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SubjectRe: [PATCH] x86/hw_breakpoints, kprobes: Remove kprobes ifdeffery
On Sun, 27 Jan 2019 14:12:37 +0100
Borislav Petkov <bp@alien8.de> wrote:

> From: Borislav Petkov <bp@suse.de>
>
> Remove the ifdeffery in the breakpoint parsing arch_build_bp_info() by
> adding a within_kprobe_blacklist() stub for the !CONFIG_KPROBES case.
>
> It is returning true when kprobes are not enabled to mean that any
> address is within the kprobes blacklist on such kernels and thus not
> allow kernel breakpoints on non-kprobes kernels.
>

This looks good to me.

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Thank you Borislav!!

> Signed-off-by: Borislav Petkov <bp@suse.de>
> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Frederic Weisbecker <frederic@kernel.org>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Masami Hiramatsu <mhiramat@kernel.org>
> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> ---
> arch/x86/kernel/hw_breakpoint.c | 4 ----
> include/linux/kprobes.h | 5 +++++
> 2 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c
> index 7d6f91f2869a..ff9bfd40429e 100644
> --- a/arch/x86/kernel/hw_breakpoint.c
> +++ b/arch/x86/kernel/hw_breakpoint.c
> @@ -261,12 +261,8 @@ static int arch_build_bp_info(struct perf_event *bp,
> * allow kernel breakpoints at all.
> */
> if (attr->bp_addr >= TASK_SIZE_MAX) {
> -#ifdef CONFIG_KPROBES
> if (within_kprobe_blacklist(attr->bp_addr))
> return -EINVAL;
> -#else
> - return -EINVAL;
> -#endif
> }
>
> hw->type = X86_BREAKPOINT_EXECUTE;
> diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
> index e07e91daaacc..201f0f2683f2 100644
> --- a/include/linux/kprobes.h
> +++ b/include/linux/kprobes.h
> @@ -442,6 +442,11 @@ static inline int enable_kprobe(struct kprobe *kp)
> {
> return -ENOSYS;
> }
> +
> +static inline bool within_kprobe_blacklist(unsigned long addr)
> +{
> + return true;
> +}
> #endif /* CONFIG_KPROBES */
> static inline int disable_kretprobe(struct kretprobe *rp)
> {
> --
> 2.19.1
>


--
Masami Hiramatsu <mhiramat@kernel.org>

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