INFO: task syz.2.422:7355 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.422 state:D stack:27200 pid:7355 tgid:7354 ppid:5631 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821 nfsd_nl_version_get_doit+0x17c/0xd20 fs/nfsd/nfsctl.c:1889 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:2556 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775 __sock_sendmsg net/socket.c:790 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2684 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738 __sys_sendmsg net/socket.c:2770 [inline] __do_sys_sendmsg net/socket.c:2775 [inline] __se_sys_sendmsg net/socket.c:2773 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff93119ce59 RSP: 002b:00007ff931fc5028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007ff931415fa0 RCX: 00007ff93119ce59 RDX: 0000000004000080 RSI: 0000200000000100 RDI: 0000000000000003 RBP: 00007ff931232e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff931416038 R14: 00007ff931415fa0 R15: 00007ffed9489ef8 INFO: task syz.0.428:7373 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.428 state:D stack:26488 pid:7373 tgid:7372 ppid:5623 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821 nfsd_nl_rpc_status_get_dumpit+0xdc/0x13b0 fs/nfsd/nfsctl.c:1510 genl_dumpit+0x10b/0x1b0 net/netlink/genetlink.c:1026 netlink_dump+0x711/0xee0 net/netlink/af_netlink.c:2331 __netlink_dump_start+0x589/0x7b0 net/netlink/af_netlink.c:2446 genl_family_rcv_msg_dumpit+0x213/0x310 net/netlink/genetlink.c:1075 genl_family_rcv_msg net/netlink/genetlink.c:1191 [inline] genl_rcv_msg+0x5e1/0x7a0 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775 __sock_sendmsg net/socket.c:790 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2684 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738 __sys_sendmsg net/socket.c:2770 [inline] __do_sys_sendmsg net/socket.c:2775 [inline] __se_sys_sendmsg net/socket.c:2773 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fafd379ce59 RSP: 002b:00007fafd4682028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fafd3a15fa0 RCX: 00007fafd379ce59 RDX: 0000000000000080 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007fafd3832e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fafd3a16038 R14: 00007fafd3a15fa0 R15: 00007fffa32e6db8 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8e959c20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5380: #0: ffff888035aef0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211 2 locks held by syz.4.377/7225: #0: ffffffff8fe5b2e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8ec8e2a0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x2b9/0xc30 fs/nfsd/nfsctl.c:1660 2 locks held by syz.2.422/7355: #0: ffffffff8fe5b2e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8ec8e2a0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_version_get_doit+0x17c/0xd20 fs/nfsd/nfsctl.c:1889 3 locks held by syz.0.428/7373: #0: ffffffff8fe5b2e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffff88807a9ad6e8 (nlk_cb_mutex-GENERIC){+.+.}-{4:4}, at: __netlink_dump_start+0xf4/0x7b0 net/netlink/af_netlink.c:2410 #2: ffffffff8ec8e2a0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_rpc_status_get_dumpit+0xdc/0x13b0 fs/nfsd/nfsctl.c:1510 2 locks held by syz.5.2135/12035: #0: ffffffff8fe5b2e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8ec8e2a0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_get_doit+0x1c0/0x790 fs/nfsd/nfsctl.c:1754 2 locks held by syz.3.2177/12166: 1 lock held by cmp/12268: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65 trigger_all_cpu_backtrace include/linux/nmi.h:162 [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+0x388/0x470 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 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 12269 Comm: rm Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline] RIP: 0010:lock_release+0x259/0x3c0 kernel/locking/lockdep.c:5891 Code: 41 8d 45 ff 41 89 c5 7f d0 4c 89 ff 4c 89 f6 48 8b 54 24 18 e8 28 2f 00 00 48 8b 5c 24 08 48 c7 c7 b4 a5 25 8e e8 47 6d 11 0a ff ff ff ff 65 0f c1 05 0a 8f 9d 11 83 f8 01 75 2e 9c 58 a9 00 RSP: 0000:ffffc90004d6f888 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 0000000000000202 RCX: 0000000080000002 RDX: 0000000000000003 RSI: ffffffff8e25a5b4 RDI: ffffffff8c2a9f80 RBP: ffff88804db66918 R08: ffffffff823fc60a R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8e959ce0 R12: 0000000000000003 R13: 0000000000000003 R14: ffffffff8e959ce0 R15: ffff88804db65d00 FS: 0000000000000000(0000) GS:ffff888125326000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc9c14bc068 CR3: 0000000057bb8000 CR4: 00000000003526f0 Call Trace: rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock_sched include/linux/rcupdate.h:962 [inline] pfn_valid+0x3b2/0x480 include/linux/mmzone.h:2280 page_table_check_set+0x25/0x510 mm/page_table_check.c:105 page_table_check_ptes_set include/linux/page_table_check.h:83 [inline] set_ptes include/linux/pgtable.h:447 [inline] set_pte_range+0x7ef/0x840 mm/memory.c:5588 finish_fault+0xe65/0x1220 mm/memory.c:5724 do_cow_fault mm/memory.c:5902 [inline] do_fault mm/memory.c:5996 [inline] do_pte_missing+0x1f1e/0x34b0 mm/memory.c:4566 handle_pte_fault mm/memory.c:6379 [inline] __handle_mm_fault mm/memory.c:6517 [inline] handle_mm_fault+0x1b36/0x3080 mm/memory.c:6686 do_user_addr_fault+0xa4d/0x1340 arch/x86/mm/fault.c:1343 handle_page_fault arch/x86/mm/fault.c:1483 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595 RIP: 0033:0x7fc9c17b6ff2 Code: 0f 60 c0 66 0f 61 c0 66 0f 70 c0 00 48 83 fa 10 72 76 48 83 fa 20 77 12 0f 11 44 17 f0 0f 11 07 c3 0f 11 47 e0 0f 11 47 f0 c3 <0f> 11 07 0f 11 47 10 48 01 d7 48 83 fa 40 76 e7 0f 11 40 20 0f 11 RSP: 002b:00007ffc5d0cc078 EFLAGS: 00010206 RAX: 00007fc9c14bc068 RBX: 0000000000000004 RCX: 00007fc9c14be6d0 RDX: 0000000000000f98 RSI: 0000000000000000 RDI: 00007fc9c14bc068 RBP: 00007ffc5d0cc440 R08: 00007fc9c14bc068 R09: 0000000000000003 R10: 0000000000000812 R11: 00007ffc5d0cc528 R12: 00007ffc5d0cc128 R13: 00007fc9c178bab0 R14: 00007ffc5d0cc4e0 R15: 00007fc9c14bd000