* [PATCH -tip 1/4] kprobes: Lock kprobe_mutex while showing kprobe_blacklist
2020-03-26 14:49 [PATCH -tip 0/4] kprobes: Support __kprobes and NOKPROBE_SYMBOL in modules Masami Hiramatsu
@ 2020-03-26 14:49 ` Masami Hiramatsu
2020-03-26 14:49 ` [PATCH -tip 2/4] kprobes: Support __kprobes blacklist in modules Masami Hiramatsu
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Masami Hiramatsu @ 2020-03-26 14:49 UTC (permalink / raw)
To: Ingo Molnar, Thomas Gleixner
Cc: LKML, x86, Paul McKenney, Josh Poimboeuf, Joel Fernandes,
Steven Rostedt, Alexei Starovoitov, Frederic Weisbecker,
Mathieu Desnoyers, Brian Gerst, Juergen Gross, Alexandre Chartre,
Peter Zijlstra, Tom Lendacky, Paolo Bonzini
Lock kprobe_mutex while showing kprobe_blacklist to prevent
updating the kprobe_blacklist.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
kernel/kprobes.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 2625c241ac00..570d60827656 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2420,6 +2420,7 @@ static const struct file_operations debugfs_kprobes_operations = {
/* kprobes/blacklist -- shows which functions can not be probed */
static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
{
+ mutex_lock(&kprobe_mutex);
return seq_list_start(&kprobe_blacklist, *pos);
}
@@ -2446,10 +2447,15 @@ static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
return 0;
}
+static void kprobe_blacklist_seq_stop(struct seq_file *f, void *v)
+{
+ mutex_unlock(&kprobe_mutex);
+}
+
static const struct seq_operations kprobe_blacklist_seq_ops = {
.start = kprobe_blacklist_seq_start,
.next = kprobe_blacklist_seq_next,
- .stop = kprobe_seq_stop, /* Reuse void function */
+ .stop = kprobe_blacklist_seq_stop,
.show = kprobe_blacklist_seq_show,
};
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH -tip 2/4] kprobes: Support __kprobes blacklist in modules
2020-03-26 14:49 [PATCH -tip 0/4] kprobes: Support __kprobes and NOKPROBE_SYMBOL in modules Masami Hiramatsu
2020-03-26 14:49 ` [PATCH -tip 1/4] kprobes: Lock kprobe_mutex while showing kprobe_blacklist Masami Hiramatsu
@ 2020-03-26 14:49 ` Masami Hiramatsu
2020-03-26 14:50 ` [PATCH -tip 3/4] kprobes: Support NOKPROBE_SYMBOL() " Masami Hiramatsu
2020-03-26 14:50 ` [PATCH -tip 4/4] samples/kprobes: Add __kprobes and NOKPROBE_SYMBOL() for handlers Masami Hiramatsu
3 siblings, 0 replies; 5+ messages in thread
From: Masami Hiramatsu @ 2020-03-26 14:49 UTC (permalink / raw)
To: Ingo Molnar, Thomas Gleixner
Cc: LKML, x86, Paul McKenney, Josh Poimboeuf, Joel Fernandes,
Steven Rostedt, Alexei Starovoitov, Frederic Weisbecker,
Mathieu Desnoyers, Brian Gerst, Juergen Gross, Alexandre Chartre,
Peter Zijlstra, Tom Lendacky, Paolo Bonzini
Support __kprobes attribute for blacklist functions in modules.
The __kprobes attribute functions are stored in .kprobes.text
section.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
include/linux/module.h | 4 ++++
kernel/kprobes.c | 42 ++++++++++++++++++++++++++++++++++++++++++
kernel/module.c | 4 ++++
3 files changed, 50 insertions(+)
diff --git a/include/linux/module.h b/include/linux/module.h
index 1ad393e62bef..369c354f9207 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -489,6 +489,10 @@ struct module {
unsigned int num_ftrace_callsites;
unsigned long *ftrace_callsites;
#endif
+#ifdef CONFIG_KPROBES
+ void *kprobes_text_start;
+ unsigned int kprobes_text_size;
+#endif
#ifdef CONFIG_LIVEPATCH
bool klp; /* Is this a livepatch module? */
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 570d60827656..b7549992b9bd 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2179,6 +2179,19 @@ int kprobe_add_area_blacklist(unsigned long start, unsigned long end)
return 0;
}
+/* Remove all symbols in given area from kprobe blacklist */
+static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
+{
+ struct kprobe_blacklist_entry *ent, *n;
+
+ list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
+ if (ent->start_addr < start || ent->start_addr >= end)
+ continue;
+ list_del(&ent->list);
+ kfree(ent);
+ }
+}
+
int __init __weak arch_populate_kprobe_blacklist(void)
{
return 0;
@@ -2215,6 +2228,28 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
return ret ? : arch_populate_kprobe_blacklist();
}
+static void add_module_kprobe_blacklist(struct module *mod)
+{
+ unsigned long start, end;
+
+ start = (unsigned long)mod->kprobes_text_start;
+ if (start) {
+ end = start + mod->kprobes_text_size;
+ kprobe_add_area_blacklist(start, end);
+ }
+}
+
+static void remove_module_kprobe_blacklist(struct module *mod)
+{
+ unsigned long start, end;
+
+ start = (unsigned long)mod->kprobes_text_start;
+ if (start) {
+ end = start + mod->kprobes_text_size;
+ kprobe_remove_area_blacklist(start, end);
+ }
+}
+
/* Module notifier call back, checking kprobes on the module */
static int kprobes_module_callback(struct notifier_block *nb,
unsigned long val, void *data)
@@ -2225,6 +2260,11 @@ static int kprobes_module_callback(struct notifier_block *nb,
unsigned int i;
int checkcore = (val == MODULE_STATE_GOING);
+ if (val == MODULE_STATE_COMING) {
+ mutex_lock(&kprobe_mutex);
+ add_module_kprobe_blacklist(mod);
+ mutex_unlock(&kprobe_mutex);
+ }
if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
return NOTIFY_DONE;
@@ -2255,6 +2295,8 @@ static int kprobes_module_callback(struct notifier_block *nb,
kill_kprobe(p);
}
}
+ if (val == MODULE_STATE_GOING)
+ remove_module_kprobe_blacklist(mod);
mutex_unlock(&kprobe_mutex);
return NOTIFY_DONE;
}
diff --git a/kernel/module.c b/kernel/module.c
index 33569a01d6e1..f7712a923d63 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3193,6 +3193,10 @@ static int find_module_sections(struct module *mod, struct load_info *info)
mod->ei_funcs = section_objs(info, "_error_injection_whitelist",
sizeof(*mod->ei_funcs),
&mod->num_ei_funcs);
+#endif
+#ifdef CONFIG_KPROBES
+ mod->kprobes_text_start = section_objs(info, ".kprobes.text", 1,
+ &mod->kprobes_text_size);
#endif
mod->extable = section_objs(info, "__ex_table",
sizeof(*mod->extable), &mod->num_exentries);
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH -tip 3/4] kprobes: Support NOKPROBE_SYMBOL() in modules
2020-03-26 14:49 [PATCH -tip 0/4] kprobes: Support __kprobes and NOKPROBE_SYMBOL in modules Masami Hiramatsu
2020-03-26 14:49 ` [PATCH -tip 1/4] kprobes: Lock kprobe_mutex while showing kprobe_blacklist Masami Hiramatsu
2020-03-26 14:49 ` [PATCH -tip 2/4] kprobes: Support __kprobes blacklist in modules Masami Hiramatsu
@ 2020-03-26 14:50 ` Masami Hiramatsu
2020-03-26 14:50 ` [PATCH -tip 4/4] samples/kprobes: Add __kprobes and NOKPROBE_SYMBOL() for handlers Masami Hiramatsu
3 siblings, 0 replies; 5+ messages in thread
From: Masami Hiramatsu @ 2020-03-26 14:50 UTC (permalink / raw)
To: Ingo Molnar, Thomas Gleixner
Cc: LKML, x86, Paul McKenney, Josh Poimboeuf, Joel Fernandes,
Steven Rostedt, Alexei Starovoitov, Frederic Weisbecker,
Mathieu Desnoyers, Brian Gerst, Juergen Gross, Alexandre Chartre,
Peter Zijlstra, Tom Lendacky, Paolo Bonzini
Support NOKPROBE_SYMBOL() in modules. NOKPROBE_SYMBOL() records
only symbol address in "_kprobe_blacklist" section in the
module.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
include/linux/module.h | 2 ++
kernel/kprobes.c | 17 +++++++++++++++++
kernel/module.c | 3 +++
3 files changed, 22 insertions(+)
diff --git a/include/linux/module.h b/include/linux/module.h
index 369c354f9207..1192097c9a69 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -492,6 +492,8 @@ struct module {
#ifdef CONFIG_KPROBES
void *kprobes_text_start;
unsigned int kprobes_text_size;
+ unsigned long *kprobe_blacklist;
+ unsigned int num_kprobe_blacklist;
#endif
#ifdef CONFIG_LIVEPATCH
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index b7549992b9bd..9eb5acf0a9f3 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2192,6 +2192,11 @@ static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
}
}
+static void kprobe_remove_ksym_blacklist(unsigned long entry)
+{
+ kprobe_remove_area_blacklist(entry, entry + 1);
+}
+
int __init __weak arch_populate_kprobe_blacklist(void)
{
return 0;
@@ -2231,6 +2236,12 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
static void add_module_kprobe_blacklist(struct module *mod)
{
unsigned long start, end;
+ int i;
+
+ if (mod->kprobe_blacklist) {
+ for (i = 0; i < mod->num_kprobe_blacklist; i++)
+ kprobe_add_ksym_blacklist(mod->kprobe_blacklist[i]);
+ }
start = (unsigned long)mod->kprobes_text_start;
if (start) {
@@ -2242,6 +2253,12 @@ static void add_module_kprobe_blacklist(struct module *mod)
static void remove_module_kprobe_blacklist(struct module *mod)
{
unsigned long start, end;
+ int i;
+
+ if (mod->kprobe_blacklist) {
+ for (i = 0; i < mod->num_kprobe_blacklist; i++)
+ kprobe_remove_ksym_blacklist(mod->kprobe_blacklist[i]);
+ }
start = (unsigned long)mod->kprobes_text_start;
if (start) {
diff --git a/kernel/module.c b/kernel/module.c
index f7712a923d63..7be011dacd8a 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3197,6 +3197,9 @@ static int find_module_sections(struct module *mod, struct load_info *info)
#ifdef CONFIG_KPROBES
mod->kprobes_text_start = section_objs(info, ".kprobes.text", 1,
&mod->kprobes_text_size);
+ mod->kprobe_blacklist = section_objs(info, "_kprobe_blacklist",
+ sizeof(unsigned long),
+ &mod->num_kprobe_blacklist);
#endif
mod->extable = section_objs(info, "__ex_table",
sizeof(*mod->extable), &mod->num_exentries);
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH -tip 4/4] samples/kprobes: Add __kprobes and NOKPROBE_SYMBOL() for handlers.
2020-03-26 14:49 [PATCH -tip 0/4] kprobes: Support __kprobes and NOKPROBE_SYMBOL in modules Masami Hiramatsu
` (2 preceding siblings ...)
2020-03-26 14:50 ` [PATCH -tip 3/4] kprobes: Support NOKPROBE_SYMBOL() " Masami Hiramatsu
@ 2020-03-26 14:50 ` Masami Hiramatsu
3 siblings, 0 replies; 5+ messages in thread
From: Masami Hiramatsu @ 2020-03-26 14:50 UTC (permalink / raw)
To: Ingo Molnar, Thomas Gleixner
Cc: LKML, x86, Paul McKenney, Josh Poimboeuf, Joel Fernandes,
Steven Rostedt, Alexei Starovoitov, Frederic Weisbecker,
Mathieu Desnoyers, Brian Gerst, Juergen Gross, Alexandre Chartre,
Peter Zijlstra, Tom Lendacky, Paolo Bonzini
Add __kprobes and NOKPROBE_SYMBOL() for sample
kprobe handlers.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
samples/kprobes/kprobe_example.c | 6 ++++--
samples/kprobes/kretprobe_example.c | 2 ++
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/samples/kprobes/kprobe_example.c b/samples/kprobes/kprobe_example.c
index d693c23a85e8..501911d1b327 100644
--- a/samples/kprobes/kprobe_example.c
+++ b/samples/kprobes/kprobe_example.c
@@ -25,7 +25,7 @@ static struct kprobe kp = {
};
/* kprobe pre_handler: called just before the probed instruction is executed */
-static int handler_pre(struct kprobe *p, struct pt_regs *regs)
+static int __kprobes handler_pre(struct kprobe *p, struct pt_regs *regs)
{
#ifdef CONFIG_X86
pr_info("<%s> pre_handler: p->addr = 0x%p, ip = %lx, flags = 0x%lx\n",
@@ -54,7 +54,7 @@ static int handler_pre(struct kprobe *p, struct pt_regs *regs)
}
/* kprobe post_handler: called after the probed instruction is executed */
-static void handler_post(struct kprobe *p, struct pt_regs *regs,
+static void __kprobes handler_post(struct kprobe *p, struct pt_regs *regs,
unsigned long flags)
{
#ifdef CONFIG_X86
@@ -90,6 +90,8 @@ static int handler_fault(struct kprobe *p, struct pt_regs *regs, int trapnr)
/* Return 0 because we don't handle the fault. */
return 0;
}
+/* NOKPROBE_SYMBOL() is also available */
+NOKPROBE_SYMBOL(handler_fault);
static int __init kprobe_init(void)
{
diff --git a/samples/kprobes/kretprobe_example.c b/samples/kprobes/kretprobe_example.c
index 186315ca88b3..013e8e6ebae9 100644
--- a/samples/kprobes/kretprobe_example.c
+++ b/samples/kprobes/kretprobe_example.c
@@ -48,6 +48,7 @@ static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
data->entry_stamp = ktime_get();
return 0;
}
+NOKPROBE_SYMBOL(entry_handler);
/*
* Return-probe handler: Log the return value and duration. Duration may turn
@@ -67,6 +68,7 @@ static int ret_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
func_name, retval, (long long)delta);
return 0;
}
+NOKPROBE_SYMBOL(ret_handler);
static struct kretprobe my_kretprobe = {
.handler = ret_handler,
^ permalink raw reply related [flat|nested] 5+ messages in thread