From: Masami Hiramatsu mhiramat@kernel.org
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@devn...
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
--- include/linux/kprobes.h | 5 +++++ init/main.c | 2 ++ kernel/kprobes.c | 22 ++++++++++++++++++++++ 3 files changed, 29 insertions(+)
--- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -369,6 +369,8 @@ void unregister_kretprobes(struct kretpr 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 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; --- 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 *unuse 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(); --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2406,6 +2406,28 @@ static struct notifier_block kprobe_modu 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;