releases/3.1.1/kmod-prevent-kmod_loop_msg-overflow-in-__request_module.patch

   1 From 37252db6aa576c34fd794a5a54fb32d7a8b3a07a Mon Sep 17 00:00:00 2001
   2 From: Jiri Kosina <jkosina@suse.cz>
   3 Date: Wed, 26 Oct 2011 13:10:39 +1030
   4 Subject: kmod: prevent kmod_loop_msg overflow in __request_module()
   5
   6 From: Jiri Kosina <jkosina@suse.cz>
   7
   8 commit 37252db6aa576c34fd794a5a54fb32d7a8b3a07a upstream.
   9
  10 Due to post-increment in condition of kmod_loop_msg in __request_module(),
  11 the system log can be spammed by much more than 5 instances of the 'runaway
  12 loop' message if the number of events triggering it makes the kmod_loop_msg
  13 to overflow.
  14
  15 Fix that by making sure we never increment it past the threshold.
  16
  17 Signed-off-by: Jiri Kosina <jkosina@suse.cz>
  18 Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
  19 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  20
  21 ---
  22  kernel/kmod.c |    4 +++-
  23  1 file changed, 3 insertions(+), 1 deletion(-)
  24
  25 --- a/kernel/kmod.c
  26 +++ b/kernel/kmod.c
  27 @@ -114,10 +114,12 @@ int __request_module(bool wait, const ch
  28         atomic_inc(&kmod_concurrent);
  29         if (atomic_read(&kmod_concurrent) > max_modprobes) {
  30                 /* We may be blaming an innocent here, but unlikely */
  31 -               if (kmod_loop_msg++ < 5)
  32 +               if (kmod_loop_msg < 5) {
  33                         printk(KERN_ERR
  34                                "request_module: runaway loop modprobe %s\n",
  35                                module_name);
  36 +                       kmod_loop_msg++;
  37 +               }
  38                 atomic_dec(&kmod_concurrent);
  39                 return -ENOMEM;
  40         }