2019-04-26 07:33:50

by Nadav Amit

Subject: [PATCH v5 20/23] x86/kprobes: Use vmalloc special flag

From: Rick Edgecombe <[email protected]>

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 <[email protected]>
Signed-off-by: Rick Edgecombe <[email protected]>
---
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 1591852d3ac4..136695e4434a 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

2019-04-30 11:32:15

by tip-bot for Vasyl Gomonovych

Subject: [tip:x86/mm] x86/kprobes: Use vmalloc special flag

Commit-ID: 241a1f22380646bc4d1dd18e5bc246877513da68
Gitweb: https://git.kernel.org/tip/241a1f22380646bc4d1dd18e5bc246877513da68
Author: Rick Edgecombe <[email protected]>
AuthorDate: Thu, 25 Apr 2019 17:11:40 -0700
Committer: Ingo Molnar <[email protected]>
CommitDate: Tue, 30 Apr 2019 12:38:01 +0200

x86/kprobes: Use vmalloc special flag

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.

Signed-off-by: Rick Edgecombe <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Nadav Amit <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
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 06058c44ab57..800593f4ddf7 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);
}