2021-05-08 15:50:33

by Jisheng Zhang

Subject: [PATCH] riscv: kprobes: Fix build error when MMU=n

From: Jisheng Zhang <[email protected]>

lkp reported a randconfig failure:

arch/riscv/kernel/probes/kprobes.c:90:22: error: use of undeclared identifier 'PAGE_KERNEL_READ_EXEC'

We implemented the alloc_insn_page() to allocate PAGE_KERNEL_READ_EXEC
page for kprobes insn page for STRICT_MODULE_RWX. But if MMU=n, we
should fall back to the generic weak alloc_insn_page() by generic
kprobe subsystem.

Fixes: cdd1b2bd358f ("riscv: kprobes: Implement alloc_insn_page()")
Signed-off-by: Jisheng Zhang <[email protected]>
Reported-by: kernel test robot <[email protected]>
---
arch/riscv/kernel/probes/kprobes.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index 10b965c34536..15cc65ac7ca6 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -84,6 +84,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
return 0;
}

+#ifdef CONFIG_MMU
void *alloc_insn_page(void)
{
return __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, VMALLOC_END,
@@ -91,6 +92,7 @@ void *alloc_insn_page(void)
VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
__builtin_return_address(0));
}
+#endif

/* install breakpoint in text */
void __kprobes arch_arm_kprobe(struct kprobe *p)
--
2.31.0

2021-05-23 05:11:09

by Palmer Dabbelt

Subject: Re: [PATCH] riscv: kprobes: Fix build error when MMU=n

On Sat, 08 May 2021 08:43:47 PDT (-0700), [email protected] wrote:
> From: Jisheng Zhang <[email protected]>
>
> lkp reported a randconfig failure:
>
> arch/riscv/kernel/probes/kprobes.c:90:22: error: use of undeclared identifier 'PAGE_KERNEL_READ_EXEC'
>
> We implemented the alloc_insn_page() to allocate PAGE_KERNEL_READ_EXEC
> page for kprobes insn page for STRICT_MODULE_RWX. But if MMU=n, we
> should fall back to the generic weak alloc_insn_page() by generic
> kprobe subsystem.
>
> Fixes: cdd1b2bd358f ("riscv: kprobes: Implement alloc_insn_page()")
> Signed-off-by: Jisheng Zhang <[email protected]>
> Reported-by: kernel test robot <[email protected]>
> ---
> arch/riscv/kernel/probes/kprobes.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
> index 10b965c34536..15cc65ac7ca6 100644
> --- a/arch/riscv/kernel/probes/kprobes.c
> +++ b/arch/riscv/kernel/probes/kprobes.c
> @@ -84,6 +84,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
> return 0;
> }
>
> +#ifdef CONFIG_MMU
> void *alloc_insn_page(void)
> {
> return __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, VMALLOC_END,
> @@ -91,6 +92,7 @@ void *alloc_insn_page(void)
> VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
> __builtin_return_address(0));
> }
> +#endif
>
> /* install breakpoint in text */
> void __kprobes arch_arm_kprobe(struct kprobe *p)

Thanks, this is on fixes.