kprobes: tracing/kprobes: Fix to kill kprobes on initmem after boot

commit 82d083ab60c3693201c6f5c7a5f23a6ed422098d upstream.

Since kprobe_event= cmdline option allows user to put kprobes on the
functions in initmem, kprobe has to make such probes gone after boot.
Currently the probes on the init functions in modules will be handled
by module callback, but the kernel init text isn't handled.
Without this, kprobes may access non-exist text area to disable or
remove it.

Link: https://lkml.kernel.org/r/159972810544.428528.1839307531600646955.stgit@devnote2
Fixes: 970988e19eb0 ("tracing/kprobe: Add kprobe_event= boot parameter")
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 6adf90f248d701a63f537644feb8ccee15174878..d6c83de361e47e03d2a90ec9b0e0536c569158af 100644 (file)
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -369,6 +369,8 @@ void unregister_kretprobes(struct kretprobe **rps, int num);
 void kprobe_flush_task(struct task_struct *tk);
 void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
 
+void kprobe_free_init_mem(void);
+
 int disable_kprobe(struct kprobe *kp);
 int enable_kprobe(struct kprobe *kp);
 
@@ -426,6 +428,9 @@ static inline void unregister_kretprobes(struct kretprobe **rps, int num)
 static inline void kprobe_flush_task(struct task_struct *tk)
 {
 }
+static inline void kprobe_free_init_mem(void)
+{
+}
 static inline int disable_kprobe(struct kprobe *kp)
 {
        return -ENOSYS;

diff --git a/init/main.c b/init/main.c
index 883ded3638e597b30b0ff8fac560d1ead897fcd0..e214cdd18c2859c97d89691acfd7c8a1987aa87a 100644 (file)
--- a/init/main.c
+++ b/init/main.c
@@ -33,6 +33,7 @@
 #include <linux/nmi.h>
 #include <linux/percpu.h>
 #include <linux/kmod.h>
+#include <linux/kprobes.h>
 #include <linux/vmalloc.h>
 #include <linux/kernel_stat.h>
 #include <linux/start_kernel.h>
@@ -1401,6 +1402,7 @@ static int __ref kernel_init(void *unused)
        kernel_init_freeable();
        /* need to finish all async __init code before freeing the memory */
        async_synchronize_full();
+       kprobe_free_init_mem();
        ftrace_free_init_mem();
        free_initmem();
        mark_readonly();

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index e5dc8330651b65918cc59e3e24e3bfbd8e797656..d0bf0ad425df53a47dfdfe76d1bf8fcc84dc31c7 100644 (file)
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2406,6 +2406,28 @@ static struct notifier_block kprobe_module_nb = {
 extern unsigned long __start_kprobe_blacklist[];
 extern unsigned long __stop_kprobe_blacklist[];
 
+void kprobe_free_init_mem(void)
+{
+       void *start = (void *)(&__init_begin);
+       void *end = (void *)(&__init_end);
+       struct hlist_head *head;
+       struct kprobe *p;
+       int i;
+
+       mutex_lock(&kprobe_mutex);
+
+       /* Kill all kprobes on initmem */
+       for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
+               head = &kprobe_table[i];
+               hlist_for_each_entry(p, head, hlist) {
+                       if (start <= (void *)p->addr && (void *)p->addr < end)
+                               kill_kprobe(p);
+               }
+       }
+
+       mutex_unlock(&kprobe_mutex);
+}
+
 static int __init init_kprobes(void)
 {
        int i, err = 0;