Re: [RFC PATCH] generic: test PF_MEMALLOC interfering with accounting file write

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Thu, Mar 12, 2020 at 03:14:37PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> Add a regression test for the bug fixed by commit 10a98cb16d80 ("xfs:
> clear PF_MEMALLOC before exiting xfsaild thread").
> 
> Signed-off-by: Eric Biggers <ebiggers@google.com>
> ---
> 
> RFC for now since the commit is in xfs/for-next only, and I'm not sure
> the commit ID is stable.

It's not stable until it lands in Linus tree, unfortunately. :(

>  common/config         |  1 +
>  common/rc             | 11 ++++++++
>  tests/generic/901     | 60 +++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/901.out |  2 ++
>  tests/generic/group   |  1 +
>  5 files changed, 75 insertions(+)
>  create mode 100644 tests/generic/901
>  create mode 100644 tests/generic/901.out
> 
> diff --git a/common/config b/common/config
> index 1116cb995..8023273da 100644
> --- a/common/config
> +++ b/common/config
> @@ -220,6 +220,7 @@ export DUPEREMOVE_PROG="$(type -P duperemove)"
>  export CC_PROG="$(type -P cc)"
>  export FSVERITY_PROG="$(type -P fsverity)"
>  export OPENSSL_PROG="$(type -P openssl)"
> +export ACCTON_PROG="$(type -P accton)"
>  
>  # use 'udevadm settle' or 'udevsettle' to wait for lv to be settled.
>  # newer systems have udevadm command but older systems like RHEL5 don't.
> diff --git a/common/rc b/common/rc
> index 454f5ccf5..0bc4b14f2 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -4168,6 +4168,17 @@ _check_xfs_scrub_does_unicode() {
>  	return 0
>  }
>  
> +# Require the 'accton' userspace tool and CONFIG_BSD_PROCESS_ACCT=y.
> +_require_bsd_process_accounting()
> +{
> +	_require_command "$ACCTON_PROG" accton
> +	$ACCTON_PROG on &> $tmp.test_accton
> +	cat $tmp.test_accton >> $seqres.full
> +	if grep 'Function not implemented' $tmp.test_accton; then
> +		_notrun "BSD process accounting support unavailable"
> +	fi

Should we run "$ACCTON_PROG off" here to turn process accounting back
off until the test needs it again?

Otherwise the logic looks sound.  Thanks for writing this up!

--D

> +}
> +
>  init_rc
>  
>  ################################################################################
> diff --git a/tests/generic/901 b/tests/generic/901
> new file mode 100644
> index 000000000..c59300f1b
> --- /dev/null
> +++ b/tests/generic/901
> @@ -0,0 +1,60 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright 2020 Google LLC
> +#
> +# FS QA Test No. 901
> +#
> +# Regression test for the bug fixed by commit 10a98cb16d80 ("xfs: clear
> +# PF_MEMALLOC before exiting xfsaild thread").  If the bug exists, a kernel
> +# WARNING should be triggered.  See the commit message for details.
> +#
> +seq=`basename $0`
> +seqres=$RESULT_DIR/$seq
> +echo "QA output created by $seq"
> +
> +here=`pwd`
> +tmp=/tmp/$$
> +status=1	# failure is the default!
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +_cleanup()
> +{
> +	$ACCTON_PROG off >> $seqres.full
> +	rm -f $tmp.*
> +}
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +. ./common/filter
> +
> +# remove previous $seqres.full before test
> +rm -f $seqres.full
> +
> +# real QA test starts here
> +_supported_fs generic
> +_supported_os Linux
> +_require_bsd_process_accounting
> +_require_chattr S
> +_require_test
> +_require_scratch
> +
> +# To trigger the bug we must unmount a filesystem while BSD process accounting
> +# is enabled.  The accounting file must also be located on a different
> +# filesystem and have the sync flag set.
> +
> +accounting_file=$TEST_DIR/$seq
> +
> +rm -f $accounting_file
> +touch $accounting_file
> +$CHATTR_PROG +S $accounting_file
> +
> +_scratch_mkfs &>> $seqres.full
> +$ACCTON_PROG $accounting_file >> $seqres.full
> +_scratch_mount
> +_scratch_unmount
> +$ACCTON_PROG off >> $seqres.full
> +
> +echo "Silence is golden"
> +
> +status=0
> +exit
> diff --git a/tests/generic/901.out b/tests/generic/901.out
> new file mode 100644
> index 000000000..b206bc11d
> --- /dev/null
> +++ b/tests/generic/901.out
> @@ -0,0 +1,2 @@
> +QA output created by 901
> +Silence is golden
> diff --git a/tests/generic/group b/tests/generic/group
> index dc95b77b3..61a679793 100644
> --- a/tests/generic/group
> +++ b/tests/generic/group
> @@ -595,3 +595,4 @@
>  591 auto quick rw pipe splice
>  592 auto quick encrypt
>  593 auto quick encrypt
> +901 auto quick
> -- 
> 2.25.1
>