rcu: Use true/false for return in rcu_nocb_adopt_orphan_cbs()

[deliverable/linux.git] / kernel / kprobes.c

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 3214289df5a7a8f6917718a9a00f418794efeab1..3995f546d0f3f9c7bc845e7053f7a099088108a2 100644 (file)
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1778,7 +1778,18 @@ static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
        unsigned long hash, flags = 0;
        struct kretprobe_instance *ri;
 
-       /*TODO: consider to only swap the RA after the last pre_handler fired */
+       /*
+        * To avoid deadlocks, prohibit return probing in NMI contexts,
+        * just skip the probe and increase the (inexact) 'nmissed'
+        * statistical counter, so that the user is informed that
+        * something happened:
+        */
+       if (unlikely(in_nmi())) {
+               rp->nmissed++;
+               return 0;
+       }
+
+       /* TODO: consider to only swap the RA after the last pre_handler fired */
        hash = hash_ptr(current, KPROBE_HASH_BITS);
        raw_spin_lock_irqsave(&rp->lock, flags);
        if (!hlist_empty(&rp->free_instances)) {
@@ -2037,19 +2048,23 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
 {
        unsigned long *iter;
        struct kprobe_blacklist_entry *ent;
-       unsigned long offset = 0, size = 0;
+       unsigned long entry, offset = 0, size = 0;
 
        for (iter = start; iter < end; iter++) {
-               if (!kallsyms_lookup_size_offset(*iter, &size, &offset)) {
-                       pr_err("Failed to find blacklist %p\n", (void *)*iter);
+               entry = arch_deref_entry_point((void *)*iter);
+
+               if (!kernel_text_address(entry) ||
+                   !kallsyms_lookup_size_offset(entry, &size, &offset)) {
+                       pr_err("Failed to find blacklist at %p\n",
+                               (void *)entry);
                        continue;
                }
 
                ent = kmalloc(sizeof(*ent), GFP_KERNEL);
                if (!ent)
                        return -ENOMEM;
-               ent->start_addr = *iter;
-               ent->end_addr = *iter + size;
+               ent->start_addr = entry;
+               ent->end_addr = entry + size;
                INIT_LIST_HEAD(&ent->list);
                list_add_tail(&ent->list, &kprobe_blacklist);
        }