linux-kernel - [PATCH v2 8/9] livepatch: Remove module_disable

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Message-Id: <11723c83107129047d3b9e5d5a026b14dce6d391.1587131959.git.jpoimboe@redhat.com>
Date:   Fri, 17 Apr 2020 09:04:33 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     live-patching@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Jessica Yu <jeyu@...nel.org>
Subject: [PATCH v2 8/9] livepatch: Remove module_disable_ro() usage

With arch_klp_init_object_loaded() gone, and apply_relocate_add() now
using text_poke(), livepatch no longer needs to use module_disable_ro().

The text_mutex usage can also be removed -- its purpose was to protect
against module permission change races.

Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
---
 kernel/livepatch/core.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index a090185e8689..3ff886b911ae 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -767,10 +767,6 @@ static int klp_init_object_loaded(struct klp_patch *patch,
 	struct klp_modinfo *info = patch->mod->klp_info;
 
 	if (klp_is_module(obj)) {
-
-		mutex_lock(&text_mutex);
-		module_disable_ro(patch->mod);
-
 		/*
 		 * Only write module-specific relocations here
 		 * (.klp.rela.{module}.*).  vmlinux-specific relocations were
@@ -782,10 +778,6 @@ static int klp_init_object_loaded(struct klp_patch *patch,
 					    patch->mod->core_kallsyms.strtab,
 					    info->symndx, patch->mod,
 					    obj->name);
-
-		module_enable_ro(patch->mod, true);
-		mutex_unlock(&text_mutex);
-
 		if (ret)
 			return ret;
 	}
-- 
2.21.1