INFO: task syz.0.430:7498 blocked for more than 143 seconds. Not tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.430 state:D stack:23072 pid:7498 tgid:7498 ppid:6883 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6675 __schedule_loop kernel/sched/core.c:6752 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6767 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752 nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:625 nfsd_umount+0x43/0xd0 fs/nfsd/nfsctl.c:1428 deactivate_locked_super+0xc6/0x130 fs/super.c:473 put_fs_context+0x94/0x780 fs/fs_context.c:516 fscontext_release+0x62/0x80 fs/fsopen.c:73 __fput+0x241/0x880 fs/file_table.c:431 task_work_run+0x251/0x310 kernel/task_work.c:228 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f452777dff9 RSP: 002b:00007ffca40a8558 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f4527937a80 RCX: 00007f452777dff9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f4527937a80 R08: 0000000000000006 R09: 00007ffca40a884f R10: 00000000003ff554 R11: 0000000000000246 R12: 0000000000037eb0 R13: 00007ffca40a8660 R14: 0000000000000032 R15: ffffffffffffffff Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6720 3 locks held by kworker/u8:8/2567: 2 locks held by getty/4989: #0: ffff88814c5520a0 (&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+0x6a6/0x1e00 drivers/tty/n_tty.c:2211 2 locks held by syz.4.282/6681: #0: ffffffff8fd374b0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8ec19028 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nl_listener_set_doit+0x12d/0x1a90 fs/nfsd/nfsctl.c:1964 2 locks held by syz.0.430/7498: #0: ffff888057a5e0e0 (&type->s_umount_key#82){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff888057a5e0e0 (&type->s_umount_key#82){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888057a5e0e0 (&type->s_umount_key#82){+.+.}-{3:3}, at: deactivate_super+0xb5/0xf0 fs/super.c:505 #1: ffffffff8ec19028 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:625 2 locks held by syz.4.574/8263: #0: ffffffff8fd374b0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8ec19028 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_nl_listener_set_doit+0x12d/0x1a90 fs/nfsd/nfsctl.c:1964 2 locks held by syz.1.595/8347: #0: ffff88805ab1a0e0 (&type->s_umount_key#82){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff88805ab1a0e0 (&type->s_umount_key#82){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88805ab1a0e0 (&type->s_umount_key#82){+.+.}-{3:3}, at: deactivate_super+0xb5/0xf0 fs/super.c:505 #1: ffffffff8ec19028 (nfsd_mutex){+.+.}-{3:3}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:625 1 lock held by syz.3.904/9690: 1 lock held by syz.5.902/9682: 5 locks held by syz.2.906/9708: 1 lock held by syz.4.912/9705: 2 locks held by syz.4.912/9706: #0: ffff88814c5c9e18 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1609 [inline] #0: ffff88814c5c9e18 (sk_lock-AF_INET6){+.+.}-{0:0}, at: sctp_sendmsg+0xbb9/0x3520 net/sctp/socket.c:1970 #1: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #1: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #1: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: sctp_v6_get_dst+0x565/0x1e20 net/sctp/ipv6.c:322 1 lock held by syz.4.912/9707: #0: ffff88814c5c9e18 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1609 [inline] #0: ffff88814c5c9e18 (sk_lock-AF_INET6){+.+.}-{0:0}, at: sctp_getsockopt+0x13a/0xbb0 net/sctp/socket.c:8091 1 lock held by syz.4.912/9709: #0: ffff88814c5c9e18 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1609 [inline] #0: ffff88814c5c9e18 (sk_lock-AF_INET6){+.+.}-{0:0}, at: sctp_setsockopt+0x203/0x11c0 net/sctp/socket.c:4600 1 lock held by syz.4.912/9710: #0: ffff88814c5c9e18 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1609 [inline] #0: ffff88814c5c9e18 (sk_lock-AF_INET6){+.+.}-{0:0}, at: sctp_getsockopt+0x13a/0xbb0 net/sctp/socket.c:8091 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #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:223 [inline] watchdog+0xff4/0x1040 kernel/hung_task.c:379 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/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: 9708 Comm: syz.2.906 Not tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:fast_imageblit drivers/video/fbdev/core/sysimgblt.c:261 [inline] RIP: 0010:sys_imageblit+0x1c34/0x2b00 drivers/video/fbdev/core/sysimgblt.c:326 Code: 04 00 00 41 0f b6 58 ff 48 c1 eb 03 23 5c 24 10 bf 10 00 00 00 89 de e8 6a c1 83 fc 83 fb 0f 0f 87 ce 06 00 00 e8 1c bd 83 fc <48> 8d 84 24 c0 00 00 00 48 8d 1c 98 48 89 d8 48 c1 e8 03 48 b9 00 RSP: 0018:ffffc9001213f020 EFLAGS: 00000246 RAX: ffffffff85111e94 RBX: 0000000000000000 RCX: 0000000000040000 RDX: ffffc9000a9f7000 RSI: 000000000003ffff RDI: 0000000000040000 RBP: ffffc9001213f198 R08: ffffffff85111e86 R09: ffffffff8511158d R10: 0000000000000003 R11: ffff888024febc00 R12: 000000000000029e R13: 1ffff110286fa82f R14: ffff8881437d4178 R15: 00000000000003e0 FS: 00007f480a6a56c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fac269abf98 CR3: 00000000303d8000 CR4: 0000000000350ef0 Call Trace: drm_fbdev_shmem_defio_imageblit+0x2e/0x100 drivers/gpu/drm/drm_fbdev_shmem.c:39 bit_putcs+0x18bc/0x1db0 fbcon_putcs+0x2e2/0x450 drivers/video/fbdev/core/fbcon.c:1308 fbcon_redraw+0x2fb/0x400 drivers/video/fbdev/core/fbcon.c:1675 fbcon_scroll+0x3a9/0x680 drivers/video/fbdev/core/fbcon.c:1848 con_scroll+0x753/0x9e0 drivers/tty/vt/vt.c:579 lf drivers/tty/vt/vt.c:1443 [inline] vc_con_write_normal drivers/tty/vt/vt.c:2999 [inline] do_con_write+0x1141/0x4c30 drivers/tty/vt/vt.c:3096 con_write+0x26/0x40 drivers/tty/vt/vt.c:3434 process_output_block drivers/tty/n_tty.c:574 [inline] n_tty_write+0xd64/0x1230 drivers/tty/n_tty.c:2389 iterate_tty_write drivers/tty/tty_io.c:1015 [inline] file_tty_write+0x548/0x9b0 drivers/tty/tty_io.c:1090 new_sync_write fs/read_write.c:590 [inline] vfs_write+0xa6f/0xc90 fs/read_write.c:683 ksys_write+0x183/0x2b0 fs/read_write.c:736 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: 0033:0x7f480997dff9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f480a6a5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f4809b36058 RCX: 00007f480997dff9 RDX: 0000000000001006 RSI: 0000000020002080 RDI: 0000000000000007 RBP: 00007f48099f0296 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f4809b36058 R15: 00007ffe2af50e28