[BProc] vmadump is using already freed memory

[Michal J. <mi...@ha...>]

There is a problem with vmadump_common.c "recycling" kernel memory.
In load_map it _does_ print a strange looking garbage in a case
of a failure (leaving me scratching my head for quite a while :-).
Here is a patch:

--- bproc-4.0.0pre6/vmadump/vmadump_common.c~	2004-06-22 12:24:20.000000000 -0600
+++ bproc-4.0.0pre6/vmadump/vmadump_common.c	2004-08-15 13:33:49.090716846 -0600
@@ -335,8 +335,8 @@ int vmadump_del_hook(struct vmadump_hook
 	if (h->hook == hook) {
 	    list_del(&h->list);
 	    up_write(&hook_lock);
-	    kfree(h);
 	    printk(KERN_INFO "vmadump: Unregistered hook \"%s\"\n", hook->tag);
+	    kfree(h);
 	    return 0;
 	}
     }
@@ -544,8 +544,8 @@ int load_map(struct vmadump_map_ctx *ctx
 	r = mmap_file(ctx, head, filename,
 		      PROT_READ|PROT_WRITE|PROT_EXEC, mmap_flags);
 	if (r) {
-	    kfree(filename);
 	    printk("vmadump: mmap failed: %s\n", filename);
+	    kfree(filename);
 	    return r;
 	}
 	kfree(filename);

The first chunk is not really needed but just in case if somebody
would like later to add a printout of 'h' to this printk. :-)
The second chunk is the real bug.

A quick scan through the rest of bproc code does not show up
similar troubles elsewhere but I was not very thorough.

   Michal