[PATCH v3 0/4] kprobes: split blacklist into common and arch

[PATCH v3 0/4] kprobes: split blacklist into common and arch

[Oskar Andero]

Hi,

This is version 3 of the patch-set for splitting arch and common kprobe
blackpoints.

Changes since last version are:
- 1/4: Add write memory barrier at blacklist initialization.
- 1/4: Change kprobe_blacklist_initialized type to boolean.
- 2/4: Fix racing of kprobe_blacklist.
- 2/4: Define arch_kprobes_blacksyms.* as __weak symbols.

-Oskar

Björn Davidsson (1):
  kprobes: move x86-specific blacklist symbols to arch directory

Oskar Andero (2):
  kprobes: split blacklist into common and arch
  kprobes: replace printk with pr_-functions

Toby Collett (1):
  kprobes: delay blacklist symbol lookup until we actually need it

 arch/x86/kernel/kprobes/core.c |   7 ++
 kernel/kprobes.c               | 159 +++++++++++++++++++++++++++--------------
 2 files changed, 112 insertions(+), 54 deletions(-)

-- 
1.8.1.5

[PATCH v3 1/4] kprobes: delay blacklist symbol lookup until we actually need it

[Oskar Andero]

From: Toby Collett <toby.collett@sonymobile.com>

The symbol lookup can take a long time and kprobes is
initialised very early in boot, so delay symbol lookup
until the blacklist is first used.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David S. Miller <davem@davemloft.net>
Reviewed-by: Radovan Lekanovic <radovan.lekanovic@sonymobile.com>
Signed-off-by: Toby Collett <toby.collett@sonymobile.com>
Signed-off-by: Oskar Andero <oskar.andero@sonymobile.com>
---
 kernel/kprobes.c | 100 ++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 62 insertions(+), 38 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index e35be53..c8c2281 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -68,6 +68,7 @@
 #endif
 
 static int kprobes_initialized;
+static bool kprobe_blacklist_initialized;
 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
 
@@ -102,6 +103,62 @@ static struct kprobe_blackpoint kprobe_blacklist[] = {
 	{NULL}    /* Terminator */
 };
 
+/* it can take some time ( > 100ms ) to initialise the
+ * blacklist so we delay this until we actually need it
+ */
+static void init_kprobe_blacklist(void)
+{
+	int i;
+	unsigned long offset = 0, size = 0;
+	char *modname, namebuf[128];
+	const char *symbol_name;
+	void *addr;
+	struct kprobe_blackpoint *kb;
+
+	mutex_lock(&kprobe_mutex);
+	if (kprobe_blacklist_initialized)
+		goto out;
+
+	/*
+	 * Lookup and populate the kprobe_blacklist.
+	 *
+	 * Unlike the kretprobe blacklist, we'll need to determine
+	 * the range of addresses that belong to the said functions,
+	 * since a kprobe need not necessarily be at the beginning
+	 * of a function.
+	 */
+	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
+		kprobe_lookup_name(kb->name, addr);
+		if (!addr)
+			continue;
+
+		kb->start_addr = (unsigned long)addr;
+		symbol_name = kallsyms_lookup(kb->start_addr,
+				&size, &offset, &modname, namebuf);
+		if (!symbol_name)
+			kb->range = 0;
+		else
+			kb->range = size;
+	}
+
+	if (kretprobe_blacklist_size) {
+		/* lookup the function address from its name */
+		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
+			kprobe_lookup_name(kretprobe_blacklist[i].name,
+					   kretprobe_blacklist[i].addr);
+			if (!kretprobe_blacklist[i].addr)
+				printk("kretprobe: lookup failed: %s\n",
+				       kretprobe_blacklist[i].name);
+		}
+	}
+
+	smp_wmb();
+	kprobe_blacklist_initialized = true;
+
+out:
+	mutex_unlock(&kprobe_mutex);
+}
+
 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
 /*
  * kprobe->ainsn.insn points to the copy of the instruction to be
@@ -1331,6 +1388,9 @@ static int __kprobes in_kprobes_functions(unsigned long addr)
 	if (addr >= (unsigned long)__kprobes_text_start &&
 	    addr < (unsigned long)__kprobes_text_end)
 		return -EINVAL;
+
+	if (unlikely(!kprobe_blacklist_initialized))
+		init_kprobe_blacklist();
 	/*
 	 * If there exists a kprobe_blacklist, verify and
 	 * fail any probe registration in the prohibited area
@@ -1816,6 +1876,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
 	void *addr;
 
 	if (kretprobe_blacklist_size) {
+		if (unlikely(!kprobe_blacklist_initialized))
+			init_kprobe_blacklist();
 		addr = kprobe_addr(&rp->kp);
 		if (IS_ERR(addr))
 			return PTR_ERR(addr);
@@ -2065,11 +2127,6 @@ static struct notifier_block kprobe_module_nb = {
 static int __init init_kprobes(void)
 {
 	int i, err = 0;
-	unsigned long offset = 0, size = 0;
-	char *modname, namebuf[128];
-	const char *symbol_name;
-	void *addr;
-	struct kprobe_blackpoint *kb;
 
 	/* FIXME allocate the probe table, currently defined statically */
 	/* initialize all list heads */
@@ -2079,39 +2136,6 @@ static int __init init_kprobes(void)
 		raw_spin_lock_init(&(kretprobe_table_locks[i].lock));
 	}
 
-	/*
-	 * Lookup and populate the kprobe_blacklist.
-	 *
-	 * Unlike the kretprobe blacklist, we'll need to determine
-	 * the range of addresses that belong to the said functions,
-	 * since a kprobe need not necessarily be at the beginning
-	 * of a function.
-	 */
-	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
-		kprobe_lookup_name(kb->name, addr);
-		if (!addr)
-			continue;
-
-		kb->start_addr = (unsigned long)addr;
-		symbol_name = kallsyms_lookup(kb->start_addr,
-				&size, &offset, &modname, namebuf);
-		if (!symbol_name)
-			kb->range = 0;
-		else
-			kb->range = size;
-	}
-
-	if (kretprobe_blacklist_size) {
-		/* lookup the function address from its name */
-		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
-			kprobe_lookup_name(kretprobe_blacklist[i].name,
-					   kretprobe_blacklist[i].addr);
-			if (!kretprobe_blacklist[i].addr)
-				printk("kretprobe: lookup failed: %s\n",
-				       kretprobe_blacklist[i].name);
-		}
-	}
-
 #if defined(CONFIG_OPTPROBES)
 #if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
 	/* Init kprobe_optinsn_slots */
-- 
1.8.1.5

[PATCH v3 1/4] kprobes: delay blacklist symbol lookup until we actually need it

[Oskar Andero]

From: Toby Collett <toby.collett@sonymobile.com>

The symbol lookup can take a long time and kprobes is
initialised very early in boot, so delay symbol lookup
until the blacklist is first used.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David S. Miller <davem@davemloft.net>
Reviewed-by: Radovan Lekanovic <radovan.lekanovic@sonymobile.com>
Signed-off-by: Toby Collett <toby.collett@sonymobile.com>
Signed-off-by: Oskar Andero <oskar.andero@sonymobile.com>
---
 kernel/kprobes.c | 100 ++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 62 insertions(+), 38 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index e35be53..c8c2281 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -68,6 +68,7 @@
 #endif
 
 static int kprobes_initialized;
+static bool kprobe_blacklist_initialized;
 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
 
@@ -102,6 +103,62 @@ static struct kprobe_blackpoint kprobe_blacklist[] = {
 	{NULL}    /* Terminator */
 };
 
+/* it can take some time ( > 100ms ) to initialise the
+ * blacklist so we delay this until we actually need it
+ */
+static void init_kprobe_blacklist(void)
+{
+	int i;
+	unsigned long offset = 0, size = 0;
+	char *modname, namebuf[128];
+	const char *symbol_name;
+	void *addr;
+	struct kprobe_blackpoint *kb;
+
+	mutex_lock(&kprobe_mutex);
+	if (kprobe_blacklist_initialized)
+		goto out;
+
+	/*
+	 * Lookup and populate the kprobe_blacklist.
+	 *
+	 * Unlike the kretprobe blacklist, we'll need to determine
+	 * the range of addresses that belong to the said functions,
+	 * since a kprobe need not necessarily be at the beginning
+	 * of a function.
+	 */
+	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
+		kprobe_lookup_name(kb->name, addr);
+		if (!addr)
+			continue;
+
+		kb->start_addr = (unsigned long)addr;
+		symbol_name = kallsyms_lookup(kb->start_addr,
+				&size, &offset, &modname, namebuf);
+		if (!symbol_name)
+			kb->range = 0;
+		else
+			kb->range = size;
+	}
+
+	if (kretprobe_blacklist_size) {
+		/* lookup the function address from its name */
+		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
+			kprobe_lookup_name(kretprobe_blacklist[i].name,
+					   kretprobe_blacklist[i].addr);
+			if (!kretprobe_blacklist[i].addr)
+				printk("kretprobe: lookup failed: %s\n",
+				       kretprobe_blacklist[i].name);
+		}
+	}
+
+	smp_wmb();
+	kprobe_blacklist_initialized = true;
+
+out:
+	mutex_unlock(&kprobe_mutex);
+}
+
 #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
 /*
  * kprobe->ainsn.insn points to the copy of the instruction to be
@@ -1331,6 +1388,9 @@ static int __kprobes in_kprobes_functions(unsigned long addr)
 	if (addr >= (unsigned long)__kprobes_text_start &&
 	    addr < (unsigned long)__kprobes_text_end)
 		return -EINVAL;
+
+	if (unlikely(!kprobe_blacklist_initialized))
+		init_kprobe_blacklist();
 	/*
 	 * If there exists a kprobe_blacklist, verify and
 	 * fail any probe registration in the prohibited area
@@ -1816,6 +1876,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
 	void *addr;
 
 	if (kretprobe_blacklist_size) {
+		if (unlikely(!kprobe_blacklist_initialized))
+			init_kprobe_blacklist();
 		addr = kprobe_addr(&rp->kp);
 		if (IS_ERR(addr))
 			return PTR_ERR(addr);
@@ -2065,11 +2127,6 @@ static struct notifier_block kprobe_module_nb = {
 static int __init init_kprobes(void)
 {
 	int i, err = 0;
-	unsigned long offset = 0, size = 0;
-	char *modname, namebuf[128];
-	const char *symbol_name;
-	void *addr;
-	struct kprobe_blackpoint *kb;
 
 	/* FIXME allocate the probe table, currently defined statically */
 	/* initialize all list heads */
@@ -2079,39 +2136,6 @@ static int __init init_kprobes(void)
 		raw_spin_lock_init(&(kretprobe_table_locks[i].lock));
 	}
 
-	/*
-	 * Lookup and populate the kprobe_blacklist.
-	 *
-	 * Unlike the kretprobe blacklist, we'll need to determine
-	 * the range of addresses that belong to the said functions,
-	 * since a kprobe need not necessarily be at the beginning
-	 * of a function.
-	 */
-	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
-		kprobe_lookup_name(kb->name, addr);
-		if (!addr)
-			continue;
-
-		kb->start_addr = (unsigned long)addr;
-		symbol_name = kallsyms_lookup(kb->start_addr,
-				&size, &offset, &modname, namebuf);
-		if (!symbol_name)
-			kb->range = 0;
-		else
-			kb->range = size;
-	}
-
-	if (kretprobe_blacklist_size) {
-		/* lookup the function address from its name */
-		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
-			kprobe_lookup_name(kretprobe_blacklist[i].name,
-					   kretprobe_blacklist[i].addr);
-			if (!kretprobe_blacklist[i].addr)
-				printk("kretprobe: lookup failed: %s\n",
-				       kretprobe_blacklist[i].name);
-		}
-	}
-
 #if defined(CONFIG_OPTPROBES)
 #if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
 	/* Init kprobe_optinsn_slots */
-- 
1.8.1.5

[PATCH v3 2/4] kprobes: split blacklist into common and arch

[Oskar Andero]

Some blackpoints are only valid for specific architectures. To let each
architecture specify its own blackpoints the list has been split in two
lists: common and arch. The common list is kept in kernel/kprobes.c and
the arch list is kept in the arch/ directory.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Oskar Andero <oskar.andero@sonymobile.com>
---
 kernel/kprobes.c | 88 +++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 59 insertions(+), 29 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index c8c2281..2458ae1 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -68,7 +68,6 @@
 #endif
 
 static int kprobes_initialized;
-static bool kprobe_blacklist_initialized;
 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
 
@@ -94,31 +93,64 @@ static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
  *
  * For such cases, we now have a blacklist
  */
-static struct kprobe_blackpoint kprobe_blacklist[] = {
-	{"preempt_schedule",},
-	{"native_get_debugreg",},
-	{"irq_entries_start",},
-	{"common_interrupt",},
-	{"mcount",},	/* mcount can be called from everywhere */
-	{NULL}    /* Terminator */
+static const char * const common_kprobes_blacksyms[] = {
+	"preempt_schedule",
+	"native_get_debugreg",
+	"irq_entries_start",
+	"common_interrupt",
+	"mcount",       /* mcount can be called from everywhere */
 };
+static const size_t common_kprobes_blacksyms_size =
+			ARRAY_SIZE(common_kprobes_blacksyms);
+
+/*
+ * These weak symbols can be overridden from the arch/ directory for
+ * architecure specific blackpoints.
+ */
+const char * const __weak arch_kprobes_blacksyms[] = {};
+const size_t __weak arch_kprobes_blacksyms_size;
+
+static struct kprobe_blackpoint *kprobe_blacklist;
+static size_t kprobe_blacklist_size;
+
+static void init_kprobe_blacklist_entry(struct kprobe_blackpoint *kb,
+					const char * const name)
+{
+	const char *symbol_name;
+	char *modname, namebuf[128];
+	void *addr;
+	unsigned long offset = 0, size = 0;
+
+	kb->name = name;
+	kprobe_lookup_name(kb->name, addr);
+	if (!addr)
+		return;
+
+	kb->start_addr = (unsigned long)addr;
+	symbol_name = kallsyms_lookup(kb->start_addr,
+			&size, &offset, &modname, namebuf);
+	if (!symbol_name)
+		kb->range = 0;
+	else
+		kb->range = size;
+}
 
 /* it can take some time ( > 100ms ) to initialise the
  * blacklist so we delay this until we actually need it
  */
 static void init_kprobe_blacklist(void)
 {
-	int i;
-	unsigned long offset = 0, size = 0;
-	char *modname, namebuf[128];
-	const char *symbol_name;
-	void *addr;
+	int i, j = 0;
 	struct kprobe_blackpoint *kb;
 
 	mutex_lock(&kprobe_mutex);
-	if (kprobe_blacklist_initialized)
+	if (kprobe_blacklist)
 		goto out;
 
+	kprobe_blacklist_size = common_kprobes_blacksyms_size +
+				arch_kprobes_blacksyms_size;
+	kb = kzalloc(sizeof(*kb) * kprobe_blacklist_size, GFP_KERNEL);
+
 	/*
 	 * Lookup and populate the kprobe_blacklist.
 	 *
@@ -127,18 +159,14 @@ static void init_kprobe_blacklist(void)
 	 * since a kprobe need not necessarily be at the beginning
 	 * of a function.
 	 */
-	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
-		kprobe_lookup_name(kb->name, addr);
-		if (!addr)
-			continue;
+	for (i = 0; i < common_kprobes_blacksyms_size; i++, j++) {
+		init_kprobe_blacklist_entry(&kb[j],
+					    common_kprobes_blacksyms[i]);
+	}
 
-		kb->start_addr = (unsigned long)addr;
-		symbol_name = kallsyms_lookup(kb->start_addr,
-				&size, &offset, &modname, namebuf);
-		if (!symbol_name)
-			kb->range = 0;
-		else
-			kb->range = size;
+	for (i = 0; i < arch_kprobes_blacksyms_size; i++, j++) {
+		init_kprobe_blacklist_entry(&kb[j],
+					    arch_kprobes_blacksyms[i]);
 	}
 
 	if (kretprobe_blacklist_size) {
@@ -153,7 +181,7 @@ static void init_kprobe_blacklist(void)
 	}
 
 	smp_wmb();
-	kprobe_blacklist_initialized = true;
+	kprobe_blacklist = kb;
 
 out:
 	mutex_unlock(&kprobe_mutex);
@@ -1384,18 +1412,20 @@ out:
 static int __kprobes in_kprobes_functions(unsigned long addr)
 {
 	struct kprobe_blackpoint *kb;
+	int i;
 
 	if (addr >= (unsigned long)__kprobes_text_start &&
 	    addr < (unsigned long)__kprobes_text_end)
 		return -EINVAL;
 
-	if (unlikely(!kprobe_blacklist_initialized))
+	if (unlikely(!kprobe_blacklist))
 		init_kprobe_blacklist();
 	/*
 	 * If there exists a kprobe_blacklist, verify and
 	 * fail any probe registration in the prohibited area
 	 */
-	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
+	for (i = 0; i < kprobe_blacklist_size; i++) {
+		kb = &kprobe_blacklist[i];
 		if (kb->start_addr) {
 			if (addr >= kb->start_addr &&
 			    addr < (kb->start_addr + kb->range))
@@ -1876,7 +1906,7 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
 	void *addr;
 
 	if (kretprobe_blacklist_size) {
-		if (unlikely(!kprobe_blacklist_initialized))
+		if (unlikely(!kprobe_blacklist))
 			init_kprobe_blacklist();
 		addr = kprobe_addr(&rp->kp);
 		if (IS_ERR(addr))
-- 
1.8.1.5

[PATCH v3 2/4] kprobes: split blacklist into common and arch

[Oskar Andero]

Some blackpoints are only valid for specific architectures. To let each
architecture specify its own blackpoints the list has been split in two
lists: common and arch. The common list is kept in kernel/kprobes.c and
the arch list is kept in the arch/ directory.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Oskar Andero <oskar.andero@sonymobile.com>
---
 kernel/kprobes.c | 88 +++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 59 insertions(+), 29 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index c8c2281..2458ae1 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -68,7 +68,6 @@
 #endif
 
 static int kprobes_initialized;
-static bool kprobe_blacklist_initialized;
 static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
 static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
 
@@ -94,31 +93,64 @@ static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
  *
  * For such cases, we now have a blacklist
  */
-static struct kprobe_blackpoint kprobe_blacklist[] = {
-	{"preempt_schedule",},
-	{"native_get_debugreg",},
-	{"irq_entries_start",},
-	{"common_interrupt",},
-	{"mcount",},	/* mcount can be called from everywhere */
-	{NULL}    /* Terminator */
+static const char * const common_kprobes_blacksyms[] = {
+	"preempt_schedule",
+	"native_get_debugreg",
+	"irq_entries_start",
+	"common_interrupt",
+	"mcount",       /* mcount can be called from everywhere */
 };
+static const size_t common_kprobes_blacksyms_size =
+			ARRAY_SIZE(common_kprobes_blacksyms);
+
+/*
+ * These weak symbols can be overridden from the arch/ directory for
+ * architecure specific blackpoints.
+ */
+const char * const __weak arch_kprobes_blacksyms[] = {};
+const size_t __weak arch_kprobes_blacksyms_size;
+
+static struct kprobe_blackpoint *kprobe_blacklist;
+static size_t kprobe_blacklist_size;
+
+static void init_kprobe_blacklist_entry(struct kprobe_blackpoint *kb,
+					const char * const name)
+{
+	const char *symbol_name;
+	char *modname, namebuf[128];
+	void *addr;
+	unsigned long offset = 0, size = 0;
+
+	kb->name = name;
+	kprobe_lookup_name(kb->name, addr);
+	if (!addr)
+		return;
+
+	kb->start_addr = (unsigned long)addr;
+	symbol_name = kallsyms_lookup(kb->start_addr,
+			&size, &offset, &modname, namebuf);
+	if (!symbol_name)
+		kb->range = 0;
+	else
+		kb->range = size;
+}
 
 /* it can take some time ( > 100ms ) to initialise the
  * blacklist so we delay this until we actually need it
  */
 static void init_kprobe_blacklist(void)
 {
-	int i;
-	unsigned long offset = 0, size = 0;
-	char *modname, namebuf[128];
-	const char *symbol_name;
-	void *addr;
+	int i, j = 0;
 	struct kprobe_blackpoint *kb;
 
 	mutex_lock(&kprobe_mutex);
-	if (kprobe_blacklist_initialized)
+	if (kprobe_blacklist)
 		goto out;
 
+	kprobe_blacklist_size = common_kprobes_blacksyms_size +
+				arch_kprobes_blacksyms_size;
+	kb = kzalloc(sizeof(*kb) * kprobe_blacklist_size, GFP_KERNEL);
+
 	/*
 	 * Lookup and populate the kprobe_blacklist.
 	 *
@@ -127,18 +159,14 @@ static void init_kprobe_blacklist(void)
 	 * since a kprobe need not necessarily be at the beginning
 	 * of a function.
 	 */
-	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
-		kprobe_lookup_name(kb->name, addr);
-		if (!addr)
-			continue;
+	for (i = 0; i < common_kprobes_blacksyms_size; i++, j++) {
+		init_kprobe_blacklist_entry(&kb[j],
+					    common_kprobes_blacksyms[i]);
+	}
 
-		kb->start_addr = (unsigned long)addr;
-		symbol_name = kallsyms_lookup(kb->start_addr,
-				&size, &offset, &modname, namebuf);
-		if (!symbol_name)
-			kb->range = 0;
-		else
-			kb->range = size;
+	for (i = 0; i < arch_kprobes_blacksyms_size; i++, j++) {
+		init_kprobe_blacklist_entry(&kb[j],
+					    arch_kprobes_blacksyms[i]);
 	}
 
 	if (kretprobe_blacklist_size) {
@@ -153,7 +181,7 @@ static void init_kprobe_blacklist(void)
 	}
 
 	smp_wmb();
-	kprobe_blacklist_initialized = true;
+	kprobe_blacklist = kb;
 
 out:
 	mutex_unlock(&kprobe_mutex);
@@ -1384,18 +1412,20 @@ out:
 static int __kprobes in_kprobes_functions(unsigned long addr)
 {
 	struct kprobe_blackpoint *kb;
+	int i;
 
 	if (addr >= (unsigned long)__kprobes_text_start &&
 	    addr < (unsigned long)__kprobes_text_end)
 		return -EINVAL;
 
-	if (unlikely(!kprobe_blacklist_initialized))
+	if (unlikely(!kprobe_blacklist))
 		init_kprobe_blacklist();
 	/*
 	 * If there exists a kprobe_blacklist, verify and
 	 * fail any probe registration in the prohibited area
 	 */
-	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
+	for (i = 0; i < kprobe_blacklist_size; i++) {
+		kb = &kprobe_blacklist[i];
 		if (kb->start_addr) {
 			if (addr >= kb->start_addr &&
 			    addr < (kb->start_addr + kb->range))
@@ -1876,7 +1906,7 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
 	void *addr;
 
 	if (kretprobe_blacklist_size) {
-		if (unlikely(!kprobe_blacklist_initialized))
+		if (unlikely(!kprobe_blacklist))
 			init_kprobe_blacklist();
 		addr = kprobe_addr(&rp->kp);
 		if (IS_ERR(addr))
-- 
1.8.1.5

[PATCH v3 3/4] kprobes: move x86-specific blacklist symbols to arch directory

[Oskar Andero]

From: Björn Davidsson <bjorn.davidsson@sonymobile.com>

The common kprobes blacklist contains x86-specific symbols.
Looking for these in kallsyms takes unnecessary time during startup
on non-X86 platform. The symbols where moved to
arch/x86/kernel/kprobes/core.c.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: linux-arch@vger.kernel.org
Reviewed-by: Radovan Lekanovic <radovan.lekanovic@sonymobile.com>
Signed-off-by: Björn Davidsson <bjorn.davidsson@sonymobile.com>
Signed-off-by: Oskar Andero <oskar.andero@sonymobile.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
 arch/x86/kernel/kprobes/core.c | 7 +++++++
 kernel/kprobes.c               | 3 ---
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 7bfe318..41ce6c1 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -65,6 +65,13 @@ void jprobe_return_end(void);
 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 
+const char * const arch_kprobes_blacksyms[] = {
+	"native_get_debugreg",
+	"irq_entries_start",
+	"common_interrupt",
+};
+const size_t arch_kprobes_blacksyms_size = ARRAY_SIZE(arch_kprobes_blacksyms);
+
 #define stack_addr(regs) ((unsigned long *)kernel_stack_pointer(regs))
 
 #define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 2458ae1..b289384 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -95,9 +95,6 @@ static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
  */
 static const char * const common_kprobes_blacksyms[] = {
 	"preempt_schedule",
-	"native_get_debugreg",
-	"irq_entries_start",
-	"common_interrupt",
 	"mcount",       /* mcount can be called from everywhere */
 };
 static const size_t common_kprobes_blacksyms_size =
-- 
1.8.1.5

[PATCH v3 3/4] kprobes: move x86-specific blacklist symbols to arch directory

[Oskar Andero]

From: Björn Davidsson <bjorn.davidsson@sonymobile.com>

The common kprobes blacklist contains x86-specific symbols.
Looking for these in kallsyms takes unnecessary time during startup
on non-X86 platform. The symbols where moved to
arch/x86/kernel/kprobes/core.c.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: linux-arch@vger.kernel.org
Reviewed-by: Radovan Lekanovic <radovan.lekanovic@sonymobile.com>
Signed-off-by: Björn Davidsson <bjorn.davidsson@sonymobile.com>
Signed-off-by: Oskar Andero <oskar.andero@sonymobile.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
 arch/x86/kernel/kprobes/core.c | 7 +++++++
 kernel/kprobes.c               | 3 ---
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 7bfe318..41ce6c1 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -65,6 +65,13 @@ void jprobe_return_end(void);
 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 
+const char * const arch_kprobes_blacksyms[] = {
+	"native_get_debugreg",
+	"irq_entries_start",
+	"common_interrupt",
+};
+const size_t arch_kprobes_blacksyms_size = ARRAY_SIZE(arch_kprobes_blacksyms);
+
 #define stack_addr(regs) ((unsigned long *)kernel_stack_pointer(regs))
 
 #define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 2458ae1..b289384 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -95,9 +95,6 @@ static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
  */
 static const char * const common_kprobes_blacksyms[] = {
 	"preempt_schedule",
-	"native_get_debugreg",
-	"irq_entries_start",
-	"common_interrupt",
 	"mcount",       /* mcount can be called from everywhere */
 };
 static const size_t common_kprobes_blacksyms_size =
-- 
1.8.1.5

[PATCH v3 4/4] kprobes: replace printk with pr_-functions

[Oskar Andero]

Instead of using printk use pr_info/pr_err/pr_warn. This was
detected by the checkpatch.pl script.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Oskar Andero <oskar.andero@sonymobile.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
 kernel/kprobes.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index b289384..08facfc 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -172,7 +172,7 @@ static void init_kprobe_blacklist(void)
 			kprobe_lookup_name(kretprobe_blacklist[i].name,
 					   kretprobe_blacklist[i].addr);
 			if (!kretprobe_blacklist[i].addr)
-				printk("kretprobe: lookup failed: %s\n",
+				pr_err("kretprobe: lookup failed: %s\n",
 				       kretprobe_blacklist[i].name);
 		}
 	}
@@ -787,7 +787,7 @@ static void reuse_unused_kprobe(struct kprobe *ap)
 	 */
 	op = container_of(ap, struct optimized_kprobe, kp);
 	if (unlikely(list_empty(&op->list)))
-		printk(KERN_WARNING "Warning: found a stray unused "
+		pr_warn("Warning: found a stray unused "
 			"aggrprobe@%p\n", ap->addr);
 	/* Enable the probe again */
 	ap->flags &= ~KPROBE_FLAG_DISABLED;
@@ -894,7 +894,7 @@ static void __kprobes optimize_all_kprobes(void)
 			if (!kprobe_disabled(p))
 				optimize_kprobe(p);
 	}
-	printk(KERN_INFO "Kprobes globally optimized\n");
+	pr_info("Kprobes globally optimized\n");
 }
 
 /* This should be called with kprobe_mutex locked */
@@ -918,7 +918,7 @@ static void __kprobes unoptimize_all_kprobes(void)
 	}
 	/* Wait for unoptimizing completion */
 	wait_for_kprobe_optimizer();
-	printk(KERN_INFO "Kprobes globally unoptimized\n");
+	pr_info("Kprobes globally unoptimized\n");
 }
 
 int sysctl_kprobes_optimization;
@@ -989,7 +989,7 @@ static void __kprobes __disarm_kprobe(struct kprobe *p, bool reopt)
 /* There should be no unused kprobes can be reused without optimization */
 static void reuse_unused_kprobe(struct kprobe *ap)
 {
-	printk(KERN_ERR "Error: There should be no unused kprobe here.\n");
+	pr_err("Error: There should be no unused kprobe here.\n");
 	BUG_ON(kprobe_unused(ap));
 }
 
@@ -2103,8 +2103,8 @@ EXPORT_SYMBOL_GPL(enable_kprobe);
 
 void __kprobes dump_kprobe(struct kprobe *kp)
 {
-	printk(KERN_WARNING "Dumping kprobe:\n");
-	printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n",
+	pr_warn("Dumping kprobe:\n");
+	pr_warn("Name: %s\nAddress: %p\nOffset: %x\n",
 	       kp->symbol_name, kp->addr, kp->offset);
 }
 
@@ -2300,7 +2300,7 @@ static void __kprobes arm_all_kprobes(void)
 	}
 
 	kprobes_all_disarmed = false;
-	printk(KERN_INFO "Kprobes globally enabled\n");
+	pr_info("Kprobes globally enabled\n");
 
 already_enabled:
 	mutex_unlock(&kprobe_mutex);
@@ -2322,7 +2322,7 @@ static void __kprobes disarm_all_kprobes(void)
 	}
 
 	kprobes_all_disarmed = true;
-	printk(KERN_INFO "Kprobes globally disabled\n");
+	pr_info("Kprobes globally disabled\n");
 
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
 		head = &kprobe_table[i];
-- 
1.8.1.5

Re: [PATCH v3 1/4] kprobes: delay blacklist symbol lookup until we actually need it

[Masami Hiramatsu]

(2013/04/05 22:26), Oskar Andero wrote:
> From: Toby Collett <toby.collett@sonymobile.com>
> 
> The symbol lookup can take a long time and kprobes is
> initialised very early in boot, so delay symbol lookup
> until the blacklist is first used.

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Thanks!

> 
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: David S. Miller <davem@davemloft.net>
> Reviewed-by: Radovan Lekanovic <radovan.lekanovic@sonymobile.com>
> Signed-off-by: Toby Collett <toby.collett@sonymobile.com>
> Signed-off-by: Oskar Andero <oskar.andero@sonymobile.com>
> ---
>  kernel/kprobes.c | 100 ++++++++++++++++++++++++++++++++++---------------------
>  1 file changed, 62 insertions(+), 38 deletions(-)
> 
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index e35be53..c8c2281 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -68,6 +68,7 @@
>  #endif
>  
>  static int kprobes_initialized;
> +static bool kprobe_blacklist_initialized;
>  static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
>  static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
>  
> @@ -102,6 +103,62 @@ static struct kprobe_blackpoint kprobe_blacklist[] = {
>  	{NULL}    /* Terminator */
>  };
>  
> +/* it can take some time ( > 100ms ) to initialise the
> + * blacklist so we delay this until we actually need it
> + */
> +static void init_kprobe_blacklist(void)
> +{
> +	int i;
> +	unsigned long offset = 0, size = 0;
> +	char *modname, namebuf[128];
> +	const char *symbol_name;
> +	void *addr;
> +	struct kprobe_blackpoint *kb;
> +
> +	mutex_lock(&kprobe_mutex);
> +	if (kprobe_blacklist_initialized)
> +		goto out;
> +
> +	/*
> +	 * Lookup and populate the kprobe_blacklist.
> +	 *
> +	 * Unlike the kretprobe blacklist, we'll need to determine
> +	 * the range of addresses that belong to the said functions,
> +	 * since a kprobe need not necessarily be at the beginning
> +	 * of a function.
> +	 */
> +	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
> +		kprobe_lookup_name(kb->name, addr);
> +		if (!addr)
> +			continue;
> +
> +		kb->start_addr = (unsigned long)addr;
> +		symbol_name = kallsyms_lookup(kb->start_addr,
> +				&size, &offset, &modname, namebuf);
> +		if (!symbol_name)
> +			kb->range = 0;
> +		else
> +			kb->range = size;
> +	}
> +
> +	if (kretprobe_blacklist_size) {
> +		/* lookup the function address from its name */
> +		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
> +			kprobe_lookup_name(kretprobe_blacklist[i].name,
> +					   kretprobe_blacklist[i].addr);
> +			if (!kretprobe_blacklist[i].addr)
> +				printk("kretprobe: lookup failed: %s\n",
> +				       kretprobe_blacklist[i].name);
> +		}
> +	}
> +
> +	smp_wmb();
> +	kprobe_blacklist_initialized = true;
> +
> +out:
> +	mutex_unlock(&kprobe_mutex);
> +}
> +
>  #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
>  /*
>   * kprobe->ainsn.insn points to the copy of the instruction to be
> @@ -1331,6 +1388,9 @@ static int __kprobes in_kprobes_functions(unsigned long addr)
>  	if (addr >= (unsigned long)__kprobes_text_start &&
>  	    addr < (unsigned long)__kprobes_text_end)
>  		return -EINVAL;
> +
> +	if (unlikely(!kprobe_blacklist_initialized))
> +		init_kprobe_blacklist();
>  	/*
>  	 * If there exists a kprobe_blacklist, verify and
>  	 * fail any probe registration in the prohibited area
> @@ -1816,6 +1876,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
>  	void *addr;
>  
>  	if (kretprobe_blacklist_size) {
> +		if (unlikely(!kprobe_blacklist_initialized))
> +			init_kprobe_blacklist();
>  		addr = kprobe_addr(&rp->kp);
>  		if (IS_ERR(addr))
>  			return PTR_ERR(addr);
> @@ -2065,11 +2127,6 @@ static struct notifier_block kprobe_module_nb = {
>  static int __init init_kprobes(void)
>  {
>  	int i, err = 0;
> -	unsigned long offset = 0, size = 0;
> -	char *modname, namebuf[128];
> -	const char *symbol_name;
> -	void *addr;
> -	struct kprobe_blackpoint *kb;
>  
>  	/* FIXME allocate the probe table, currently defined statically */
>  	/* initialize all list heads */
> @@ -2079,39 +2136,6 @@ static int __init init_kprobes(void)
>  		raw_spin_lock_init(&(kretprobe_table_locks[i].lock));
>  	}
>  
> -	/*
> -	 * Lookup and populate the kprobe_blacklist.
> -	 *
> -	 * Unlike the kretprobe blacklist, we'll need to determine
> -	 * the range of addresses that belong to the said functions,
> -	 * since a kprobe need not necessarily be at the beginning
> -	 * of a function.
> -	 */
> -	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
> -		kprobe_lookup_name(kb->name, addr);
> -		if (!addr)
> -			continue;
> -
> -		kb->start_addr = (unsigned long)addr;
> -		symbol_name = kallsyms_lookup(kb->start_addr,
> -				&size, &offset, &modname, namebuf);
> -		if (!symbol_name)
> -			kb->range = 0;
> -		else
> -			kb->range = size;
> -	}
> -
> -	if (kretprobe_blacklist_size) {
> -		/* lookup the function address from its name */
> -		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
> -			kprobe_lookup_name(kretprobe_blacklist[i].name,
> -					   kretprobe_blacklist[i].addr);
> -			if (!kretprobe_blacklist[i].addr)
> -				printk("kretprobe: lookup failed: %s\n",
> -				       kretprobe_blacklist[i].name);
> -		}
> -	}
> -
>  #if defined(CONFIG_OPTPROBES)
>  #if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
>  	/* Init kprobe_optinsn_slots */
> 


-- 
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com

Re: [PATCH v3 1/4] kprobes: delay blacklist symbol lookup until we actually need it

[Masami Hiramatsu]

(2013/04/05 22:26), Oskar Andero wrote:
> From: Toby Collett <toby.collett@sonymobile.com>
> 
> The symbol lookup can take a long time and kprobes is
> initialised very early in boot, so delay symbol lookup
> until the blacklist is first used.

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Thanks!

> 
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: David S. Miller <davem@davemloft.net>
> Reviewed-by: Radovan Lekanovic <radovan.lekanovic@sonymobile.com>
> Signed-off-by: Toby Collett <toby.collett@sonymobile.com>
> Signed-off-by: Oskar Andero <oskar.andero@sonymobile.com>
> ---
>  kernel/kprobes.c | 100 ++++++++++++++++++++++++++++++++++---------------------
>  1 file changed, 62 insertions(+), 38 deletions(-)
> 
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index e35be53..c8c2281 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -68,6 +68,7 @@
>  #endif
>  
>  static int kprobes_initialized;
> +static bool kprobe_blacklist_initialized;
>  static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
>  static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
>  
> @@ -102,6 +103,62 @@ static struct kprobe_blackpoint kprobe_blacklist[] = {
>  	{NULL}    /* Terminator */
>  };
>  
> +/* it can take some time ( > 100ms ) to initialise the
> + * blacklist so we delay this until we actually need it
> + */
> +static void init_kprobe_blacklist(void)
> +{
> +	int i;
> +	unsigned long offset = 0, size = 0;
> +	char *modname, namebuf[128];
> +	const char *symbol_name;
> +	void *addr;
> +	struct kprobe_blackpoint *kb;
> +
> +	mutex_lock(&kprobe_mutex);
> +	if (kprobe_blacklist_initialized)
> +		goto out;
> +
> +	/*
> +	 * Lookup and populate the kprobe_blacklist.
> +	 *
> +	 * Unlike the kretprobe blacklist, we'll need to determine
> +	 * the range of addresses that belong to the said functions,
> +	 * since a kprobe need not necessarily be at the beginning
> +	 * of a function.
> +	 */
> +	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
> +		kprobe_lookup_name(kb->name, addr);
> +		if (!addr)
> +			continue;
> +
> +		kb->start_addr = (unsigned long)addr;
> +		symbol_name = kallsyms_lookup(kb->start_addr,
> +				&size, &offset, &modname, namebuf);
> +		if (!symbol_name)
> +			kb->range = 0;
> +		else
> +			kb->range = size;
> +	}
> +
> +	if (kretprobe_blacklist_size) {
> +		/* lookup the function address from its name */
> +		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
> +			kprobe_lookup_name(kretprobe_blacklist[i].name,
> +					   kretprobe_blacklist[i].addr);
> +			if (!kretprobe_blacklist[i].addr)
> +				printk("kretprobe: lookup failed: %s\n",
> +				       kretprobe_blacklist[i].name);
> +		}
> +	}
> +
> +	smp_wmb();
> +	kprobe_blacklist_initialized = true;
> +
> +out:
> +	mutex_unlock(&kprobe_mutex);
> +}
> +
>  #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
>  /*
>   * kprobe->ainsn.insn points to the copy of the instruction to be
> @@ -1331,6 +1388,9 @@ static int __kprobes in_kprobes_functions(unsigned long addr)
>  	if (addr >= (unsigned long)__kprobes_text_start &&
>  	    addr < (unsigned long)__kprobes_text_end)
>  		return -EINVAL;
> +
> +	if (unlikely(!kprobe_blacklist_initialized))
> +		init_kprobe_blacklist();
>  	/*
>  	 * If there exists a kprobe_blacklist, verify and
>  	 * fail any probe registration in the prohibited area
> @@ -1816,6 +1876,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
>  	void *addr;
>  
>  	if (kretprobe_blacklist_size) {
> +		if (unlikely(!kprobe_blacklist_initialized))
> +			init_kprobe_blacklist();
>  		addr = kprobe_addr(&rp->kp);
>  		if (IS_ERR(addr))
>  			return PTR_ERR(addr);
> @@ -2065,11 +2127,6 @@ static struct notifier_block kprobe_module_nb = {
>  static int __init init_kprobes(void)
>  {
>  	int i, err = 0;
> -	unsigned long offset = 0, size = 0;
> -	char *modname, namebuf[128];
> -	const char *symbol_name;
> -	void *addr;
> -	struct kprobe_blackpoint *kb;
>  
>  	/* FIXME allocate the probe table, currently defined statically */
>  	/* initialize all list heads */
> @@ -2079,39 +2136,6 @@ static int __init init_kprobes(void)
>  		raw_spin_lock_init(&(kretprobe_table_locks[i].lock));
>  	}
>  
> -	/*
> -	 * Lookup and populate the kprobe_blacklist.
> -	 *
> -	 * Unlike the kretprobe blacklist, we'll need to determine
> -	 * the range of addresses that belong to the said functions,
> -	 * since a kprobe need not necessarily be at the beginning
> -	 * of a function.
> -	 */
> -	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
> -		kprobe_lookup_name(kb->name, addr);
> -		if (!addr)
> -			continue;
> -
> -		kb->start_addr = (unsigned long)addr;
> -		symbol_name = kallsyms_lookup(kb->start_addr,
> -				&size, &offset, &modname, namebuf);
> -		if (!symbol_name)
> -			kb->range = 0;
> -		else
> -			kb->range = size;
> -	}
> -
> -	if (kretprobe_blacklist_size) {
> -		/* lookup the function address from its name */
> -		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
> -			kprobe_lookup_name(kretprobe_blacklist[i].name,
> -					   kretprobe_blacklist[i].addr);
> -			if (!kretprobe_blacklist[i].addr)
> -				printk("kretprobe: lookup failed: %s\n",
> -				       kretprobe_blacklist[i].name);
> -		}
> -	}
> -
>  #if defined(CONFIG_OPTPROBES)
>  #if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
>  	/* Init kprobe_optinsn_slots */
> 


-- 
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com

Re: [PATCH v3 2/4] kprobes: split blacklist into common and arch

[Masami Hiramatsu]

(2013/04/05 22:26), Oskar Andero wrote:
> Some blackpoints are only valid for specific architectures. To let each
> architecture specify its own blackpoints the list has been split in two
> lists: common and arch. The common list is kept in kernel/kprobes.c and
> the arch list is kept in the arch/ directory.

Looks good for me:)

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Thank you!

> 
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: David S. Miller <davem@davemloft.net>
> Cc: linux-arch@vger.kernel.org
> Signed-off-by: Oskar Andero <oskar.andero@sonymobile.com>
> ---
>  kernel/kprobes.c | 88 +++++++++++++++++++++++++++++++++++++-------------------
>  1 file changed, 59 insertions(+), 29 deletions(-)
> 
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index c8c2281..2458ae1 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -68,7 +68,6 @@
>  #endif
>  
>  static int kprobes_initialized;
> -static bool kprobe_blacklist_initialized;
>  static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
>  static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
>  
> @@ -94,31 +93,64 @@ static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
>   *
>   * For such cases, we now have a blacklist
>   */
> -static struct kprobe_blackpoint kprobe_blacklist[] = {
> -	{"preempt_schedule",},
> -	{"native_get_debugreg",},
> -	{"irq_entries_start",},
> -	{"common_interrupt",},
> -	{"mcount",},	/* mcount can be called from everywhere */
> -	{NULL}    /* Terminator */
> +static const char * const common_kprobes_blacksyms[] = {
> +	"preempt_schedule",
> +	"native_get_debugreg",
> +	"irq_entries_start",
> +	"common_interrupt",
> +	"mcount",       /* mcount can be called from everywhere */
>  };
> +static const size_t common_kprobes_blacksyms_size =
> +			ARRAY_SIZE(common_kprobes_blacksyms);
> +
> +/*
> + * These weak symbols can be overridden from the arch/ directory for
> + * architecure specific blackpoints.
> + */
> +const char * const __weak arch_kprobes_blacksyms[] = {};
> +const size_t __weak arch_kprobes_blacksyms_size;
> +
> +static struct kprobe_blackpoint *kprobe_blacklist;
> +static size_t kprobe_blacklist_size;
> +
> +static void init_kprobe_blacklist_entry(struct kprobe_blackpoint *kb,
> +					const char * const name)
> +{
> +	const char *symbol_name;
> +	char *modname, namebuf[128];
> +	void *addr;
> +	unsigned long offset = 0, size = 0;
> +
> +	kb->name = name;
> +	kprobe_lookup_name(kb->name, addr);
> +	if (!addr)
> +		return;
> +
> +	kb->start_addr = (unsigned long)addr;
> +	symbol_name = kallsyms_lookup(kb->start_addr,
> +			&size, &offset, &modname, namebuf);
> +	if (!symbol_name)
> +		kb->range = 0;
> +	else
> +		kb->range = size;
> +}
>  
>  /* it can take some time ( > 100ms ) to initialise the
>   * blacklist so we delay this until we actually need it
>   */
>  static void init_kprobe_blacklist(void)
>  {
> -	int i;
> -	unsigned long offset = 0, size = 0;
> -	char *modname, namebuf[128];
> -	const char *symbol_name;
> -	void *addr;
> +	int i, j = 0;
>  	struct kprobe_blackpoint *kb;
>  
>  	mutex_lock(&kprobe_mutex);
> -	if (kprobe_blacklist_initialized)
> +	if (kprobe_blacklist)
>  		goto out;
>  
> +	kprobe_blacklist_size = common_kprobes_blacksyms_size +
> +				arch_kprobes_blacksyms_size;
> +	kb = kzalloc(sizeof(*kb) * kprobe_blacklist_size, GFP_KERNEL);
> +
>  	/*
>  	 * Lookup and populate the kprobe_blacklist.
>  	 *
> @@ -127,18 +159,14 @@ static void init_kprobe_blacklist(void)
>  	 * since a kprobe need not necessarily be at the beginning
>  	 * of a function.
>  	 */
> -	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
> -		kprobe_lookup_name(kb->name, addr);
> -		if (!addr)
> -			continue;
> +	for (i = 0; i < common_kprobes_blacksyms_size; i++, j++) {
> +		init_kprobe_blacklist_entry(&kb[j],
> +					    common_kprobes_blacksyms[i]);
> +	}
>  
> -		kb->start_addr = (unsigned long)addr;
> -		symbol_name = kallsyms_lookup(kb->start_addr,
> -				&size, &offset, &modname, namebuf);
> -		if (!symbol_name)
> -			kb->range = 0;
> -		else
> -			kb->range = size;
> +	for (i = 0; i < arch_kprobes_blacksyms_size; i++, j++) {
> +		init_kprobe_blacklist_entry(&kb[j],
> +					    arch_kprobes_blacksyms[i]);
>  	}
>  
>  	if (kretprobe_blacklist_size) {
> @@ -153,7 +181,7 @@ static void init_kprobe_blacklist(void)
>  	}
>  
>  	smp_wmb();
> -	kprobe_blacklist_initialized = true;
> +	kprobe_blacklist = kb;
>  
>  out:
>  	mutex_unlock(&kprobe_mutex);
> @@ -1384,18 +1412,20 @@ out:
>  static int __kprobes in_kprobes_functions(unsigned long addr)
>  {
>  	struct kprobe_blackpoint *kb;
> +	int i;
>  
>  	if (addr >= (unsigned long)__kprobes_text_start &&
>  	    addr < (unsigned long)__kprobes_text_end)
>  		return -EINVAL;
>  
> -	if (unlikely(!kprobe_blacklist_initialized))
> +	if (unlikely(!kprobe_blacklist))
>  		init_kprobe_blacklist();
>  	/*
>  	 * If there exists a kprobe_blacklist, verify and
>  	 * fail any probe registration in the prohibited area
>  	 */
> -	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
> +	for (i = 0; i < kprobe_blacklist_size; i++) {
> +		kb = &kprobe_blacklist[i];
>  		if (kb->start_addr) {
>  			if (addr >= kb->start_addr &&
>  			    addr < (kb->start_addr + kb->range))
> @@ -1876,7 +1906,7 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
>  	void *addr;
>  
>  	if (kretprobe_blacklist_size) {
> -		if (unlikely(!kprobe_blacklist_initialized))
> +		if (unlikely(!kprobe_blacklist))
>  			init_kprobe_blacklist();
>  		addr = kprobe_addr(&rp->kp);
>  		if (IS_ERR(addr))
> 


-- 
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com