kern/57248: rumpfs test failure on sparc64

[martin%NetBSD.org@localhost]

>Number:         57248
>Category:       kern
>Synopsis:       rumpfs test failure on sparc64
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Feb 28 10:20:00 +0000 2023
>Originator:     Martin Husemann
>Release:        NetBSD 10.99.2
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD thirdstage.duskware.de 10.99.2 NetBSD 10.99.2 (MODULAR) #619: Mon Feb 27 14:46:07 CET 2023 martin%thirdstage.duskware.de@localhost:/usr/src/sys/arch/sparc64/compile/MODULAR sparc64
Architecture: sparc64
Machine: sparc64
>Description:

There is an obscure test failure in the sparc64 test runs:

 rumpfs_wrrd_after_unlink, failed, /usr/src/tests/fs/vfs/t_io.c:211: rump_sys_pwrite(fd, &value, sizeof(value), 654321): No space left on device

in /usr/tests/fs/vfs/t_io, leading to:

Summary for 1 test programs:
    139 passed test cases.
    1 failed test cases.
    0 expected failed test cases.
    0 skipped test cases.

The test program has two other invocations of rump_sys_pwrite(), but with a
lot smaller offsets (pagesize and pagesize-1).

I guess something goes wrong in rump argument marshalling for rumpfs,
but I am a bit lost in how to debug this further - any hints welcome.

>How-To-Repeat:
s/a

>Fix:
n/a