Re: [syzbot] [bcachefs?] INFO: task hung in bch2_fs_read_only_work (2)

[Alan Huang <mmpgouride@gmail.com>]

On Apr 7, 2025, at 01:51, syzbot <syzbot+674ccd0645d379ed5f80@syzkaller.appspotmail.com> wrote:
> 
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    a2392f333575 drm/panthor: Clean up FW version information ..
> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
> console output: https://syzkaller.appspot.com/x/log.txt?x=17077c3f980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=8cceedf2e27e877d
> dashboard link: https://syzkaller.appspot.com/bug?extid=674ccd0645d379ed5f80
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> userspace arch: arm64
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10fd894c580000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/7df8ceab3279/disk-a2392f33.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/42c5af403371/vmlinux-a2392f33.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/73599b849e20/Image-a2392f33.gz.xz
> mounted in repro: https://storage.googleapis.com/syzbot-assets/fd7871ac7900/mount_0.gz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+674ccd0645d379ed5f80@syzkaller.appspotmail.com
> 
> INFO: task kworker/1:4:6586 blocked for more than 143 seconds.
>      Not tainted 6.14.0-rc7-syzkaller-ga2392f333575 #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:kworker/1:4     state:D stack:0     pid:6586  tgid:6586  ppid:2      task_flags:0x4208060 flags:0x00000008
> Workqueue: events_long bch2_fs_read_only_work
> Call trace:
> __switch_to+0x414/0x788 arch/arm64/kernel/process.c:701 (T)
> context_switch kernel/sched/core.c:5378 [inline]
> __schedule+0x1360/0x257c kernel/sched/core.c:6765
> __schedule_loop kernel/sched/core.c:6842 [inline]
> schedule+0xbc/0x238 kernel/sched/core.c:6857
> schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6914
> rwsem_down_write_slowpath+0xd10/0x14c8 kernel/locking/rwsem.c:1176
> __down_write_common kernel/locking/rwsem.c:1304 [inline]
> __down_write kernel/locking/rwsem.c:1313 [inline]
> down_write+0xb4/0xc0 kernel/locking/rwsem.c:1578

state_lock

> bch2_fs_read_only_work+0x28/0x48 fs/bcachefs/super.c:393
> process_one_work+0x810/0x1638 kernel/workqueue.c:3238
> process_scheduled_works kernel/workqueue.c:3319 [inline]
> worker_thread+0x97c/0xeec kernel/workqueue.c:3400
> kthread+0x65c/0x7b0 kernel/kthread.c:464
> ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862
> INFO: task syz.0.388:10111 blocked for more than 143 seconds.
>      Not tainted 6.14.0-rc7-syzkaller-ga2392f333575 #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:syz.0.388       state:D stack:0     pid:10111 tgid:10110 ppid:6583   task_flags:0x400140 flags:0x0000000d
> Call trace:
> __switch_to+0x414/0x788 arch/arm64/kernel/process.c:701 (T)
> context_switch kernel/sched/core.c:5378 [inline]
> __schedule+0x1360/0x257c kernel/sched/core.c:6765
> __schedule_loop kernel/sched/core.c:6842 [inline]
> schedule+0xbc/0x238 kernel/sched/core.c:6857
> __closure_sync+0x198/0x29c lib/closure.c:146
> closure_sync include/linux/closure.h:195 [inline]

sync with state_lock held
 
> bch2_journal_flush_pins+0x1e0/0x348 fs/bcachefs/journal_reclaim.c:911
> bch2_journal_flush_all_pins fs/bcachefs/journal_reclaim.h:76 [inline]
> bch2_journal_replay+0x1c28/0x1f64 fs/bcachefs/recovery.c:442
> bch2_run_recovery_pass+0xe4/0x1d4 fs/bcachefs/recovery_passes.c:226
> bch2_run_recovery_passes+0x260/0x92c fs/bcachefs/recovery_passes.c:291
> bch2_fs_recovery+0x20e0/0x32ec fs/bcachefs/recovery.c:936
> bch2_fs_start+0x32c/0x570 fs/bcachefs/super.c:1041
> bch2_fs_get_tree+0xa50/0x11d4 fs/bcachefs/fs.c:2203
> vfs_get_tree+0x90/0x28c fs/super.c:1814
> do_new_mount+0x278/0x900 fs/namespace.c:3560
> path_mount+0x590/0xe04 fs/namespace.c:3887
> do_mount fs/namespace.c:3900 [inline]
> __do_sys_mount fs/namespace.c:4111 [inline]
> __se_sys_mount fs/namespace.c:4088 [inline]
> __arm64_sys_mount+0x4f4/0x5d0 fs/namespace.c:4088
> __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
> invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
> el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
> do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
> el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744
> el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
> el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
> 
> Showing all locks held in the system:
> 1 lock held by khungtaskd/32:
> #0: ffff80008ff22620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:336
> 1 lock held by udevd/6081:
> 2 locks held by getty/6220:
> #0: ffff0000d74fa0a0 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
> #1: ffff80009bf4e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41c/0x1228 drivers/tty/n_tty.c:2211
> 3 locks held by kworker/1:4/6586:
> #0: ffff0000c0029548 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x674/0x1638 kernel/workqueue.c:3212
> #1: ffff80009f6b7ba0 ((work_completion)(&c->read_only_work)){+.+.}-{0:0}, at: process_one_work+0x708/0x1638 kernel/workqueue.c:3212
> #2: ffff0000e7500278 (&c->state_lock){+.+.}-{4:4}, at: bch2_fs_read_only_work+0x28/0x48 fs/bcachefs/super.c:393
> 1 lock held by syz.0.388/10111:
> #0: ffff0000e7500278 (&c->state_lock){+.+.}-{4:4}, at: bch2_fs_start+0x50/0x570 fs/bcachefs/super.c:1010
> 2 locks held by kworker/1:5/11232:
> #0: ffff0001b3772798 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:598 [inline]
> #0: ffff0001b3772798 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock kernel/sched/sched.h:1521 [inline]
> #0: ffff0001b3772798 (&rq->__lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1852 [inline]
> #0: ffff0001b3772798 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0x2e0/0x257c kernel/sched/core.c:6688
> #1: ffff0001b375d408 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x394/0x5e8 kernel/sched/psi.c:987
> 2 locks held by syz.3.1147/16990:
> 2 locks held by syz.4.1148/16993:
> #0: ffff0000fc500920 (&c->sb_lock){+.+.}-{4:4}, at: bch2_fs_alloc fs/bcachefs/super.c:833 [inline]
> #0: ffff0000fc500920 (&c->sb_lock){+.+.}-{4:4}, at: bch2_fs_open+0x1238/0x299c fs/bcachefs/super.c:2065
> #1: ffff0000fc5049b0 (&c->mark_lock){++++}-{0:0}, at: bch2_sb_replicas_to_cpu_replicas+0x198/0x290 fs/bcachefs/replicas.c:600
> 3 locks held by syz.5.1149/17000:
> 2 locks held by syz.2.1150/17009:
> 
> =============================================
> 
> 
> 
> ---
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