[PATCH v3 19/20] x86/kprobes: Use vmalloc special flag
From: Rick Edgecombe
Date: Thu Feb 21 2019 - 18:51:27 EST
Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special
permissioned memory in vmalloc and remove places where memory was set NX
and RW before freeing which is no longer needed.
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
---
arch/x86/kernel/kprobes/core.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 98c671e89889..8b56935d7b53 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -434,6 +434,7 @@ 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.
@@ -452,12 +453,6 @@ void *alloc_insn_page(void)
/* Recover page to RW mode before releasing it */
void free_insn_page(void *page)
{
- /*
- * First make the page non-executable, and only then make it writable to
- * prevent it from being W+X in between.
- */
- set_memory_nx((unsigned long)page, 1);
- set_memory_rw((unsigned long)page, 1);
module_memfree(page);
}
--
2.17.1