Re: [PATCH] Don't oops when unregistering unknown kprobes

[Frederik Deweerdt]

Le 26/04/05 21:57 +0530, Prasanna S Panchamukhi écrivit:
> This is wrong. You should call get_kprobe() with spin_lock().
>  
Right, corrected patch attached. It also sets flags to zero.

Signed-off-by: Frederik Deweerdt <frederik.deweerdt@xxxxxxxxxxx>

Regards,
Frederik

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--- linux-2.6.12-rc3/kernel/kprobes.c	2005-04-26 16:35:22.000000000 +0200
+++ linux-2.6.12-rc3-devel/kernel/kprobes.c	2005-04-26 23:18:47.000000000 +0200
@@ -106,13 +106,22 @@ rm_kprobe:
 
 void unregister_kprobe(struct kprobe *p)
 {
-	unsigned long flags;
+	unsigned long flags = 0;
+
+	spin_lock_irqsave(&kprobe_lock, flags);
+	if (!get_kprobe(p)) {
+		printk(KERN_WARNING "Warning: Attempt to unregister "
+					"unknown kprobe (addr:0x%lx)\n",
+					(unsigned long) p);
+		goto out;
+	}
 	arch_remove_kprobe(p);
 	spin_lock_irqsave(&kprobe_lock, flags);
 	*p->addr = p->opcode;
 	hlist_del(&p->hlist);
 	flush_icache_range((unsigned long) p->addr,
 			   (unsigned long) p->addr + sizeof(kprobe_opcode_t));
+out:
 	spin_unlock_irqrestore(&kprobe_lock, flags);
 }