[LU-206] Memory corruption due to MMP (1.8.5)

Wed, 20 Apr 2011 08:49:25 +0000

I have been chasing a weird bug with MMP on 2.6.39-rc1 (i want to push MMP upstream) and it turns out to be an horrible memory corruption which can impact any kernels.

+       mmpd_data = kmalloc(sizeof(struct mmpd_data *), GFP_KERNEL);
                                   ^^^^^^^^^^^^^^^^^^^
                                OUCH!!! should be sizeof(struct mmpd_data)
+       if (!mmpd_data) {
+               ext3_warning(sb, KERN_ERR, "not enough memory for mmpd_data");
+               goto failed;
+       }   
+       mmpd_data->sb = sb; 
+       mmpd_data->bh = bh;

The memory corruption was introduced by bugzilla ticket 22117 in 1.8.5.
This issue can cause all sorts of oops everywhere in the kernel.

Whamcloud Community JIRA

[LU-206] Memory corruption due to MMP (1.8.5)