diff options
| -rw-r--r-- | kernel/notifier.c | 16 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 10 |
2 files changed, 26 insertions, 0 deletions
diff --git a/kernel/notifier.c b/kernel/notifier.c index 823be11584e..143fdd77dbf 100644 --- a/kernel/notifier.c +++ b/kernel/notifier.c @@ -21,6 +21,10 @@ BLOCKING_NOTIFIER_HEAD(reboot_notifier_list); static int notifier_chain_register(struct notifier_block **nl, struct notifier_block *n) { + if (!kernel_text_address((unsigned long)n->notifier_call)) { + WARN(1, "Invalid notifier registered!"); + return 0; + } while ((*nl) != NULL) { if (n->priority > (*nl)->priority) break; @@ -34,6 +38,10 @@ static int notifier_chain_register(struct notifier_block **nl, static int notifier_chain_cond_register(struct notifier_block **nl, struct notifier_block *n) { + if (!kernel_text_address((unsigned long)n->notifier_call)) { + WARN(1, "Invalid notifier registered!"); + return 0; + } while ((*nl) != NULL) { if ((*nl) == n) return 0; @@ -82,6 +90,14 @@ static int __kprobes notifier_call_chain(struct notifier_block **nl, while (nb && nr_to_call) { next_nb = rcu_dereference(nb->next); + +#ifdef CONFIG_DEBUG_NOTIFIERS + if (!kernel_text_address((unsigned long)nb->notifier_call)) { + WARN(1, "Invalid notifier called!"); + nb = next_nb; + continue; + } +#endif ret = nb->notifier_call(nb, val, v); if (nr_calls) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 8b5a7d304a5..342858fbabb 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -536,6 +536,16 @@ config DEBUG_SG If unsure, say N. +config DEBUG_NOTIFIERS + bool "Debug notifier call chains" + depends on DEBUG_KERNEL + help + Enable this to turn on sanity checking for notifier call chains. + This is most useful for kernel developers to make sure that + modules properly unregister themselves from notifier chains. + This is a relatively cheap check but if you care about maximum + performance, say N. + config FRAME_POINTER bool "Compile the kernel with frame pointers" depends on DEBUG_KERNEL && \ |