On Mon, Oct 25, 2021 at 05:05:03PM -0400, Steven Rostedt wrote:

On Mon, 25 Oct 2021 11:10:09 -0700
Alexei Starovoitov [off-list ref] wrote:

quoted

It looks like a churn that doesn't really address the problem.
If we were to allow long names then make it into a pointer and use 16 byte
as an optimized storage for short names. Any longer name would be a pointer.
In other words make it similar to dentry->d_iname.

That would be quite a bigger undertaking too, as it is assumed throughout
the kernel that the task->comm is TASK_COMM_LEN and is nul terminated. And
most locations that save the comm simply use a fixed size string of
TASK_COMM_LEN. Not saying its not feasible, but it would require a lot more
analysis of the impact by changing such a fundamental part of task struct
from a static to something requiring allocation.

Unless you are suggesting that we truncate like normal the 16 byte names
(to a max of 15 characters), and add a way to hold the entire name for
those locations that understand it.

Agreed -- this is a small change for what is already an "uncommon"
corner case. I don't think this needs to suddenly become an unbounded
string. :)

-- 
Kees Cook