INFO: task kworker/u4:2:31 blocked for more than 143 seconds. Not tainted 6.16.0-rc3-syzkaller-g78f4e737a53e #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:2 state:D stack:19224 pid:31 tgid:31 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: events_unbound netfs_write_collection_worker Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 netfs_wait_for_in_progress_stream+0x1c3/0x4d0 fs/netfs/misc.c:370 netfs_retry_writes+0x101/0x1710 fs/netfs/write_retry.c:215 netfs_collect_write_results fs/netfs/write_collect.c:348 [inline] netfs_write_collection+0x1e8f/0x2980 fs/netfs/write_collect.c:363 netfs_write_collection_worker+0x80/0xb0 fs/netfs/write_collect.c:438 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 2 locks held by kworker/u4:0/12: #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc900001e7bc0 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc900001e7bc0 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 1 lock held by khungtaskd/26: #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770 2 locks held by kworker/u4:2/31: #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc90000527bc0 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90000527bc0 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 2 locks held by kworker/u4:3/43: #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc900005e7bc0 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc900005e7bc0 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 2 locks held by kworker/u4:4/1034: #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc90002577bc0 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90002577bc0 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 2 locks held by kworker/u4:6/1038: #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc900025b7bc0 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc900025b7bc0 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 2 locks held by kworker/u4:8/1042: #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc900025f7bc0 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc900025f7bc0 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 2 locks held by kworker/u4:11/3000: #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321 #1: ffffc9000da0fbc0 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc9000da0fbc0 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321 2 locks held by getty/5112: #0: ffff888000fe10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900024be2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 3 locks held by syz.0.15/5848: #0: ffff8880003a80f8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1217 #1: ffff88804e3da428 (sb_writers#12){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3096 [inline] #1: ffff88804e3da428 (sb_writers#12){.+.+}-{0:0}, at: vfs_write+0x211/0xa90 fs/read_write.c:682 #2: ffff888042198500 (&ctx->wb_lock){+.+.}-{4:4}, at: netfs_writepages+0xa9/0x900 fs/netfs/write_issue.c:559 3 locks held by syz.1.19/5924: #0: ffff888000a94d38 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1217 #1: ffff88804e222428 (sb_writers#12){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3096 [inline] #1: ffff88804e222428 (sb_writers#12){.+.+}-{0:0}, at: vfs_write+0x211/0xa90 fs/read_write.c:682 #2: ffff888042199ec0 (&ctx->wb_lock){+.+.}-{4:4}, at: netfs_writepages+0xa9/0x900 fs/netfs/write_issue.c:559 3 locks held by syz.2.30/5975: #0: ffff888000cfc0f8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1217 #1: ffff8880446c0428 (sb_writers#12){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3096 [inline] #1: ffff8880446c0428 (sb_writers#12){.+.+}-{0:0}, at: vfs_write+0x211/0xa90 fs/read_write.c:682 #2: ffff88804219d240 (&ctx->wb_lock){+.+.}-{4:4}, at: netfs_writepages+0xa9/0x900 fs/netfs/write_issue.c:559 3 locks held by syz.3.37/6025: #0: ffff88803eae89b8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1217 #1: ffff888000f66428 (sb_writers#12){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3096 [inline] #1: ffff888000f66428 (sb_writers#12){.+.+}-{0:0}, at: vfs_write+0x211/0xa90 fs/read_write.c:682 #2: ffff88804219a530 (&ctx->wb_lock){+.+.}-{4:4}, at: netfs_writepages+0xa9/0x900 fs/netfs/write_issue.c:559 3 locks held by syz.4.51/6088: #0: ffff888042719b78 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1217 #1: ffff888032838428 (sb_writers#12){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3096 [inline] #1: ffff888032838428 (sb_writers#12){.+.+}-{0:0}, at: vfs_write+0x211/0xa90 fs/read_write.c:682 #2: ffff88804219aba0 (&ctx->wb_lock){+.+.}-{4:4}, at: netfs_writepages+0xa9/0x900 fs/netfs/write_issue.c:559 3 locks held by syz.5.52/6125: #0: ffff888052eac7f8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1217 #1: ffff888056956428 (sb_writers#12){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3096 [inline] #1: ffff888056956428 (sb_writers#12){.+.+}-{0:0}, at: vfs_write+0x211/0xa90 fs/read_write.c:682 #2: ffff88804219ec00 (&ctx->wb_lock){+.+.}-{4:4}, at: netfs_writepages+0xa9/0x900 fs/netfs/write_issue.c:559 3 locks held by syz.6.53/6170: #0: ffff888035a670f8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1217 #1: ffff88804e34a428 (sb_writers#12){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3096 [inline] #1: ffff88804e34a428 (sb_writers#12){.+.+}-{0:0}, at: vfs_write+0x211/0xa90 fs/read_write.c:682 #2: ffff88804219e590 (&ctx->wb_lock){+.+.}-{4:4}, at: netfs_writepages+0xa9/0x900 fs/netfs/write_issue.c:559 1 lock held by syz-executor/6173: #0: ffffffff8e144978 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline] #0: ffffffff8e144978 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:998 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 26 Comm: khungtaskd Not tainted 6.16.0-rc3-syzkaller-g78f4e737a53e #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:470 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245