On Mon, 7 Jun 2021 21:18:54 +1200
Barry Song <song.bao.hua@xxxxxxxxxxxxx> wrote:
> free_insn_page() in x86 and s390 are same with the common weak function
> in kernel/kprobes.c.
> Plus, the comment "Recover page to RW mode before releasing it" in x86
> seems insensible to be there since resetting mapping is done by common
> code in vfree() of module_memfree().
> So drop these two duplicated strong functions and related comment, then
> mark the common one in kernel/kprobes.c strong.
Hm, OK. Actually riscv and arm64 uses __vmalloc() but anyway
since module_memfree() calls vfree(). So it has no problem.
Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Thank you,
>
> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> Signed-off-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
> ---
> -v2:
> remove free_insn_page in s390 as well and remove the __weak in common
> code according to Christoph's comment;
>
> arch/s390/kernel/kprobes.c | 5 -----
> arch/x86/kernel/kprobes/core.c | 6 ------
> kernel/kprobes.c | 2 +-
> 3 files changed, 1 insertion(+), 12 deletions(-)
>
> diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
> index aae24dc75df6..60cfbd24229b 100644
> --- a/arch/s390/kernel/kprobes.c
> +++ b/arch/s390/kernel/kprobes.c
> @@ -44,11 +44,6 @@ void *alloc_insn_page(void)
> return page;
> }
>
> -void free_insn_page(void *page)
> -{
> - module_memfree(page);
> -}
> -
> static void *alloc_s390_insn_page(void)
> {
> if (xchg(&insn_page_in_use, 1) == 1)
> 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)
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 745f08fdd7a6..ddb643f3879f 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -106,7 +106,7 @@ void __weak *alloc_insn_page(void)
> return module_alloc(PAGE_SIZE);
> }
>
> -void __weak free_insn_page(void *page)
> +void free_insn_page(void *page)
> {
> module_memfree(page);
> }
> --
> 2.25.1
>
--
Masami Hiramatsu <mhiramat@xxxxxxxxxx>
