LinuxLists.cc - [PATCH v2 2/2] ext4: set 256 blocks in a block group then apply io pressure

2022-07-08 11:13:27

Subject: [PATCH v2 2/2] ext4: set 256 blocks in a block group then apply io pressure

Set 256 blocks in a block group, then inject I/O pressure, it will
trigger off kernel BUG in ext4_mb_mark_diskspace_used.

Regression test for commit a08f789d2ab5 ext4: fix bug_on
ext4_mb_use_inode_pa.

Signed-off-by: Sun Ke <[email protected]>
---
tests/ext4/058 | 33 +++++++++++++++++++++++++++++++++
tests/ext4/058.out | 2 ++
2 files changed, 35 insertions(+)
create mode 100755 tests/ext4/058
create mode 100644 tests/ext4/058.out

diff --git a/tests/ext4/058 b/tests/ext4/058
new file mode 100755
index 00000000..b718c1ac
--- /dev/null
+++ b/tests/ext4/058
@@ -0,0 +1,33 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2022 HUAWEI. All Rights Reserved.
+#
+# FS QA Test 058
+#
+# Set 256 blocks in a block group, then inject I/O pressure,
+# it will trigger off kernel BUG in ext4_mb_mark_diskspace_used
+#
+# Regression test for commit
+# a08f789d2ab5 ext4: fix bug_on ext4_mb_use_inode_pa
+#
+. ./common/preamble
+_begin_fstest auto
+
+# real QA test starts here
+
+_supported_fs ext4
+_fixed_by_kernel_commit a08f789d2ab5 \
+ "ext4: fix bug_on ext4_mb_use_inode_pa"
+_require_scratch
+
+# set 256 blocks in a block group
+_scratch_mkfs -g 256 >>$seqres.full 2>&1 || _fail "mkfs failed"
+_scratch_mount
+
+$FSSTRESS_PROG -d $SCRATCH_MNT/stress -n 1000 >> $seqres.full
+
+echo "Silence is golden"
+
+# success, all done
+status=0
+exit
diff --git a/tests/ext4/058.out b/tests/ext4/058.out
new file mode 100644
index 00000000..fb5ca60b
--- /dev/null
+++ b/tests/ext4/058.out
@@ -0,0 +1,2 @@
+QA output created by 058
+Silence is golden
--
2.13.6

2022-07-08 15:26:47

by Zorro Lang

[permalink] [raw]

Subject: Re: [PATCH v2 2/2] ext4: set 256 blocks in a block group then apply io pressure

On Fri, Jul 08, 2022 at 07:21:55PM +0800, Sun Ke wrote:
> Set 256 blocks in a block group, then inject I/O pressure, it will
> trigger off kernel BUG in ext4_mb_mark_diskspace_used.
>
> Regression test for commit a08f789d2ab5 ext4: fix bug_on
> ext4_mb_use_inode_pa.
>
> Signed-off-by: Sun Ke <[email protected]>
> ---
> tests/ext4/058 | 33 +++++++++++++++++++++++++++++++++
> tests/ext4/058.out | 2 ++
> 2 files changed, 35 insertions(+)
> create mode 100755 tests/ext4/058
> create mode 100644 tests/ext4/058.out
>
> diff --git a/tests/ext4/058 b/tests/ext4/058
> new file mode 100755
> index 00000000..b718c1ac
> --- /dev/null
> +++ b/tests/ext4/058
> @@ -0,0 +1,33 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2022 HUAWEI. All Rights Reserved.
> +#
> +# FS QA Test 058
> +#
> +# Set 256 blocks in a block group, then inject I/O pressure,
> +# it will trigger off kernel BUG in ext4_mb_mark_diskspace_used
> +#
> +# Regression test for commit
> +# a08f789d2ab5 ext4: fix bug_on ext4_mb_use_inode_pa
> +#
> +. ./common/preamble
> +_begin_fstest auto

quick ?

> +
> +# real QA test starts here
> +
> +_supported_fs ext4
> +_fixed_by_kernel_commit a08f789d2ab5 \
> + "ext4: fix bug_on ext4_mb_use_inode_pa"
> +_require_scratch
> +
> +# set 256 blocks in a block group
> +_scratch_mkfs -g 256 >>$seqres.full 2>&1 || _fail "mkfs failed"
> +_scratch_mount
> +
> +$FSSTRESS_PROG -d $SCRATCH_MNT/stress -n 1000 >> $seqres.full

Use "2>&1", if you'd like to avoid some fsstress error output break golden image.

BTW, just for make, are you sure this can reproduce that bug? Due to that fix
commit said:
...
we can easily reproduce this problem with the following commands:
`fallocate -l100M disk`
`mkfs.ext4 -b 1024 -g 256 disk`
`mount disk /mnt`
`fsstress -d /mnt -l 0 -n 1000 -p 1`
...

It uses "-l 0" to loop run fsstress until hit the bug. You removed the '-l 0',
so are you sure one round `fsstress -n 1000` is enough to reproduce this bug
stably?

Thanks,
Zorro

> +
> +echo "Silence is golden"
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/ext4/058.out b/tests/ext4/058.out
> new file mode 100644
> index 00000000..fb5ca60b
> --- /dev/null
> +++ b/tests/ext4/058.out
> @@ -0,0 +1,2 @@
> +QA output created by 058
> +Silence is golden
> --
> 2.13.6
>

2022-07-11 07:28:09

by Sun Ke

[permalink] [raw]

Subject: Re: [PATCH v2 2/2] ext4: set 256 blocks in a block group then apply io pressure

?? 2022/7/8 23:20, Zorro Lang д??:
> On Fri, Jul 08, 2022 at 07:21:55PM +0800, Sun Ke wrote:
>> Set 256 blocks in a block group, then inject I/O pressure, it will
>> trigger off kernel BUG in ext4_mb_mark_diskspace_used.
>>
>> Regression test for commit a08f789d2ab5 ext4: fix bug_on
>> ext4_mb_use_inode_pa.
>>
>> Signed-off-by: Sun Ke <[email protected]>
>> ---
>> tests/ext4/058 | 33 +++++++++++++++++++++++++++++++++
>> tests/ext4/058.out | 2 ++
>> 2 files changed, 35 insertions(+)
>> create mode 100755 tests/ext4/058
>> create mode 100644 tests/ext4/058.out
>>
>> diff --git a/tests/ext4/058 b/tests/ext4/058
>> new file mode 100755
>> index 00000000..b718c1ac
>> --- /dev/null
>> +++ b/tests/ext4/058
>> @@ -0,0 +1,33 @@
>> +#! /bin/bash
>> +# SPDX-License-Identifier: GPL-2.0
>> +# Copyright (c) 2022 HUAWEI. All Rights Reserved.
>> +#
>> +# FS QA Test 058
>> +#
>> +# Set 256 blocks in a block group, then inject I/O pressure,
>> +# it will trigger off kernel BUG in ext4_mb_mark_diskspace_used
>> +#
>> +# Regression test for commit
>> +# a08f789d2ab5 ext4: fix bug_on ext4_mb_use_inode_pa
>> +#
>> +. ./common/preamble
>> +_begin_fstest auto
>
> quick ?
>
>> +
>> +# real QA test starts here
>> +
>> +_supported_fs ext4
>> +_fixed_by_kernel_commit a08f789d2ab5 \
>> + "ext4: fix bug_on ext4_mb_use_inode_pa"
>> +_require_scratch
>> +
>> +# set 256 blocks in a block group
>> +_scratch_mkfs -g 256 >>$seqres.full 2>&1 || _fail "mkfs failed"
>> +_scratch_mount
>> +
>> +$FSSTRESS_PROG -d $SCRATCH_MNT/stress -n 1000 >> $seqres.full
>
> Use "2>&1", if you'd like to avoid some fsstress error output break golden image.
>
> BTW, just for make, are you sure this can reproduce that bug? Due to that fix
> commit said:
> ...
> we can easily reproduce this problem with the following commands:
> `fallocate -l100M disk`
> `mkfs.ext4 -b 1024 -g 256 disk`
> `mount disk /mnt`
> `fsstress -d /mnt -l 0 -n 1000 -p 1`
> ...
>
> It uses "-l 0" to loop run fsstress until hit the bug. You removed the '-l 0',
> so are you sure one round `fsstress -n 1000` is enough to reproduce this bug
> stably?
>
> Thanks,
> Zorro
It is enough ro reproduce this bug, it takes about 1 second:

[ 120.723374] run fstests ext4/058 at 2022-07-11 11:42:51
[[0;32m OK [0m] Started /usr/bin/bash -c test -w /p??_score_adj; exec
./tests/ext4/058.
[ 121.841680] ------------[ cut here ]------------
[ 121.847476] kernel BUG at fs/ext4/mballoc.c:3786!
[ 121.848522] invalid opcode: 0000 [#1] PREEMPT SMP
[ 121.849520] CPU: 1 PID: 995 Comm: fsstress Not tainted
5.18.0-rc3-00087-g98d40e76652e #3
[ 121.851182] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.10.2-1ubuntu1 04/01/2014
[ 121.853023] RIP: 0010:ext4_mb_mark_diskspace_used+0x3d6/0x750
[ 121.854222] Code: 05 3e b3 26 0c 01 b8 fb ff ff ff e9 e7 fc ff ff 48
83 05 dc b2 26 0c 01 0f 0b 48 83 05 da b2 26 0c 01 48 83 05 da b2 26 0c
01 <0f> 0b 48 83 05 e0 b2 26 0c 01 48 83 05 e8 b2 26 0c 01 e9 db fc ff
[ 121.858035] RSP: 0018:ffffc90001857978 EFLAGS: 00010202
[ 121.859119] RAX: 00000000ffffffcd RBX: ffff88810f247000 RCX:
ffffc90001857abc
[ 121.860584] RDX: 0000000000000016 RSI: ffff88810f2460a8 RDI:
ffff88810f247000
[ 121.862056] RBP: ffffc90001857ae0 R08: ffff88810f24daf8 R09:
00000000ffffffcd
[ 121.863522] R10: 0000000000000000 R11: 0000000000000001 R12:
ffffc90001857be8
[ 121.864994] R13: 0000000000000016 R14: ffff8881024a5800 R15:
ffff88810f247000
[ 121.866461] FS: 00007fdc292d4700(0000) GS:ffff88813bc80000(0000)
knlGS:0000000000000000
[ 121.868118] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 121.869309] CR2: 00007fdc292eb000 CR3: 000000010a161000 CR4:
00000000000006e0
[ 121.870776] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[ 121.872241] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
0000000000000400
[ 121.873711] Call Trace:
[ 121.874247] <TASK>
[ 121.874707] ext4_mb_new_blocks+0x74a/0x1f20
[ 121.875599] ? ext4_find_extent+0x61d/0x900
[ 121.876472] ext4_ext_map_blocks+0xbea/0x1d80
[ 121.877386] ext4_map_blocks+0x15d/0xa20
[ 121.878204] ext4_iomap_begin+0x18c/0x3d0
[ 121.879041] iomap_iter+0x1c7/0x5b0
[ 121.879777] __iomap_dio_rw+0x293/0xb40
[ 121.880583] iomap_dio_rw+0x12/0x70
[ 121.881320] ext4_file_write_iter+0x86b/0xcd0
[ 121.882228] new_sync_write+0x140/0x1e0
[ 121.883034] vfs_write+0x312/0x4c0
[ 121.883751] ksys_write+0x73/0x160
[ 121.884465] __x64_sys_write+0x1e/0x30
[ 121.885257] do_syscall_64+0x35/0x80
[ 121.886014] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 121.887066] RIP: 0033:0x7fdc28811280

Thanks,
Sun Ke

>
>> +
>> +echo "Silence is golden"
>> +
>> +# success, all done
>> +status=0
>> +exit
>> diff --git a/tests/ext4/058.out b/tests/ext4/058.out
>> new file mode 100644
>> index 00000000..fb5ca60b
>> --- /dev/null
>> +++ b/tests/ext4/058.out
>> @@ -0,0 +1,2 @@
>> +QA output created by 058
>> +Silence is golden
>> --
>> 2.13.6
>>
>
>
> .
>