INFO: task syz.2.9747:26255 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.9747      state:D stack:26584 pid:26255 tgid:26253 ppid:5671   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x16d9/0x5700 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7668
 rt_mutex_slowlock_block+0x55e/0x690 kernel/locking/rtmutex.c:1670
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
 rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
 __rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:562 [inline]
 mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:580
 nfsd_nl_svc_export_set_reqs_doit+0x132/0x1480 fs/nfsd/export.c:1057
 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
 genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2575
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1338 [inline]
 netlink_unicast+0x7f5/0x990 net/netlink/af_netlink.c:1364
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
 __sock_sendmsg net/socket.c:815 [inline]
 ____sys_sendmsg+0x565/0x870 net/socket.c:2713
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2767
 __sys_sendmsg net/socket.c:2799 [inline]
 __do_sys_sendmsg net/socket.c:2804 [inline]
 __se_sys_sendmsg net/socket.c:2802 [inline]
 __x64_sys_sendmsg+0x1b7/0x290 net/socket.c:2802
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4719fae159
RSP: 002b:00007f4718206028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f471a235fa0 RCX: 00007f4719fae159
RDX: 0000000004008090 RSI: 0000200000000140 RDI: 0000000000000003
RBP: 00007f471a04506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f471a236038 R14: 00007f471a235fa0 R15: 00007fff4e65a318
 </TASK>

Showing all locks held in the system:
locks held by rcuc/0/20: 2, last CPU#0:
 #0: ffffffff8e059540 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3d/0x420 kernel/softirq.c:186
 #1: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3d/0x420 kernel/softirq.c:186
locks held by khungtaskd/38: 1, last CPU#0:
 #0: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by getty/5342: 2, on CPU#1:
 #0: ffff8880356a30a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900044c32e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
locks held by syz.3.7561/21652: 2, on CPU#0:
 #0: ffffffff8f647240 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff8e4f86d8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x53b/0x1a90 fs/nfsd/nfsctl.c:2057
locks held by syz.2.9747/26255: 2, on CPU#1:
 #0: ffffffff8f647240 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff8e4f86d8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_svc_export_set_reqs_doit+0x132/0x1480 fs/nfsd/export.c:1057
locks held by syz.4.11013/28941: 3, on CPU#1:
 #0: ffffffff8f647240 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffff88803786e928 (nlk_cb_mutex-GENERIC){+.+.}-{4:4}, at: __netlink_dump_start+0xf4/0x7b0 net/netlink/af_netlink.c:2429
 #2: ffffffff8e4f86d8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_svc_export_get_reqs_dumpit+0xf7/0xc40 fs/nfsd/export.c:674
locks held by syz.0.11980/31066: 3, on CPU#1:
 #0: ffffffff8f647240 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffff888038954928 (nlk_cb_mutex-GENERIC){+.+.}-{4:4}, at: __netlink_dump_start+0xf4/0x7b0 net/netlink/af_netlink.c:2429
 #2: ffffffff8e4f86d8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_expkey_get_reqs_dumpit+0xfb/0xd60 fs/nfsd/export.c:347
locks held by syz-executor/31688: 4, last CPU#1:
 #0: ffffffff8fb245e8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff8fb245e8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8fb245e8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:595
 #1: ffffffff8f5d57b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #1: ffffffff8f5d57b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:366 [inline]
 #1: ffffffff8f5d57b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0xc10/0x1c30 net/core/rtnetlink.c:4219
 #2: ffff88813ff77238 (&root->kernfs_rwsem){++++}-{4:4}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #2: ffff88813ff77238 (&root->kernfs_rwsem){++++}-{4:4}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #2: ffff88813ff77238 (&root->kernfs_rwsem){++++}-{4:4}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
 #2: ffff88813ff77238 (&root->kernfs_rwsem){++++}-{4:4}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
 #3: ffff88813ff772c0 (&root->kernfs_iattr_rwsem){++++}-{4:4}, at: rt_mutex_slowunlock+0xbf/0xa30 kernel/locking/rtmutex.c:1430
locks held by syz.1.12285/31755: 3, last CPU#1:
 #0: ffffffff8f343ed8 (lock#3){+.+.}-{4:4}, at: cma_release_port drivers/infiniband/core/cma.c:1998 [inline]
 #0: ffffffff8f343ed8 (lock#3){+.+.}-{4:4}, at: _destroy_id+0xb99/0x13d0 drivers/infiniband/core/cma.c:2076
 #1: ffff88803b8ea0e8 (&xa->xa_lock#10){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #1: ffff88803b8ea0e8 (&xa->xa_lock#10){+.+.}-{3:3}, at: xa_erase+0x31/0xf0 lib/xarray.c:1672
 #2: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #2: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #2: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #2: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e2/0x400 kernel/locking/spinlock_rt.c:57
locks held by syz.5.12286/31759: 3, last CPU#1:
 #0: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: is_bpf_text_address+0x26/0x2b0 kernel/bpf/core.c:750
 #1: ffffffff8e1c3cc0 (rcu_read_lock){....}-{1:3}, at: rt_mutex_slowunlock+0xbf/0xa30 kernel/locking/rtmutex.c:1430
 #2: ffff8880b8728558 (hrtimer_bases.lock){-...}-{2:2}, at: class_raw_spinlock_constructor include/linux/spinlock.h:559 [inline]
 #2: ffff8880b8728558 (hrtimer_bases.lock){-...}-{2:2}, at: __hrtimer_rearm_deferred+0x99/0x4d0 kernel/time/hrtimer.c:2188
locks held by syz.6.12288/31764: 2, last CPU#0:
 #0: ffffffff8f647240 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffff8880631de310 (&devlink->lock_key#7){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:125 [inline]
 #1: ffff8880631de310 (&devlink->lock_key#7){+.+.}-{4:4}, at: devlink_get_from_attrs_lock+0x360/0x490 net/devlink/netlink.c:235

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
 nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
 trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd7/0x1030 kernel/hung_task.c:561
 kthread+0x38b/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31759 Comm: syz.5.12286 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:lock_acquire+0xa8/0x350 kernel/locking/lockdep.c:5918
Code: 3d 8c 30 10 0e 00 0f 84 e4 00 00 00 65 8b 05 af 0a 04 11 85 c0 0f 85 d5 00 00 00 65 48 8b 2d b7 c4 03 11 83 bd 0c 0c 00 00 00 <0f> 85 c0 00 00 00 48 89 5c 24 08 4c 89 fb 9c 41 5f fa 48 c7 c7 5c
RSP: 0018:ffffc9000f027280 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 8000000000000001
RDX: 0000000000000001 RSI: ffffffff8b5b1a0c RDI: 1ffff110170e8d9d
RBP: ffff888060bd8000 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f64550 R12: ffff8880b8746ce8
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
FS:  00007f48f98b66c0(0000) GS:ffff888125cc3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f220ff8 CR3: 000000006c956000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __rt_spin_trylock kernel/locking/spinlock_rt.c:126 [inline]
 rt_spin_trylock+0xfc/0x2b0 kernel/locking/spinlock_rt.c:135
 alloc_from_pcs mm/slub.c:4844 [inline]
 slab_alloc_node mm/slub.c:4984 [inline]
 kmem_cache_alloc_noprof+0x182/0x690 mm/slub.c:5010
 __build_skb+0x62/0x440 net/core/skbuff.c:494
 netlink_alloc_large_skb+0x74/0x110 net/netlink/af_netlink.c:1210
 netlink_sendmsg+0x5d4/0xb40 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
 __sock_sendmsg net/socket.c:815 [inline]
 sock_sendmsg+0x1ca/0x2d0 net/socket.c:838
 splice_to_socket+0xb61/0x12a0 fs/splice.c:884
 do_splice_from fs/splice.c:936 [inline]
 direct_splice_actor+0x104/0x160 fs/splice.c:1159
 splice_direct_to_actor+0x586/0xcc0 fs/splice.c:1103
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x19b/0x2a0 fs/splice.c:1228
 do_sendfile+0x540/0x7e0 fs/read_write.c:1371
 __do_sys_sendfile64 fs/read_write.c:1432 [inline]
 __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1418
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f48fb65e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f48f98b6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f48fb8e5fa0 RCX: 00007f48fb65e159
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000003
RBP: 00007f48fb6f506b R08: 0000000000000000 R09: 0000000000000000
R10: 7fffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f48fb8e6038 R14: 00007f48fb8e5fa0 R15: 00007fff92407888
 </TASK>