kmod: prevent kmod_loop_msg overflow in __request_module()

commit 37252db6aa576c34fd794a5a54fb32d7a8b3a07a upstream.

Due to post-increment in condition of kmod_loop_msg in __request_module(),
the system log can be spammed by much more than 5 instances of the 'runaway
loop' message if the number of events triggering it makes the kmod_loop_msg
to overflow.

Fix that by making sure we never increment it past the threshold.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/kernel/kmod.c b/kernel/kmod.c
index 47613df..fabfe54 100644 (file)
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -114,10 +114,12 @@ int __request_module(bool wait, const char *fmt, ...)
        atomic_inc(&kmod_concurrent);
        if (atomic_read(&kmod_concurrent) > max_modprobes) {
                /* We may be blaming an innocent here, but unlikely */
-               if (kmod_loop_msg++ < 5)
+               if (kmod_loop_msg < 5) {
                        printk(KERN_ERR
                               "request_module: runaway loop modprobe %s\n",
                               module_name);
+                       kmod_loop_msg++;
+               }
                atomic_dec(&kmod_concurrent);
                return -ENOMEM;
        }