Subject: [PATCH] x86/kprobes: remove free_insn_page since it is same with the common weak function

free_insn_page() in x86 is same with the common weak function in
kernel/kprobes.c. Plus, its comment "Recover page to RW mode before
releasing it" seems insensible to be there since resetting mapping
is done by common code in vfree() of module_memfree().
So drop the strong function and its comment in x86 totally.

Signed-off-by: Barry Song <[email protected]>
---
arch/x86/kernel/kprobes/core.c | 6 ------
1 file changed, 6 deletions(-)

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index d3d65545cb8b..3bce67d3a03c 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -422,12 +422,6 @@ void *alloc_insn_page(void)
return page;
}

-/* Recover page to RW mode before releasing it */
-void free_insn_page(void *page)
-{
- module_memfree(page);
-}
-
/* Kprobe x86 instruction emulation - only regs->ip or IF flag modifiers */

static void kprobe_emulate_ifmodifiers(struct kprobe *p, struct pt_regs *regs)
--
2.25.1


2021-06-07 08:20:58

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [PATCH] x86/kprobes: remove free_insn_page since it is same with the common weak function

On Tue, Jun 01, 2021 at 04:08:56PM +1200, Barry Song wrote:
> free_insn_page() in x86 is same with the common weak function in
> kernel/kprobes.c. Plus, its comment "Recover page to RW mode before
> releasing it" seems insensible to be there since resetting mapping
> is done by common code in vfree() of module_memfree().
> So drop the strong function and its comment in x86 totally.
>
> Signed-off-by: Barry Song <[email protected]>

It also is the same for s390, so please remove that as well and remove
the __weak.