mirror of
https://github.com/linux-apfs/apfstests.git
synced 2026-05-01 15:01:44 -07:00
Dave Chinner
2529c9486a
Fully scripted conversion, see script in initial SPDX license commit message. tests/xfs/044 was hand massaged to remove duplicate copyright and divider lines before running the script. Signed-off-by: Dave Chinner <dchinner@redhat.com>
95 lines
2.5 KiB
Bash
Executable File
95 lines
2.5 KiB
Bash
Executable File
#! /bin/bash
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# SPDX-License-Identifier: GPL-2.0
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# Copyright (c) 2018 Red Hat, Inc. All Rights Reserved.
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#
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# FS QA Test 445
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#
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# Test the XFS filestreams allocator for use-after-free inode access. The
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# filestreams allocator uses the MRU and historically kept around unreferenced
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# inode pointers in each element. These pointers could outlive the inodes they
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# referred to and thus lead to access of freed or reused memory when the MRU
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# element was reaped. Test for this problem by performing filestream allocations
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# against short-lived parent directory inodes.
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#
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# Note that some form of kernel debug mechanism for use-after-free detection
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# (i.e., KASAN) is required for this test to reproduce the original problem.
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# This is because XFS uses a kmem cache for xfs_inode objects which means that
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# the backing pages for freed inodes may still reside in the cache with the
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# freed inodes in a partially initialized state.
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#
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seq=`basename $0`
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seqres=$RESULT_DIR/$seq
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echo "QA output created by $seq"
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here=`pwd`
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tmp=/tmp/$$
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status=1 # failure is the default!
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trap "_cleanup; exit \$status" 0 1 2 3 15
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_cleanup()
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{
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cd /
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rm -f $tmp.*
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}
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# get standard environment, filters and checks
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. ./common/rc
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. ./common/filter
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. ./common/filestreams
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# remove previous $seqres.full before test
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rm -f $seqres.full
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# real QA test starts here
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drop_caches()
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{
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while [ true ]; do
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echo 2 > /proc/sys/vm/drop_caches
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sleep 1
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done
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}
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# Modify as appropriate.
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_supported_fs generic
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_supported_os Linux
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_require_scratch_size $((2*1024*1024)) # kb
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# check for filestreams
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_check_filestreams_support || _notrun "filestreams not available"
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# use small AGs for frequent stream switching
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_scratch_mkfs_xfs -d agsize=20m,size=2g >> $seqres.full 2>&1 ||
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_fail "mkfs failed"
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_scratch_mount "-o filestreams"
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# start background inode reclaim
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drop_caches &
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pid=$!
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# Stress the filestreams allocator via continuous allocation to a file under
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# different parent dirs. Remove the old dirs as the file is moved so the MRU
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# references point to an unlinked inode by the time they are removed. If the
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# old dir inodes are reclaimed and associated memory reused, MRU cleanup can
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# access the inode after it's been freed.
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dir=$SCRATCH_MNT
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for i in $(seq 0 90); do
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mkdir -p $dir/$i
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$XFS_IO_PROG -fc "falloc $(($i * 20))m 20m" $dir/$i/file
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mkdir -p $dir/$((i + 1))
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mv $dir/$i/file $dir/$((i + 1))/file
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rmdir $dir/$i
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# throttle to ensure this loop sees several cache reclaims
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sleep 0.1
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done
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kill $pid 2> /dev/null
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wait $pid 2> /dev/null
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echo Silence is golden
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# success, all done
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status=0
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exit
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