Message-ID: <CA+G9fYsyYQ3ZL4xaSg1-Tt5Evto7Zd+hgNWZEa9cQLbahA1+xg@mail.gmail.com>
Date: Thu, 26 Jun 2025 18:01:16 +0530
From: Naresh Kamboju <naresh.kamboju@...aro.org>
To: linux-ext4 <linux-ext4@...r.kernel.org>, linux-fsdevel@...r.kernel.org, 
	open list <linux-kernel@...r.kernel.org>, lkft-triage@...ts.linaro.org, 
	Linux Regressions <regressions@...ts.linux.dev>, LTP List <ltp@...ts.linux.it>
Cc: "Theodore Ts'o" <tytso@....edu>, Jan Kara <jack@...e.cz>, 
	Anders Roxell <anders.roxell@...aro.org>, Dan Carpenter <dan.carpenter@...aro.org>, 
	Arnd Bergmann <arnd@...db.de>
Subject: next-20250626: WARNING fs jbd2 transaction.c start_this_handle with ARM64_64K_PAGES

Regressions noticed on arm64 devices while running LTP syscalls mmap16
test case on the Linux next-20250616..next-20250626 with the extra build
config fragment CONFIG_ARM64_64K_PAGES=y the kernel warning noticed.

Not reproducible with 4K page size.

Test environments:
- Dragonboard-410c
- Juno-r2
- rk3399-rock-pi-4b
- qemu-arm64

Regression Analysis:
- New regression? Yes
- Reproducibility? Yes

Test regression: next-20250626 LTP mmap16 WARNING fs jbd2
transaction.c start_this_handle

Reported-by: Linux Kernel Functional Testing <lkft@...aro.org>

## Test log
<6>[   89.498969] loop0: detected capacity change from 0 to 614400
<3>[   89.609561] operation not supported error, dev loop0, sector
20352 op 0x9:(WRITE_ZEROES) flags 0x20000800 phys_seg 0 prio class 0
<6>[   89.707795] EXT4-fs (loop0): mounted filesystem
6786a191-5e0d-472b-8bce-4714e1a4fb44 r/w with ordered data mode. Quota
mode: none.
<3>[   90.023985] JBD2: kworker/u8:2 wants too many credits
credits:416 rsv_credits:21 max:334
<4>[   90.024973] ------------[ cut here ]------------
<4>[ 90.025062] WARNING: fs/jbd2/transaction.c:334 at
start_this_handle+0x4c0/0x4e0, CPU#0: 2/42
<4>[   90.026661] Modules linked in: btrfs blake2b_generic xor
xor_neon raid6_pq zstd_compress sm3_ce sha3_ce fuse drm backlight
ip_tables x_tables
<4>[   90.027952] CPU: 0 UID: 0 PID: 42 Comm: kworker/u8:2 Not tainted
6.16.0-rc3-next-20250626 #1 PREEMPT
<4>[   90.029043] Hardware name: linux,dummy-virt (DT)
<4>[   90.029524] Workqueue: writeback wb_workfn (flush-7:0)
<4>[   90.030050] pstate: 63402009 (nZCv daif +PAN -UAO +TCO +DIT
-SSBS BTYPE=--)
<4>[ 90.030311] pc : start_this_handle (fs/jbd2/transaction.c:334
(discriminator 1))
<4>[ 90.030481] lr : start_this_handle (fs/jbd2/transaction.c:334
(discriminator 1))
<4>[   90.030656] sp : ffffc000805cb650
<4>[   90.030785] x29: ffffc000805cb690 x28: fff00000dd1f5000 x27:
ffffde2ec0272000
<4>[   90.031097] x26: 00000000000001a0 x25: 0000000000000015 x24:
0000000000000002
<4>[   90.031360] x23: 0000000000000015 x22: 0000000000000c40 x21:
0000000000000008
<4>[   90.031618] x20: fff00000c231da78 x19: fff00000c231da78 x18:
0000000000000000
<4>[   90.031875] x17: 0000000000000000 x16: 0000000000000000 x15:
0000000000000000
<4>[   90.032859] x14: 0000000000000000 x13: 00000000ffffffff x12:
0000000000000000
<4>[   90.033225] x11: 0000000000000000 x10: ffffde2ebfba8bd0 x9 :
ffffde2ebd34e944
<4>[   90.033607] x8 : ffffc000805cb278 x7 : 0000000000000000 x6 :
0000000000000001
<4>[   90.033971] x5 : ffffde2ebfb29000 x4 : ffffde2ebfb293d0 x3 :
0000000000000000
<4>[   90.034294] x2 : 0000000000000000 x1 : fff00000c04dc080 x0 :
000000000000004c
<4>[   90.034772] Call trace:
<4>[ 90.035068] start_this_handle (fs/jbd2/transaction.c:334
(discriminator 1)) (P)
<4>[ 90.035366] jbd2__journal_start (fs/jbd2/transaction.c:501)
<4>[ 90.035586] __ext4_journal_start_sb (fs/ext4/ext4_jbd2.c:117)
<4>[ 90.035807] ext4_do_writepages (fs/ext4/ext4_jbd2.h:242
fs/ext4/inode.c:2846)
<4>[ 90.036004] ext4_writepages (fs/ext4/inode.c:2953)
<4>[ 90.036233] do_writepages (mm/page-writeback.c:2636)
<4>[ 90.036406] __writeback_single_inode (fs/fs-writeback.c:1680)
<4>[ 90.036616] writeback_sb_inodes (fs/fs-writeback.c:1978)
<4>[ 90.036891] wb_writeback (fs/fs-writeback.c:2156)
<4>[ 90.037122] wb_workfn (fs/fs-writeback.c:2303 (discriminator 1)
fs/fs-writeback.c:2343 (discriminator 1))
<4>[ 90.037318] process_one_work (kernel/workqueue.c:3244)
<4>[ 90.037517] worker_thread (kernel/workqueue.c:3316 (discriminator
2) kernel/workqueue.c:3403 (discriminator 2))
<4>[ 90.037752] kthread (kernel/kthread.c:463)
<4>[ 90.037903] ret_from_fork (arch/arm64/kernel/entry.S:863)
<4>[   90.038217] ---[ end trace 0000000000000000 ]---
<2>[   90.039950] EXT4-fs (loop0): ext4_do_writepages: jbd2_start:
9223372036854775807 pages, ino 14; err -28
<3>[   90.040291] JBD2: kworker/u8:2 wants too many credits
credits:416 rsv_credits:21 max:334
<4>[   90.040374] ------------[ cut here ]------------
<4>[ 90.040386] WARNING: fs/jbd2/transaction.c:334 at
start_this_handle+0x4c0/0x4e0, CPU#1: 2/42


## Source
* Kernel version: 6.16.0-rc3-next-20250626
* Git tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next.git
* Git sha: ecb259c4f70dd5c83907809f45bf4dc6869961d7
* Git describe: 6.16.0-rc3-next-20250626
* Project details:
https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20250626/
* Architectures: arm64
* Toolchains: gcc-13
* Kconfigs: gcc-13-lkftconfig-64k_page_size

## Build arm64
* Test log: https://qa-reports.linaro.org/api/testruns/28894530/log_file/
* Test LAVA log 1:
https://lkft.validation.linaro.org/scheduler/job/8331353#L6841
* Test LAVA log 2:
https://lkft.validation.linaro.org/scheduler/job/8331352#L8854
* Test details:
https://regressions.linaro.org/lkft/linux-next-master/next-20250626/log-parser-test/exception-warning-fsjbd2transaction-at-start_this_handle/
* Build link: https://storage.tuxsuite.com/public/linaro/lkft/builds/2z2V7LhiJecGzINkU7ObVQTwoR1/
* Kernel config:
https://storage.tuxsuite.com/public/linaro/lkft/builds/2z2V7LhiJecGzINkU7ObVQTwoR1/config

--
Linaro LKFT
https://lkft.linaro.org

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