Re: [PATCH 1/2] treewide: fix memory corruptions when TASK_COMM_LEN!= 16

From: Jan Engelhardt
Date: Tue Jan 31 2012 - 21:15:50 EST



On Wednesday 2012-02-01 02:49, Andrew Morton wrote:
>>
>> Did my patch not change the existing code sites using ->comm
>> to always copy at most min(userbufsize aka 16, sizeof(t->comm)) bytes,
>> thereby keeping the promise to userspace while at the same time
>> making TASK_COMM_LEN's value freely choosable?
>
>That change is pretty pointless as long as we don't provide APIs to let
>userspace access the expanded size. And I've explained why we cannot
>alter the existing APIs.

Ah yes, indeed. My reason for augmenting the size of t->comm was so
that `ps afx` could show a more complete name of certain kernel
threads' names. In this case, the kernel delivers the name via
procfs via seq_printf("%s, t->comm), as do a few debug statements
in the fashion of pr_debug("%s/%u ate my CPU", t->comm, t->pid).
So maybe it was not /completely/ pointless.
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