INFO: task kworker/u8:9:6766 blocked for more than 143 seconds. Not tainted 6.13.0-rc5-syzkaller-00006-g56e6a3499e14 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:9 state:D stack:20272 pid:6766 tgid:6766 ppid:2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:2) Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x17fb/0x4be0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6848 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905 __mutex_lock_common kernel/locking/mutex.c:665 [inline] __mutex_lock+0x7e7/0xee0 kernel/locking/mutex.c:735 exfat_write_inode+0xe5/0x1a0 fs/exfat/inode.c:108 write_inode fs/fs-writeback.c:1525 [inline] __writeback_single_inode+0x708/0x10d0 fs/fs-writeback.c:1745 writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2047 wb_writeback+0x427/0xb80 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+0xb94/0x1080 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 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 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744 2 locks held by kworker/u8:4/68: #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310 #1: ffffc9000153fd00 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc9000153fd00 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310 3 locks held by kworker/u8:5/799: 2 locks held by getty/5576: #0: ffff888031deb0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211 3 locks held by syz-executor/5824: 4 locks held by kworker/u8:9/6766: #0: ffff8880202cd148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff8880202cd148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310 #1: ffffc9000b84fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc9000b84fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310 #2: ffff888021ef00e0 (&type->s_umount_key#58){++++}-{4:4}, at: super_trylock_shared+0x22/0xf0 fs/super.c:562 #3: ffff8880687f20e8 (&sbi->s_lock){+.+.}-{4:4}, at: exfat_write_inode+0xe5/0x1a0 fs/exfat/inode.c:108 2 locks held by syz-executor/7397: 3 locks held by kworker/u8:11/7719: 2 locks held by syz-executor/8081: #0: ffffffff8f0417e8 (bio_slab_lock){+.+.}-{4:4}, at: bio_put_slab block/bio.c:140 [inline] #0: ffffffff8f0417e8 (bio_slab_lock){+.+.}-{4:4}, at: bioset_exit+0x42f/0x650 block/bio.c:1755 #1: ffffffff8e93cec0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:4565 2 locks held by syz.0.288/8740: #0: ffff888021ef00e0 (&type->s_umount_key#58){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff888021ef00e0 (&type->s_umount_key#58){++++}-{4:4}, at: super_lock+0x27c/0x400 fs/super.c:120 #1: ffff88814372a7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff88814372a7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x26e/0xb50 fs/fs-writeback.c:2819 2 locks held by syz.5.330/9269: 4 locks held by dhcpcd-run-hook/9287: 8 locks held by syz.2.334/9290: #0: ffff888034c315f8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x254/0x320 fs/file.c:1191 #1: ffff88803645e420 (sb_writers#8){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2964 [inline] #1: ffff88803645e420 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x225/0xd30 fs/read_write.c:675 #2: ffff888024214088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1ea/0x500 fs/kernfs/file.c:325 #3: ffff88801d6d51e8 (kn->active#57){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x20e/0x500 fs/kernfs/file.c:326 #4: ffffffff8e7eba48 (system_transition_mutex){+.+.}-{4:4}, at: software_resume+0x45/0x3d0 kernel/power/hibernate.c:992 #5: ffffffff8f04f3a8 (major_names_lock){+.+.}-{4:4}, at: blk_request_module+0x33/0x1b0 block/genhd.c:806 #6: ffffffff8f96e788 (disks_mutex){+.+.}-{4:4}, at: md_alloc+0x36/0xde0 drivers/md/md.c:5857 #7: ffffffff8f0417e8 (bio_slab_lock){+.+.}-{4:4}, at: bio_find_or_create_slab block/bio.c:122 [inline] #7: ffffffff8f0417e8 (bio_slab_lock){+.+.}-{4:4}, at: bioset_init+0x23f/0x820 block/bio.c:1796 2 locks held by syz.2.334/9295: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-rc5-syzkaller-00006-g56e6a3499e14 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 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:234 [inline] watchdog+0xff6/0x1040 kernel/hung_task.c:397 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 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5175 Comm: syslogd Not tainted 6.13.0-rc5-syzkaller-00006-g56e6a3499e14 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:__kernel_text_address+0x0/0x40 kernel/extable.c:78 Code: c1 03 38 c1 7c c3 48 c7 c7 40 12 18 90 e8 f8 36 99 00 eb b5 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <66> 0f 1f 00 53 48 89 fb e8 43 00 00 00 85 c0 0f 95 c0 48 c7 c1 00 RSP: 0018:ffffc9000374f458 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffc9000374f4c8 RCX: 0000000080000000 RDX: dffffc0000000000 RSI: ffffc90003748000 RDI: ffffffff8bc06783 RBP: ffffc9000374f510 R08: ffffc9000374ff00 R09: 0000000000000000 R10: ffffc9000374f4d0 R11: fffff520006e9e9c R12: ffff88807db49e00 R13: ffffffff818b3980 R14: dffffc0000000000 R15: 1ffff920006e9e99 FS: 00007f4f403b3380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f72811452d8 CR3: 000000002ee4e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0xfd/0x150 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2353 [inline] slab_free mm/slub.c:4613 [inline] kfree+0x196/0x430 mm/slub.c:4761 skb_kfree_head net/core/skbuff.c:1086 [inline] skb_free_head net/core/skbuff.c:1098 [inline] skb_release_data+0x6a0/0x8a0 net/core/skbuff.c:1125 skb_release_all net/core/skbuff.c:1190 [inline] __kfree_skb net/core/skbuff.c:1204 [inline] consume_skb+0x9f/0xf0 net/core/skbuff.c:1436 __unix_dgram_recvmsg+0xcea/0x12f0 net/unix/af_unix.c:2521 sock_recvmsg_nosec net/socket.c:1033 [inline] sock_recvmsg+0x22f/0x280 net/socket.c:1055 sock_read_iter+0x2c4/0x3d0 net/socket.c:1125 new_sync_read fs/read_write.c:484 [inline] vfs_read+0x991/0xb70 fs/read_write.c:565 ksys_read+0x18f/0x2b0 fs/read_write.c:708 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: 0033:0x7f4f40507b6a Code: 00 3d 00 00 41 00 75 0d 50 48 8d 3d 2d 08 0a 00 e8 ea 7d 01 00 31 c0 e9 07 ff ff ff 64 8b 04 25 18 00 00 00 85 c0 75 1b 0f 05 <48> 3d 00 f0 ff ff 76 6c 48 8b 15 8f a2 0d 00 f7 d8 64 89 02 48 83 RSP: 002b:00007fffcd3e96b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f4f40507b6a RDX: 00000000000000ff RSI: 000056205ae15950 RDI: 0000000000000000 RBP: 000056205ae15910 R08: 0000000000000001 R09: 0000000000000000 R10: 00007f4f406a63a3 R11: 0000000000000246 R12: 000056205ae15999 R13: 000056205ae15950 R14: 0000000000000000 R15: 00007f4f406eaa80