[patch 03/38] x86/modules: Set VM_FLUSH_RESET_PERMS in module_alloc()

Thomas Gleixner
2022-07-16T23:17:26Z

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@linutronix.de>
---
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
@@ -412,8 +412,6 @@ 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;