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From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>,
	Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>,
	linux-kernel@vger.kernel.org
Subject: [RFC PATCH 2/2] kprobes: Allow specifying names for certain blacklisted address ranges
Date: Thu, 29 Jun 2017 19:38:38 +0530	[thread overview]
Message-ID: <1a6d4df94ee8a61eda657b387f88d9ce1ec1fe3a.1498744665.git.naveen.n.rao@linux.vnet.ibm.com> (raw)
In-Reply-To: <cover.1498744665.git.naveen.n.rao@linux.vnet.ibm.com>
In-Reply-To: <cover.1498744665.git.naveen.n.rao@linux.vnet.ibm.com>

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@ubuntu:/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@ubuntu:/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]

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.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

  parent reply	other threads:[~2017-06-29 14:09 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-29 14:08 [RFC PATCH 0/2] Show kprobe blacklisted address ranges in debugfs Naveen N. Rao
2017-06-29 14:08 ` [RFC PATCH 1/2] kprobes: Simplify kprobe blacklist management Naveen N. Rao
2017-07-03  3:22   ` Masami Hiramatsu
2017-06-29 14:08 ` Naveen N. Rao [this message]
2017-07-03  3:22   ` [RFC PATCH 2/2] kprobes: Allow specifying names for certain blacklisted address ranges Masami Hiramatsu

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