PR/59056 CVS commit: src/tests/kernel/kqueue/write

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

The following reply was made to PR kern/59056; it has been noted by GNATS.

From: "Taylor R Campbell" <riastradh%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/59056 CVS commit: src/tests/kernel/kqueue/write
Date: Sat, 3 Oct 2026 21:06:05 +0000

 Module Name:	src
 Committed By:	riastradh
 Date:		Sat Oct  3 21:06:05 UTC 2026
 
 Modified Files:
 	src/tests/kernel/kqueue/write: t_pipe.c
 
 Log Message:
 kqueue/kernel/t_pipe: Fix newly failing test.
 
 If the read side of a pipe has been closed, then for the write side:
 - poll will set POLLOUT, not POLLNVAL (nor fail with EBADF), and
 - select will report writable, not fail with EBADF,
 because the write side is immediately writable and will fail with
 EPIPE/SIGPIPE -- it won't block if you try to write.
 
 So surely kqueue with EVFILT_WRITE should simply report immediately
 writable too, not fail with EBADF.  And that is what I caused to
 happen by simplifying and clarifying the code and fixing various edge
 cases.  (The bad response that this test was added to check is a
 kernel crash on null pointer dereference; that, fortunately, has not
 regressed.)
 
 PR kern/59056: poll POLLHUP bugs
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.2 -r1.3 src/tests/kernel/kqueue/write/t_pipe.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.