linux-kernel - [PATCH v2 05/59] x86/modules: Set VM_FLUSH_RESET_PERMS in module

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Date:   Fri, 02 Sep 2022 15:06:30 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     linux-kernel@...r.kernel.org, peterz@...radead.org, x86@...nel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Josh Poimboeuf <jpoimboe@...nel.org>,
        Andrew Cooper <Andrew.Cooper3@...rix.com>,
        Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
        Johannes Wikner <kwikner@...z.ch>,
        Alyssa Milburn <alyssa.milburn@...ux.intel.com>,
        Jann Horn <jannh@...gle.com>, "H.J. Lu" <hjl.tools@...il.com>,
        Joao Moreira <joao.moreira@...el.com>,
        Joseph Nuzman <joseph.nuzman@...el.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Juergen Gross <jgross@...e.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        K Prateek Nayak <kprateek.nayak@....com>,
        Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH v2 05/59] x86/modules: Set VM_FLUSH_RESET_PERMS in module_alloc()

From: Thomas Gleixner <tglx@...utronix.de>

Instead of resetting permissions all over the place when freeing module
memory tell the vmalloc code to do so. Avoids the exercise for the next
upcoming user.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/x86/kernel/ftrace.c       |    2 --
 arch/x86/kernel/kprobes/core.c |    1 -
 arch/x86/kernel/module.c       |    9 +++++----
 3 files changed, 5 insertions(+), 7 deletions(-)

--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -413,8 +413,6 @@ create_trampoline(struct ftrace_ops *ops
 	/* ALLOC_TRAMP flags lets us know we created it */
 	ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
 
-	set_vm_flush_reset_perms(trampoline);
-
 	if (likely(system_state != SYSTEM_BOOTING))
 		set_memory_ro((unsigned long)trampoline, npages);
 	set_memory_x((unsigned long)trampoline, npages);
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -416,7 +416,6 @@ void *alloc_insn_page(void)
 	if (!page)
 		return NULL;
 
-	set_vm_flush_reset_perms(page);
 	/*
 	 * First make the page read-only, and only then make it executable to
 	 * prevent it from being W+X in between.
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -74,10 +74,11 @@ void *module_alloc(unsigned long size)
 		return NULL;
 
 	p = __vmalloc_node_range(size, MODULE_ALIGN,
-				    MODULES_VADDR + get_module_load_offset(),
-				    MODULES_END, gfp_mask,
-				    PAGE_KERNEL, VM_DEFER_KMEMLEAK, NUMA_NO_NODE,
-				    __builtin_return_address(0));
+				 MODULES_VADDR + get_module_load_offset(),
+				 MODULES_END, gfp_mask, PAGE_KERNEL,
+				 VM_FLUSH_RESET_PERMS | VM_DEFER_KMEMLEAK,
+				 NUMA_NO_NODE, __builtin_return_address(0));
+
 	if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 0)) {
 		vfree(p);
 		return NULL;