Re: [PATCH 1/4] kprobes: delay blacklist symbol lookup until we actually need it
On 08:44 Thu 04 Apr , Masami Hiramatsu wrote:
> (2013/04/03 17:28), oskar.and...@sonymobile.com wrote:
> >
> > +/* 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;
> > +
> > + /*
> > +* 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,
> > + , , , 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);
> > + }
> > + }
> > + kprobe_blacklist_initialized = 1;
> > +}
> > +
> > #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
> > /*
> > * kprobe->ainsn.insn points to the copy of the instruction to be
> > @@ -1331,6 +1379,9 @@ 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 (!kprobe_blacklist_initialized)
> > + init_kprobe_blacklist();
> > /*
> > * If there exists a kprobe_blacklist, verify and
> > * fail any probe registration in the prohibited area
> > @@ -1816,6 +1867,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
> > void *addr;
> >
> > if (kretprobe_blacklist_size) {
> > + if (!kprobe_blacklist_initialized)
> > + init_kprobe_blacklist();
>
> Joonsoo reminds me that these calling points are not protected by
> kprobe_mutex,
> thus we have to do something for avoiding concurrent initialization.
>
> Perhaps, the easiest way is to protect init_kprobe_blacklist() by kprobe_mutex
> and check kprobe_blacklist_initialized again in the top of that.
Yes, you are right. I had a second look at Joonsoo's patch and I will
add a similar mutex for v2.
-Oskar
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Re: [PATCH 1/4] kprobes: delay blacklist symbol lookup until we actually need it
(2013/04/03 17:28), oskar.and...@sonymobile.com wrote:
>
> +/* 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;
> +
> + /*
> + * 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,
> + , , , 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);
> + }
> + }
> + kprobe_blacklist_initialized = 1;
> +}
> +
> #ifdef __ARCH_WANT_KPROBES_INSN_SLOT
> /*
> * kprobe->ainsn.insn points to the copy of the instruction to be
> @@ -1331,6 +1379,9 @@ 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 (!kprobe_blacklist_initialized)
> + init_kprobe_blacklist();
> /*
>* If there exists a kprobe_blacklist, verify and
>* fail any probe registration in the prohibited area
> @@ -1816,6 +1867,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
> void *addr;
>
> if (kretprobe_blacklist_size) {
> + if (!kprobe_blacklist_initialized)
> + init_kprobe_blacklist();
Joonsoo reminds me that these calling points are not protected by kprobe_mutex,
thus we have to do something for avoiding concurrent initialization.
Perhaps, the easiest way is to protect init_kprobe_blacklist() by kprobe_mutex
and check kprobe_blacklist_initialized again in the top of that.
Thank you,
--
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/4] kprobes: delay blacklist symbol lookup until we actually need it
(2013/04/03 17:28), oskar.and...@sonymobile.com wrote:
+/* 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;
+
+ /*
+ * 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);
+ }
+ }
+ kprobe_blacklist_initialized = 1;
+}
+
#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
/*
* kprobe-ainsn.insn points to the copy of the instruction to be
@@ -1331,6 +1379,9 @@ 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 (!kprobe_blacklist_initialized)
+ init_kprobe_blacklist();
/*
* If there exists a kprobe_blacklist, verify and
* fail any probe registration in the prohibited area
@@ -1816,6 +1867,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
void *addr;
if (kretprobe_blacklist_size) {
+ if (!kprobe_blacklist_initialized)
+ init_kprobe_blacklist();
Joonsoo reminds me that these calling points are not protected by kprobe_mutex,
thus we have to do something for avoiding concurrent initialization.
Perhaps, the easiest way is to protect init_kprobe_blacklist() by kprobe_mutex
and check kprobe_blacklist_initialized again in the top of that.
Thank you,
--
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/4] kprobes: delay blacklist symbol lookup until we actually need it
On 08:44 Thu 04 Apr , Masami Hiramatsu wrote:
(2013/04/03 17:28), oskar.and...@sonymobile.com wrote:
+/* 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;
+
+ /*
+* 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);
+ }
+ }
+ kprobe_blacklist_initialized = 1;
+}
+
#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
/*
* kprobe-ainsn.insn points to the copy of the instruction to be
@@ -1331,6 +1379,9 @@ 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 (!kprobe_blacklist_initialized)
+ init_kprobe_blacklist();
/*
* If there exists a kprobe_blacklist, verify and
* fail any probe registration in the prohibited area
@@ -1816,6 +1867,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
void *addr;
if (kretprobe_blacklist_size) {
+ if (!kprobe_blacklist_initialized)
+ init_kprobe_blacklist();
Joonsoo reminds me that these calling points are not protected by
kprobe_mutex,
thus we have to do something for avoiding concurrent initialization.
Perhaps, the easiest way is to protect init_kprobe_blacklist() by kprobe_mutex
and check kprobe_blacklist_initialized again in the top of that.
Yes, you are right. I had a second look at Joonsoo's patch and I will
add a similar mutex for v2.
-Oskar
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[PATCH 1/4] kprobes: delay blacklist symbol lookup until we actually need it
From: Toby Collett
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.
Reviewed-by: Radovan Lekanovic
Signed-off-by: Toby Collett
Signed-off-by: Oskar Andero
---
kernel/kprobes.c | 91 +---
1 file changed, 53 insertions(+), 38 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index e35be53..71a6bee 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -68,6 +68,7 @@
#endif
static int kprobes_initialized;
+static int kprobe_blacklist_initialized;
static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
@@ -102,6 +103,53 @@ 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;
+
+ /*
+* 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,
+ , , , 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);
+ }
+ }
+ kprobe_blacklist_initialized = 1;
+}
+
#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
/*
* kprobe->ainsn.insn points to the copy of the instruction to be
@@ -1331,6 +1379,9 @@ 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 (!kprobe_blacklist_initialized)
+ init_kprobe_blacklist();
/*
* If there exists a kprobe_blacklist, verify and
* fail any probe registration in the prohibited area
@@ -1816,6 +1867,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
void *addr;
if (kretprobe_blacklist_size) {
+ if (!kprobe_blacklist_initialized)
+ init_kprobe_blacklist();
addr = kprobe_addr(>kp);
if (IS_ERR(addr))
return PTR_ERR(addr);
@@ -2065,11 +2118,6 @@ 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 +2127,6 @@ 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,
- , , , namebuf);
- if (!symbol_name)
- kb->range = 0;
- else
- kb->range = size;
- }
-
- if (kretprobe_blacklist_size) {
- /* lookup the function address from
[PATCH 1/4] kprobes: delay blacklist symbol lookup until we actually need it
From: Toby Collett toby.coll...@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.
Reviewed-by: Radovan Lekanovic radovan.lekano...@sonymobile.com
Signed-off-by: Toby Collett toby.coll...@sonymobile.com
Signed-off-by: Oskar Andero oskar.and...@sonymobile.com
---
kernel/kprobes.c | 91 +---
1 file changed, 53 insertions(+), 38 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index e35be53..71a6bee 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -68,6 +68,7 @@
#endif
static int kprobes_initialized;
+static int kprobe_blacklist_initialized;
static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
@@ -102,6 +103,53 @@ 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;
+
+ /*
+* 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);
+ }
+ }
+ kprobe_blacklist_initialized = 1;
+}
+
#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
/*
* kprobe-ainsn.insn points to the copy of the instruction to be
@@ -1331,6 +1379,9 @@ 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 (!kprobe_blacklist_initialized)
+ init_kprobe_blacklist();
/*
* If there exists a kprobe_blacklist, verify and
* fail any probe registration in the prohibited area
@@ -1816,6 +1867,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
void *addr;
if (kretprobe_blacklist_size) {
+ if (!kprobe_blacklist_initialized)
+ init_kprobe_blacklist();
addr = kprobe_addr(rp-kp);
if (IS_ERR(addr))
return PTR_ERR(addr);
@@ -2065,11 +2118,6 @@ 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 +2127,6 @@ 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
-
