[bug report] xfs/078 failure

Shin'ichiro Kawasaki <[email protected]>
Newsgroups org.kernel.vger.fstests,org.kernel.vger.linux-xfs
Message-ID <ahA8uwU8G83YVYU8@shinmob> 
Hi all,

I found xfs/078 failure with null_blk devices [1]. When I saw the failure for
the first time, it was observed with regular null_blk with 8GB size with 512
bytes sector size. Later on, I was able to recreate with,

 - both zoned and non-zoned
 - both 512 byte sector and 4KB sector
 - device size from 1GB to 8GB

The failure was recreated on QEMU VM test nodes. When I reduce the number of
CPUs assigned to the VM, the test case succeeded. With larger number of CPUs,
the test case failed.

  nproc   |  16  |   8  |   2  |   1
 ---------+------+------+------+------
  xfs/078 | fail | fail | pass | pass

I attach 078.dmesg, 078.full and 078.out.bad for your reference. Actions for fix
will be appreciated. If I can do anything on my testnodes, please let me know.

[1] local.config, command line and outputs

$ cat ./local.config
export TEST_DIR=/var/kts/test
export TEST_DEV="/dev/nullb0"
export KEEP_DMESG=yes
export FSTYP=xfs
export MKFS_OPTIONS=""
export SCRATCH_MNT=/var/kts/scratch
export SCRATCH_DEV="/dev/nullb1"
export FSX_AVOID=-a
$ sudo mkfs.xfs /dev/nullb0
meta-data=/dev/nullb0            isize=512    agcount=4, agsize=524288 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=1, sparse=1, rmapbt=1
         =                       reflink=1    bigtime=1 inobtcount=1 nrext64=1
         =                       exchange=1   metadir=0
data     =                       bsize=4096   blocks=2097152, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1, parent=1
log      =internal log           bsize=4096   blocks=16384, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
         =                       rgcount=0    rgsize=0 extents
         =                       zoned=0      start=0 reserved=0
$ sudo ./check xfs/078
FSTYP         -- xfs (non-debug)
PLATFORM      -- Linux/x86_64 redsun71q 7.1.0-rc1-kts-xfs-g509fdeb3326+ #1 SMP PREEMPT_DYNAMIC Fri May 15 20:16:28 JST 2026
MKFS_OPTIONS  -- -f /dev/nullb1
MOUNT_OPTIONS -- -o context=system_u:object_r:root_t:s0 /dev/nullb1 /var/kts/scratch

xfs/078            - output mismatch (see /home/shin/kts/kernel-test-suite/src/xfstests/results//xfs/078.out.bad)
    --- tests/xfs/078.out       2026-05-18 14:56:44.108307737 +0900
    +++ /home/shin/kts/kernel-test-suite/src/xfstests/results//xfs/078.out.bad  2026-05-22 20:16:11.735184759 +0900
    @@ -188,6 +188,6 @@
     *** mount loop filesystem
     *** grow loop filesystem
     xfs_growfs --BlockSize=4096 --Blocks=268435456
    -data blocks changed from 268435456 to 4194304001
    +data blocks changed from 268435456 to 4194304000
     *** unmount
     *** all done
    ...
    (Run 'diff -u /home/shin/kts/kernel-test-suite/src/xfstests/tests/xfs/078.out /home/shin/kts/kernel-test-suite/src/xfstests/results//xfs/078.out.bad'  to see the entire diff)
Ran: xfs/078
Failures: xfs/078
Failed 1 of 1 tests
078.dmesg (text/plain, 5.7 KB) 
[346638.550194] [  T32208] run fstests xfs/078 at 2026-05-22 20:15:44
[346642.710896] [  T33162] loop0: detected capacity change from 0 to 1344192
[346643.022555] [    T877] I/O error, dev loop0, sector 0 op 0x1:(WRITE) flags 0x800 phys_seg 0 prio class 2
[346643.055173] [  T33175] loop0: detected capacity change from 0 to 2688392
[346643.144484] [  T33177] XFS (loop0): Mounting V5 Filesystem 746f0e35-30af-4136-b531-73e95ad87a3c
[346643.203081] [  T33177] XFS (loop0): Ending clean mount
[346643.338548] [  T33191] XFS (loop0): Unmounting Filesystem 746f0e35-30af-4136-b531-73e95ad87a3c
[346644.011082] [  T33454] loop0: detected capacity change from 0 to 672096
[346644.368598] [  T33466] loop0: detected capacity change from 0 to 2688388
[346644.470308] [  T33468] XFS (loop0): Mounting V5 Filesystem cc06080b-270c-4433-8dad-a753fdbddec6
[346644.525640] [  T33468] XFS (loop0): Ending clean mount
[346644.734001] [  T33482] XFS (loop0): Unmounting Filesystem cc06080b-270c-4433-8dad-a753fdbddec6
[346645.477586] [  T33825] loop0: detected capacity change from 0 to 336048
[346645.739019] [    T325] I/O error, dev loop0, sector 0 op 0x1:(WRITE) flags 0x800 phys_seg 0 prio class 2
[346645.790943] [  T33837] loop0: detected capacity change from 0 to 1344202
[346645.891977] [  T33838] XFS (loop0): Mounting V5 Filesystem b54ad8c9-18b8-42c2-ad83-9be584f2c84a
[346645.931163] [  T33838] XFS (loop0): Ending clean mount
[346646.162087] [  T33852] XFS (loop0): Unmounting Filesystem b54ad8c9-18b8-42c2-ad83-9be584f2c84a
[346646.827080] [  T34195] loop0: detected capacity change from 0 to 2147483648
[346647.612577] [  T34208] loop1: detected capacity change from 0 to 5242880008
[346647.623323] [    T586] I/O error, dev loop0, sector 0 op 0x1:(WRITE) flags 0x800 phys_seg 0 prio class 2
[346647.721646] [  T34210] XFS (loop1): Mounting V5 Filesystem 86a92b03-765d-4e48-8329-4c4e03faf40c
[346647.770548] [  T34210] XFS (loop1): Ending clean mount
[346648.067951] [  T34225] XFS (loop1): Unmounting Filesystem 86a92b03-765d-4e48-8329-4c4e03faf40c
[346648.150529] [      C0] clocksource: Watchdog remote CPU 10 read timed out
[346648.295566] [  T34233] loop0: detected capacity change from 0 to 2147483648
[346649.178443] [  T34246] loop0: detected capacity change from 0 to 7340032008
[346649.272214] [  T34247] XFS (loop0): Mounting V5 Filesystem 386bf672-1e2e-45c2-918d-2bd8e2710011
[346649.341180] [  T34247] XFS (loop0): Ending clean mount
[346649.714697] [  T34261] XFS (loop0): Unmounting Filesystem 386bf672-1e2e-45c2-918d-2bd8e2710011
[346649.949635] [  T34269] loop0: detected capacity change from 0 to 2147483648
[346650.819597] [  T34282] loop1: detected capacity change from 0 to 9437184008
[346650.834446] [   T1008] I/O error, dev loop0, sector 0 op 0x1:(WRITE) flags 0x800 phys_seg 0 prio class 2
[346650.929310] [  T34284] XFS (loop1): Mounting V5 Filesystem ad2552a4-4051-48b3-86af-0b9edfe28bb0
[346650.989257] [  T34284] XFS (loop1): Ending clean mount
[346651.486306] [  T34297] XFS (loop1): Unmounting Filesystem ad2552a4-4051-48b3-86af-0b9edfe28bb0
[346651.647242] [    T586] I/O error, dev loop1, sector 0 op 0x1:(WRITE) flags 0x800 phys_seg 0 prio class 2
[346651.709163] [  T34305] loop0: detected capacity change from 0 to 2147483648
[346652.577727] [  T34318] loop0: detected capacity change from 0 to 11534336008
[346652.677599] [  T34319] XFS (loop0): Mounting V5 Filesystem 766eb1b8-e80f-4ad6-ac35-c98cc6fd4195
[346652.734701] [  T34319] XFS (loop0): Ending clean mount
[346653.283152] [  T34333] XFS (loop0): Unmounting Filesystem 766eb1b8-e80f-4ad6-ac35-c98cc6fd4195
[346653.507118] [  T34341] loop0: detected capacity change from 0 to 2147483648
[346654.329581] [  T34354] loop1: detected capacity change from 0 to 17825792008
[346654.343237] [    T769] I/O error, dev loop0, sector 0 op 0x1:(WRITE) flags 0x800 phys_seg 0 prio class 2
[346654.426162] [  T34356] XFS (loop1): Mounting V5 Filesystem d60fa45a-6533-474d-baad-72b19ae6f2d3
[346654.480317] [  T34356] XFS (loop1): Ending clean mount
[346655.388320] [  T34370] XFS (loop1): Unmounting Filesystem d60fa45a-6533-474d-baad-72b19ae6f2d3
[346655.601878] [  T34378] loop0: detected capacity change from 0 to 2147483648
[346656.427245] [  T34392] loop1: detected capacity change from 0 to 19922944008
[346656.521749] [  T34394] XFS (loop1): Mounting V5 Filesystem c4780098-6c34-4553-ae2c-837f4b6d2c8d
[346656.567558] [  T34394] XFS (loop1): Ending clean mount
[346657.505756] [  T34408] XFS (loop1): Unmounting Filesystem c4780098-6c34-4553-ae2c-837f4b6d2c8d
[346657.727715] [  T34416] loop0: detected capacity change from 0 to 2147483648
[346658.433332] [  T34429] loop1: detected capacity change from 0 to 32505856008
[346658.450508] [    T768] I/O error, dev loop0, sector 0 op 0x1:(WRITE) flags 0x800 phys_seg 0 prio class 2
[346658.530546] [  T34431] XFS (loop1): Mounting V5 Filesystem ebfe392b-8c01-4080-9174-fd1ff3ba0a72
[346658.597583] [  T34431] XFS (loop1): Ending clean mount
[346660.061005] [  T34444] XFS (loop1): Unmounting Filesystem ebfe392b-8c01-4080-9174-fd1ff3ba0a72
[346660.305255] [  T34452] loop0: detected capacity change from 0 to 2147483648
[346661.064456] [  T34465] loop1: detected capacity change from 0 to 33554432008
[346661.077366] [    T325] I/O error, dev loop0, sector 0 op 0x1:(WRITE) flags 0x800 phys_seg 0 prio class 2
[346661.168596] [  T34467] XFS (loop1): Mounting V5 Filesystem ee62fee9-3c2e-4f9f-9f7d-81d108f36128
[346661.222539] [  T34467] XFS (loop1): Ending clean mount
[346662.772152] [  T34482] XFS (loop1): Unmounting Filesystem ee62fee9-3c2e-4f9f-9f7d-81d108f36128
[346665.103767] [  T34652] XFS (nullb0): Unmounting Filesystem 9d6146a4-9265-4658-a98c-d11b0cf45328
[346665.500646] [  T34860] XFS (nullb0): Mounting V5 Filesystem 9d6146a4-9265-4658-a98c-d11b0cf45328
[346665.527151] [  T34860] XFS (nullb0): Ending clean mount
078.full (text/plain, 78 B) 
umount: /var/kts/test/078.mnt: not mounted.
umount: /dev/nullb1: not mounted.
078.out.bad (text/plain, 6.1 KB) 
QA output created by 078
*** create loop mount point

=== GROWFS (from 688226304 to 1376452608, 4096 blocksize)

*** mkfs loop file (size=688226304)
meta-data=DDEV isize=XXX agcount=N, agsize=XXX blks
data     = bsize=XXX blocks=XXX, imaxpct=PCT
         = sunit=XXX swidth=XXX, unwritten=X
naming   =VERN bsize=XXX
log      =LDEV bsize=XXX blocks=XXX
realtime =RDEV extsz=XXX blocks=XXX, rtextents=XXX
*** extend loop file
wrote 4096/4096 bytes at offset 1376452608
*** mount loop filesystem
*** grow loop filesystem
xfs_growfs --BlockSize=4096 --Blocks=168024
data blocks changed from 168024 to 336048
*** unmount
*** check

=== GROWFS (from 344113152 to 1376452608, 2048 blocksize)

*** mkfs loop file (size=344113152)
meta-data=DDEV isize=XXX agcount=N, agsize=XXX blks
data     = bsize=XXX blocks=XXX, imaxpct=PCT
         = sunit=XXX swidth=XXX, unwritten=X
naming   =VERN bsize=XXX
log      =LDEV bsize=XXX blocks=XXX
realtime =RDEV extsz=XXX blocks=XXX, rtextents=XXX
*** extend loop file
wrote 2048/2048 bytes at offset 1376452608
*** mount loop filesystem
*** grow loop filesystem
xfs_growfs --BlockSize=2048 --Blocks=168024
data blocks changed from 168024 to 672096
*** unmount
*** check

=== GROWFS (from 172056576 to 688230400, 1024 blocksize)

*** mkfs loop file (size=172056576)
meta-data=DDEV isize=XXX agcount=N, agsize=XXX blks
data     = bsize=XXX blocks=XXX, imaxpct=PCT
         = sunit=XXX swidth=XXX, unwritten=X
naming   =VERN bsize=XXX
log      =LDEV bsize=XXX blocks=XXX
realtime =RDEV extsz=XXX blocks=XXX, rtextents=XXX
*** extend loop file
wrote 1024/1024 bytes at offset 688230400
*** mount loop filesystem
*** grow loop filesystem
xfs_growfs --BlockSize=1024 --Blocks=168024
data blocks changed from 168024 to 672096
*** unmount
*** check

=== GROWFS (from 1t to 2500g, 4096 blocksize)

*** mkfs loop file (size=1t)
meta-data=DDEV isize=XXX agcount=N, agsize=XXX blks
data     = bsize=XXX blocks=XXX, imaxpct=PCT
         = sunit=XXX swidth=XXX, unwritten=X
naming   =VERN bsize=XXX
log      =LDEV bsize=XXX blocks=XXX
realtime =RDEV extsz=XXX blocks=XXX, rtextents=XXX
*** extend loop file
wrote 4096/4096 bytes at offset 2684354560000
*** mount loop filesystem
*** grow loop filesystem
xfs_growfs --BlockSize=4096 --Blocks=268435456
data blocks changed from 268435456 to 655360001
*** unmount

=== GROWFS (from 1t to 3500g, 4096 blocksize)

*** mkfs loop file (size=1t)
meta-data=DDEV isize=XXX agcount=N, agsize=XXX blks
data     = bsize=XXX blocks=XXX, imaxpct=PCT
         = sunit=XXX swidth=XXX, unwritten=X
naming   =VERN bsize=XXX
log      =LDEV bsize=XXX blocks=XXX
realtime =RDEV extsz=XXX blocks=XXX, rtextents=XXX
*** extend loop file
wrote 4096/4096 bytes at offset 3758096384000
*** mount loop filesystem
*** grow loop filesystem
xfs_growfs --BlockSize=4096 --Blocks=268435456
data blocks changed from 268435456 to 917504001
*** unmount

=== GROWFS (from 1t to 4500g, 4096 blocksize)

*** mkfs loop file (size=1t)
meta-data=DDEV isize=XXX agcount=N, agsize=XXX blks
data     = bsize=XXX blocks=XXX, imaxpct=PCT
         = sunit=XXX swidth=XXX, unwritten=X
naming   =VERN bsize=XXX
log      =LDEV bsize=XXX blocks=XXX
realtime =RDEV extsz=XXX blocks=XXX, rtextents=XXX
*** extend loop file
wrote 4096/4096 bytes at offset 4831838208000
*** mount loop filesystem
*** grow loop filesystem
xfs_growfs --BlockSize=4096 --Blocks=268435456
data blocks changed from 268435456 to 1179648001
*** unmount

=== GROWFS (from 1t to 5500g, 4096 blocksize)

*** mkfs loop file (size=1t)
meta-data=DDEV isize=XXX agcount=N, agsize=XXX blks
data     = bsize=XXX blocks=XXX, imaxpct=PCT
         = sunit=XXX swidth=XXX, unwritten=X
naming   =VERN bsize=XXX
log      =LDEV bsize=XXX blocks=XXX
realtime =RDEV extsz=XXX blocks=XXX, rtextents=XXX
*** extend loop file
wrote 4096/4096 bytes at offset 5905580032000
*** mount loop filesystem
*** grow loop filesystem
xfs_growfs --BlockSize=4096 --Blocks=268435456
data blocks changed from 268435456 to 1441792001
*** unmount

=== GROWFS (from 1t to 8500g, 4096 blocksize)

*** mkfs loop file (size=1t)
meta-data=DDEV isize=XXX agcount=N, agsize=XXX blks
data     = bsize=XXX blocks=XXX, imaxpct=PCT
         = sunit=XXX swidth=XXX, unwritten=X
naming   =VERN bsize=XXX
log      =LDEV bsize=XXX blocks=XXX
realtime =RDEV extsz=XXX blocks=XXX, rtextents=XXX
*** extend loop file
wrote 4096/4096 bytes at offset 9126805504000
*** mount loop filesystem
*** grow loop filesystem
xfs_growfs --BlockSize=4096 --Blocks=268435456
data blocks changed from 268435456 to 2228224001
*** unmount

=== GROWFS (from 1t to 9500g, 4096 blocksize)

*** mkfs loop file (size=1t)
meta-data=DDEV isize=XXX agcount=N, agsize=XXX blks
data     = bsize=XXX blocks=XXX, imaxpct=PCT
         = sunit=XXX swidth=XXX, unwritten=X
naming   =VERN bsize=XXX
log      =LDEV bsize=XXX blocks=XXX
realtime =RDEV extsz=XXX blocks=XXX, rtextents=XXX
*** extend loop file
wrote 4096/4096 bytes at offset 10200547328000
*** mount loop filesystem
*** grow loop filesystem
xfs_growfs --BlockSize=4096 --Blocks=268435456
data blocks changed from 268435456 to 2490368001
*** unmount

=== GROWFS (from 1t to 15500g, 4096 blocksize)

*** mkfs loop file (size=1t)
meta-data=DDEV isize=XXX agcount=N, agsize=XXX blks
data     = bsize=XXX blocks=XXX, imaxpct=PCT
         = sunit=XXX swidth=XXX, unwritten=X
naming   =VERN bsize=XXX
log      =LDEV bsize=XXX blocks=XXX
realtime =RDEV extsz=XXX blocks=XXX, rtextents=XXX
*** extend loop file
wrote 4096/4096 bytes at offset 16642998272000
*** mount loop filesystem
*** grow loop filesystem
xfs_growfs --BlockSize=4096 --Blocks=268435456
data blocks changed from 268435456 to 4063232001
*** unmount

=== GROWFS (from 1t to 16000g, 4096 blocksize)

*** mkfs loop file (size=1t)
meta-data=DDEV isize=XXX agcount=N, agsize=XXX blks
data     = bsize=XXX blocks=XXX, imaxpct=PCT
         = sunit=XXX swidth=XXX, unwritten=X
naming   =VERN bsize=XXX
log      =LDEV bsize=XXX blocks=XXX
realtime =RDEV extsz=XXX blocks=XXX, rtextents=XXX
*** extend loop file
wrote 4096/4096 bytes at offset 17179869184000
*** mount loop filesystem
*** grow loop filesystem
xfs_growfs --BlockSize=4096 --Blocks=268435456
data blocks changed from 268435456 to 4194304000
*** unmount
*** all done
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