing!)

Thanks,

Jessica

>---
>v6: Add Miroslav Benes' Reviewed-by
>v5: Add Dave Martin's Reviewed-by
>v4: Split out to separate patch.  Use st_size instead of st_other.
>v1-v3: See PATCH 2/2
>
> kernel/module.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
>diff --git a/kernel/module.c b/kernel/module.c
>index 1b5edf78694c..b36ff8a3d562 100644
>--- a/kernel/module.c
>+++ b/kernel/module.c
>@@ -2684,7 +2684,7 @@ static void add_kallsyms(struct module *mod, const struct load_info *info)
>
> 	/* Set types up while we still have access to sections. */
> 	for (i = 0; i < mod->kallsyms->num_symtab; i++)
>-		mod->kallsyms->symtab[i].st_info
>+		mod->kallsyms->symtab[i].st_size
> 			= elf_type(&mod->kallsyms->symtab[i], info);
>
> 	/* Now populate the cut down core kallsyms for after init. */
>@@ -4070,7 +4070,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
> 		kallsyms = rcu_dereference_sched(mod->kallsyms);
> 		if (symnum < kallsyms->num_symtab) {
> 			*value = kallsyms->symtab[symnum].st_value;
>-			*type = kallsyms->symtab[symnum].st_info;
>+			*type = kallsyms->symtab[symnum].st_size;
> 			strlcpy(name, kallsyms_symbol_name(kallsyms, symnum), KSYM_NAME_LEN);
> 			strlcpy(module_name, mod->name, MODULE_NAME_LEN);
> 			*exported = is_exported(name, *value, mod);
>-- 
>2.11.0
>