Re: [PATCH] mm/mseal: fix mseal documentation for 32-bit kernels

From: Matthew Wilcox

Date: Fri Jul 03 2026 - 20:39:29 EST


On Fri, Jul 03, 2026 at 10:25:07AM +0800, Leon Hwang wrote:
> Document the -EINTR return from mmap_write_lock_killable(), fix the

No, you don't understand the whole concept of "killable". If a
task receives a fatal signal, it dies before it returns to userspace.
So userspace never gets to see the -EINTR. It's fine to document inside
the kernel that function foo() can return -EINTR, but it's pointless to
document it for userspace.

This is how "killable" differs from "interruptible". Interruptible allows
non-fatal signals to wake a task, and then the task can see the -EINTR.
But many processes do not check the error code, and so read() and write()
(despite being documented as being able to return EINTR!) do not do so
in practise.