Re: [syzbot] [ext4?] INFO: task hung in do_get_write_access (3)

From: syzbot
Date: Sun Feb 02 2025 - 13:31:31 EST

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syzbot has found a reproducer for the following issue on:

HEAD commit: 69e858e0b8b2 Merge tag 'uml-for-linus-6.14-rc1' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=132935f8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=98d83cc1742b7377
dashboard link: https://syzkaller.appspot.com/bug?extid=e7c786ece54bad9d1e43
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10809724580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=132f03df980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3d07b0558b0e/disk-69e858e0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e5e2250eb3b1/vmlinux-69e858e0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3e676d17effc/bzImage-69e858e0.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e7c786ece54bad9d1e43@xxxxxxxxxxxxxxxxxxxxxxxxx

INFO: task kworker/u8:5:76 blocked for more than 143 seconds.
Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:5 state:D stack:23760 pid:76 tgid:76 ppid:2 task_flags:0x4248060 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5377 [inline]
__schedule+0xf43/0x5890 kernel/sched/core.c:6764
__schedule_loop kernel/sched/core.c:6841 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6856
io_schedule+0xbf/0x130 kernel/sched/core.c:7689
bit_wait_io+0x15/0xe0 kernel/sched/wait_bit.c:247
__wait_on_bit+0x62/0x180 kernel/sched/wait_bit.c:49
out_of_line_wait_on_bit+0xda/0x110 kernel/sched/wait_bit.c:64
wait_on_bit_io include/linux/wait_bit.h:105 [inline]
do_get_write_access+0x933/0x1270 fs/jbd2/transaction.c:1096
jbd2_journal_get_write_access+0x1d6/0x280 fs/jbd2/transaction.c:1245
__ext4_journal_get_write_access+0x6a/0x340 fs/ext4/ext4_jbd2.c:239
ext4_reserve_inode_write+0x13b/0x270 fs/ext4/inode.c:5831
__ext4_mark_inode_dirty+0x1ab/0x860 fs/ext4/inode.c:6005
__ext4_ext_dirty+0x1a8/0x220 fs/ext4/extents.c:207
ext4_ext_insert_extent+0x12c7/0x3e70 fs/ext4/extents.c:2190
ext4_ext_map_blocks+0x2044/0x5ab0 fs/ext4/extents.c:4400
ext4_map_create_blocks fs/ext4/inode.c:516 [inline]
ext4_map_blocks+0x457/0x1370 fs/ext4/inode.c:702
mpage_map_one_extent fs/ext4/inode.c:2219 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2272 [inline]
ext4_do_writepages+0x198d/0x32d0 fs/ext4/inode.c:2735
ext4_writepages+0x303/0x730 fs/ext4/inode.c:2824
do_writepages+0x1b3/0x820 mm/page-writeback.c:2687
__writeback_single_inode+0x166/0xfa0 fs/fs-writeback.c:1680
writeback_sb_inodes+0x606/0xfa0 fs/fs-writeback.c:1976
__writeback_inodes_wb+0xff/0x2e0 fs/fs-writeback.c:2047
wb_writeback+0x803/0xb80 fs/fs-writeback.c:2158
wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
wb_do_writeback fs/fs-writeback.c:2315 [inline]
wb_workfn+0x8c0/0xbc0 fs/fs-writeback.c:2343
process_one_work+0x958/0x1b30 kernel/workqueue.c:3236
process_scheduled_works kernel/workqueue.c:3317 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
kthread+0x3af/0x750 kernel/kthread.c:464
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
INFO: task jbd2/sda1-8:5171 blocked for more than 144 seconds.
Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:jbd2/sda1-8 state:D stack:26432 pid:5171 tgid:5171 ppid:2 task_flags:0x240040 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5377 [inline]
__schedule+0xf43/0x5890 kernel/sched/core.c:6764
__schedule_loop kernel/sched/core.c:6841 [inline]
schedule+0xe7/0x350 kernel/sched/core.c:6856
io_schedule+0xbf/0x130 kernel/sched/core.c:7689
bit_wait_io+0x15/0xe0 kernel/sched/wait_bit.c:247
__wait_on_bit+0x62/0x180 kernel/sched/wait_bit.c:49
out_of_line_wait_on_bit+0xda/0x110 kernel/sched/wait_bit.c:64
wait_on_bit_io include/linux/wait_bit.h:105 [inline]
__wait_on_buffer+0x64/0x70 fs/buffer.c:123
wait_on_buffer include/linux/buffer_head.h:414 [inline]
jbd2_journal_commit_transaction+0x3823/0x6760 fs/jbd2/commit.c:810
kjournald2+0x1f8/0x760 fs/jbd2/journal.c:201
kthread+0x3af/0x750 kernel/kthread.c:464
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8e1bc080 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
#0: ffffffff8e1bc080 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8e1bc080 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6746
6 locks held by kworker/u8:5/76:
#0: ffff88801eac1148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x12cd/0x1b30 kernel/workqueue.c:3211
#1: ffffc9000216fd18 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3212
#2: ffff88814e6840e0 (&type->s_umount_key#31){++++}-{4:4}, at: super_trylock_shared+0x1e/0xf0 fs/super.c:562
#3: ffff88814e686b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x1b3/0x820 mm/page-writeback.c:2687
#4: ffff88814e690950 (jbd2_handle){.+.+}-{0:0}, at: start_this_handle+0xf6c/0x1430 fs/jbd2/transaction.c:448
#5: ffff888053bfef80 (&ei->i_data_sem){++++}-{4:4}, at: ext4_map_blocks+0x352/0x1370 fs/ext4/inode.c:701
2 locks held by getty/5595:
#0: ffff8880351f20a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211
2 locks held by syz-executor350/13863:
#0: ffff8880b873ed18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:598
#1: ffff8880b8728a88 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x203/0x8e0 kernel/sched/psi.c:975

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline]
watchdog+0xf62/0x12b0 kernel/hung_task.c:399
kthread+0x3af/0x750 kernel/kthread.c:464
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 13875 Comm: syz-executor350 Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:file_set_fsnotify_mode+0xe/0x5d0 fs/notify/fsnotify.c:652
Code: 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 41 57 41 56 41 55 41 54 55 53 <48> 89 fb 48 83 ec 10 e8 76 b6 76 ff 48 8d bb 88 00 00 00 48 b8 00
RSP: 0018:ffffc900032e79c8 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff88802fc64c40 RCX: ffffffff822b6e68
RDX: ffff888021b99e00 RSI: ffffffff822b6e76 RDI: ffff88802fc64c40
RBP: ffff888077665038 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88802fc64c88
R13: ffff88802fc64cc8 R14: 0000000000000000 R15: ffff88802fc64c90
FS: 0000555583826380(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6cf9a1a01d CR3: 000000002a1c8000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<TASK>
do_dentry_open+0x59e/0x1c40 fs/open.c:941
vfs_open+0x82/0x3f0 fs/open.c:1085
do_open fs/namei.c:3830 [inline]
path_openat+0x1e88/0x2d80 fs/namei.c:3989
do_filp_open+0x20c/0x470 fs/namei.c:4016
do_sys_openat2+0x17a/0x1e0 fs/open.c:1427
do_sys_open fs/open.c:1442 [inline]
__do_sys_openat fs/open.c:1458 [inline]
__se_sys_openat fs/open.c:1453 [inline]
__x64_sys_openat+0x175/0x210 fs/open.c:1453
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6cf99d0ae1
Code: 75 57 89 f0 25 00 00 41 00 3d 00 00 41 00 74 49 80 3d 8a 85 07 00 00 74 6d 89 da 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 93 00 00 00 48 8b 54 24 28 64 48 2b 14 25
RSP: 002b:00007ffd1d04c410 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000080001 RCX: 00007f6cf99d0ae1
RDX: 0000000000080001 RSI: 00007f6cf9a1a022 RDI: 00000000ffffff9c
RBP: 00007f6cf9a1a022 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffd1d04c4b0
R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001
</TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.450 msecs

---
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#syz test: git://repo/address.git branch-or-commit-hash
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Next message: Kaustabh Chakraborty: "[PATCH 00/33] Add support for the Exynos7870 SoC, along with three devices"
Previous message: Jiasheng Jiang: "[PATCH] regmap-irq: Add missing kfree()"
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