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Date: Mon, 3 Jul 2017 12:22:38 +0900
From: Masami Hiramatsu <mhiramat@...nel.org>
To: "Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@...nel.org>,
Ananth N Mavinakayanahalli <ananth@...ux.vnet.ibm.com>,
linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 2/2] kprobes: Allow specifying names for certain
blacklisted address ranges
On Thu, 29 Jun 2017 19:38:38 +0530
"Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com> wrote:
> This allows us to provide meaningful names for certain address ranges
> that are blacklisted such as those with __kprobes annotation, kernel
> entry text, and so on. For such ranges, using the symbol/function name
> at the start of the range is misleading.
>
> On a powerpc64le system, before patch:
> root@...ntu:/sys/kernel/debug# tail kprobes/blacklist
> 0xc00000000022d500-0xc00000000022d580 print_type_s64
> 0xc00000000022d480-0xc00000000022d500 print_type_s32
> 0xc00000000022d400-0xc00000000022d480 print_type_s16
> 0xc00000000022d380-0xc00000000022d400 print_type_s8
> 0xc00000000022d300-0xc00000000022d380 print_type_u64
> 0xc00000000022d280-0xc00000000022d300 print_type_u32
> 0xc00000000022d200-0xc00000000022d280 print_type_u16
> 0xc00000000022d180-0xc00000000022d200 print_type_u8
> 0xc0000000009ed778-0xc0000000009ed778 __irqentry_text_end
> 0xc000000000000000-0xc000000000008000 start_first_256B
>
> After patch:
> root@...ntu:/sys/kernel/debug# tail kprobes/blacklist
> 0xc00000000022d540-0xc00000000022d5c0 print_type_s64
> 0xc00000000022d4c0-0xc00000000022d540 print_type_s32
> 0xc00000000022d440-0xc00000000022d4c0 print_type_s16
> 0xc00000000022d3c0-0xc00000000022d440 print_type_s8
> 0xc00000000022d340-0xc00000000022d3c0 print_type_u64
> 0xc00000000022d2c0-0xc00000000022d340 print_type_u32
> 0xc00000000022d240-0xc00000000022d2c0 print_type_u16
> 0xc00000000022d1c0-0xc00000000022d240 print_type_u8
> 0xc0000000009ed7b8-0xc0000000009ed7b8 [__kprobes]
> 0xc000000000000000-0xc000000000008000 [__exceptions]
Looks good to me :)
Acked-by: Masami Hiramatsu <mhiramat@...nel.org>
Thanks!
>
> Signed-off-by: Naveen N. Rao <naveen.n.rao@...ux.vnet.ibm.com>
> ---
> arch/arm64/kernel/probes/kprobes.c | 10 +++++-----
> arch/powerpc/kernel/kprobes.c | 4 ++--
> arch/x86/kernel/kprobes/core.c | 4 ++--
> include/linux/kprobes.h | 3 ++-
> kernel/kprobes.c | 17 ++++++++++++-----
> 5 files changed, 23 insertions(+), 15 deletions(-)
>
> diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
> index 7f453a71b5a8..340325ec97c6 100644
> --- a/arch/arm64/kernel/probes/kprobes.c
> +++ b/arch/arm64/kernel/probes/kprobes.c
> @@ -544,17 +544,17 @@ bool arch_within_kprobe_blacklist(unsigned long addr)
> void __init arch_populate_kprobe_blacklist(void)
> {
> insert_kprobe_blacklist((unsigned long)__kprobes_text_start,
> - (unsigned long)__kprobes_text_end);
> + (unsigned long)__kprobes_text_end, "[__kprobes]");
> insert_kprobe_blacklist((unsigned long)__entry_text_start,
> - (unsigned long)__entry_text_end);
> + (unsigned long)__entry_text_end, "[__entry]");
> insert_kprobe_blacklist((unsigned long)__idmap_text_start,
> - (unsigned long)__idmap_text_end);
> + (unsigned long)__idmap_text_end, "[__idmap]");
>
> if (!is_kernel_in_hyp_mode()) {
> insert_kprobe_blacklist((unsigned long)__hyp_text_start,
> - (unsigned long)__hyp_text_end);
> + (unsigned long)__hyp_text_end, "[__hyp]");
> insert_kprobe_blacklist((unsigned long)__hyp_idmap_text_start,
> - (unsigned long)__hyp_idmap_text_end);
> + (unsigned long)__hyp_idmap_text_end, "[__hyp_idmap]");
> }
> }
>
> diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
> index f707e42b3482..1b873e19d29b 100644
> --- a/arch/powerpc/kernel/kprobes.c
> +++ b/arch/powerpc/kernel/kprobes.c
> @@ -52,9 +52,9 @@ int is_current_kprobe_addr(unsigned long addr)
> void __init arch_populate_kprobe_blacklist(void)
> {
> insert_kprobe_blacklist((unsigned long)__kprobes_text_start,
> - (unsigned long)__kprobes_text_end);
> + (unsigned long)__kprobes_text_end, "[__kprobes]");
> insert_kprobe_blacklist((unsigned long)_stext,
> - (unsigned long)__head_end);
> + (unsigned long)__head_end, "[__exceptions]");
> }
>
> kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset)
> diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
> index 4a5fc04b3e92..20e71d783bcf 100644
> --- a/arch/x86/kernel/kprobes/core.c
> +++ b/arch/x86/kernel/kprobes/core.c
> @@ -1144,9 +1144,9 @@ NOKPROBE_SYMBOL(longjmp_break_handler);
> void __init arch_populate_kprobe_blacklist(void)
> {
> insert_kprobe_blacklist((unsigned long)__kprobes_text_start,
> - (unsigned long)__kprobes_text_end);
> + (unsigned long)__kprobes_text_end, "[__kprobes]");
> insert_kprobe_blacklist((unsigned long)__entry_text_start,
> - (unsigned long)__entry_text_end);
> + (unsigned long)__entry_text_end, "[__entry]");
> }
>
> int __init arch_init_kprobes(void)
> diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
> index 6d931ea0604e..05a4f2619cdc 100644
> --- a/include/linux/kprobes.h
> +++ b/include/linux/kprobes.h
> @@ -210,6 +210,7 @@ struct kprobe_blacklist_entry {
> struct list_head list;
> unsigned long start_addr;
> unsigned long end_addr;
> + char *name;
> };
>
> #ifdef CONFIG_KPROBES
> @@ -271,7 +272,7 @@ extern bool arch_function_offset_within_entry(unsigned long offset);
> extern bool function_offset_within_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset);
>
> extern bool within_kprobe_blacklist(unsigned long addr);
> -extern void insert_kprobe_blacklist(unsigned long start, unsigned long end);
> +extern void insert_kprobe_blacklist(unsigned long start, unsigned long end, const char *name);
> extern void arch_populate_kprobe_blacklist(void);
>
> struct kprobe_insn_cache {
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 8ddbee01ce01..fcb1765de49e 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -2125,7 +2125,8 @@ NOKPROBE_SYMBOL(dump_kprobe);
> extern unsigned long __start_kprobe_blacklist[];
> extern unsigned long __stop_kprobe_blacklist[];
>
> -void __init insert_kprobe_blacklist(unsigned long start, unsigned long end)
> +void __init insert_kprobe_blacklist(unsigned long start, unsigned long end,
> + const char *name)
> {
> struct kprobe_blacklist_entry *ent;
>
> @@ -2137,6 +2138,7 @@ void __init insert_kprobe_blacklist(unsigned long start, unsigned long end)
>
> ent->start_addr = start;
> ent->end_addr = end;
> + ent->name = kstrdup(name, GFP_KERNEL);
> INIT_LIST_HEAD(&ent->list);
> list_add_tail(&ent->list, &kprobe_blacklist);
> }
> @@ -2145,7 +2147,7 @@ void __weak __init arch_populate_kprobe_blacklist(void)
> {
> /* The __kprobes marked functions and entry code must not be probed */
> insert_kprobe_blacklist((unsigned long)__kprobes_text_start,
> - (unsigned long)__kprobes_text_end);
> + (unsigned long)__kprobes_text_end, "[__kprobes]");
> }
>
> static void __init populate_kprobe_blacklist(void)
> @@ -2165,7 +2167,7 @@ static void __init populate_kprobe_blacklist(void)
> continue;
> }
>
> - insert_kprobe_blacklist(entry, entry + size);
> + insert_kprobe_blacklist(entry, entry + size, NULL);
> }
>
> /* Let architectures add their own entries as well */
> @@ -2378,8 +2380,13 @@ static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
> struct kprobe_blacklist_entry *ent =
> list_entry(v, struct kprobe_blacklist_entry, list);
>
> - seq_printf(m, "0x%p-0x%p\t%ps\n", (void *)ent->start_addr,
> - (void *)ent->end_addr, (void *)ent->start_addr);
> + if (ent->name)
> + seq_printf(m, "0x%p-0x%p\t%s\n", (void *)ent->start_addr,
> + (void *)ent->end_addr, ent->name);
> + else
> + seq_printf(m, "0x%p-0x%p\t%ps\n", (void *)ent->start_addr,
> + (void *)ent->end_addr, (void *)ent->start_addr);
> +
> return 0;
> }
>
> --
> 2.13.1
>
--
Masami Hiramatsu <mhiramat@...nel.org>
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