syzbot

INFO: task kworker/u8:16:2885 blocked for more than 143 seconds.
      Not tainted 6.10.0-rc2-syzkaller-00366-g771ed66105de #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:16   state:D stack:23816 pid:2885  tgid:2885  ppid:2      flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x1796/0x49d0 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
 exfat_write_inode+0x69/0x120 fs/exfat/inode.c:105
 write_inode fs/fs-writeback.c:1497 [inline]
 __writeback_single_inode+0x6b9/0x10b0 fs/fs-writeback.c:1716
 writeback_sb_inodes+0x99c/0x1380 fs/fs-writeback.c:1947
 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2018
 wb_writeback+0x495/0xd40 fs/fs-writeback.c:2129
 wb_check_background_flush fs/fs-writeback.c:2199 [inline]
 wb_do_writeback fs/fs-writeback.c:2287 [inline]
 wb_workfn+0xc58/0x1090 fs/fs-writeback.c:2314
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3393
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 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: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #0: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #0: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614
5 locks held by kworker/u8:7/2404:
 #0: ffff8880b953e798 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559
 #1: ffff8880b9528948 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x441/0x770 kernel/sched/psi.c:988
 #2: ffff8880b952a718 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x112/0x240 kernel/time/timer.c:1051
 #3: ffffffff949ba608 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_activate+0x16d/0x510 lib/debugobjects.c:708
 #4: ffffffff8e1e3688 (text_mutex){+.+.}-{3:3}, at: arch_jump_label_transform_apply+0x17/0x30 arch/x86/kernel/jump_label.c:145
4 locks held by kworker/u8:16/2885:
 #0: ffff88801b2bd948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline]
 #0: ffff88801b2bd948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312
 #1: ffffc90009f47d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline]
 #1: ffffc90009f47d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312
 #2: ffff88801f8720e0 (&type->s_umount_key#44){.+.+}-{3:3}, at: super_trylock_shared+0x22/0xf0 fs/super.c:562
 #3: ffff88801f8700e0 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_write_inode+0x69/0x120 fs/exfat/inode.c:105
2 locks held by getty/4839:
 #0: ffff88802b0910a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900031332f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2201
3 locks held by syz-executor261/5087:

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

NMI backtrace for cpu 0
CPU: 0 PID: 30 Comm: khungtaskd Not tainted 6.10.0-rc2-syzkaller-00366-g771ed66105de #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xfde/0x1020 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5087 Comm: syz-executor261 Not tainted 6.10.0-rc2-syzkaller-00366-g771ed66105de #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
RIP: 0010:__kasan_check_read+0x0/0x20 mm/kasan/shadow.c:30
Code: 8d 4c 89 fe e8 b1 35 82 09 31 db eb d0 66 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 <f3> 0f 1e fa 89 f6 48 8b 0c 24 31 d2 e9 6f e6 ff ff 66 2e 0f 1f 84
RSP: 0018:ffffc9000353f378 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8fac1ea8
RBP: ffffc9000353f4d0 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff940003ee9e9 R12: 1ffff920006a7e78
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88801d541700
FS:  00005555557ee380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff74f80d0c CR3: 000000002eadc000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 cpumask_test_cpu include/linux/cpumask.h:571 [inline]
 cpu_online include/linux/cpumask.h:1181 [inline]
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0xd4/0x550 kernel/locking/lockdep.c:5725
 fs_reclaim_acquire+0xaf/0x140 mm/page_alloc.c:3818
 might_alloc include/linux/sched/mm.h:334 [inline]
 bdev_getblk+0x3d/0x5a0 fs/buffer.c:1439
 __bread_gfp+0x86/0x400 fs/buffer.c:1497
 sb_bread include/linux/buffer_head.h:347 [inline]
 exfat_get_dentry+0x53b/0x730 fs/exfat/dir.c:691
 exfat_readdir fs/exfat/dir.c:121 [inline]
 exfat_iterate+0xbd7/0x33e0 fs/exfat/dir.c:261
 wrap_directory_iterator+0x94/0xe0 fs/readdir.c:67
 iterate_dir+0x65e/0x820 fs/readdir.c:110
 __do_sys_getdents64 fs/readdir.c:409 [inline]
 __se_sys_getdents64+0x20d/0x4f0 fs/readdir.c:394
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff405b880a3
Code: c1 66 0f 1f 44 00 00 48 83 c4 08 48 89 ef 5b 5d e9 82 48 fb ff 66 90 b8 ff ff ff 7f 48 39 c2 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 c7 c2 b8 ff ff ff f7 d8
RSP: 002b:00007ffc3a6cebd8 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00005555557f7730 RCX: 00007ff405b880a3
RDX: 0000000000008000 RSI: 00005555557f7730 RDI: 0000000000000004
RBP: 00005555557f7704 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000001000 R11: 0000000000000293 R12: ffffffffffffffb8
R13: 0000000000000010 R14: 00005555557f7700 R15: 00007ffc3a6d0e50
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.283 msecs