only for fexecve?

Posted Nov 27, 2024 15:33 UTC (Wed) by shironeko (subscriber, #159952)
Parent article: The kernel's command-line commotion

This change is only for fexecve right? since the current behavior is just a number (not even unique), I'm not sure how going with either of the approaches will break any users, or subvert user expectation?

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only for fexecve?

Posted Nov 27, 2024 20:17 UTC (Wed) by ebiederm (subscriber, #35028) [Link]

Yes, only for the case where no filename is supplied to execveat.

There are cases like login shells where argv[0] must take a value that is not really appropriate for use as task->comm.

So no. Userspace won't be broken. There are just cases where slowing down user space using open followed by extra followed by execveat will have a different task->comm.

The silliness of using the ascii string representing the file descriptor number is going away, and that is good.

only for fexecve?

Posted Nov 27, 2024 21:25 UTC (Wed) by jkingweb (subscriber, #113039) [Link]

In short, systemd wants to use fexecve to cleanly avoid data races, but the lack of reliable comm data makes this impractical. The change in the kernel doesn't break anything, but systemd switching to fexecve even with this change would break things.