INFO: task syz.0.4172:15513 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.4172 state:D stack:26424 pid:15513 tgid:15512 ppid:5818 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x164/0x360 kernel/sched/core.c:7008 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776 nfsd_nl_listener_get_doit+0x10a/0x5e0 fs/nfsd/nfsctl.c:2053 genl_family_rcv_msg_doit+0x22a/0x330 net/netlink/genetlink.c:1114 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] genl_rcv_msg+0x61c/0x7a0 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fad5099c819 RSP: 002b:00007fad4ebf6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fad50c15fa0 RCX: 00007fad5099c819 RDX: 0000000020048000 RSI: 0000200000000140 RDI: 0000000000000003 RBP: 00007fad50a32c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fad50c16038 R14: 00007fad50c15fa0 R15: 00007ffe14f289d8 Showing all locks held in the system: 1 lock held by khungtaskd/32: #0: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5574: #0: ffff888036c400a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000331e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211 2 locks held by udevd/6521: 2 locks held by syz.5.4160/15473: #0: ffffffff8fc3e630 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8ea86b48 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x141/0x1670 fs/nfsd/nfsctl.c:1903 2 locks held by syz.0.4172/15513: #0: ffffffff8fc3e630 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8ea86b48 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_get_doit+0x10a/0x5e0 fs/nfsd/nfsctl.c:2053 1 lock held by syz-executor/15940: #0: ffffffff8e7648b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #0: ffffffff8e7648b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961 3 locks held by syz.6.6229/20413: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 32 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [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:346 [inline] watchdog+0xfd9/0x1030 kernel/hung_task.c:515 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 20413 Comm: syz.6.6229 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:mt_find+0x267/0x630 lib/maple_tree.c:6498 Code: 89 f7 48 c7 c6 90 99 f8 8f e8 25 70 1d f6 49 83 fe 03 74 26 41 83 fe 02 74 19 4c 89 e7 e8 21 78 00 00 83 bc 24 a8 00 00 00 01 <75> 1b e8 82 6a 1d f6 eb b9 e8 7b 6a 1d f6 eb 15 e8 74 6a 1d f6 45 RSP: 0018:ffffc9001e73e820 EFLAGS: 00000297 RAX: ffff88801f367640 RBX: 1ffff92003ce7d0c RCX: 1ffff92003ce7d13 RDX: ffffc9001e73e890 RSI: ffff88802abe2400 RDI: ffffc9001e73e8cf RBP: ffffc9001e73e950 R08: ffff88801f7f3d00 R09: 0000000000000004 R10: 0000000000000003 R11: 0000000000000000 R12: ffffc9001e73e880 R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125454000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f87325e92f8 CR3: 00000000297f6000 CR4: 0000000000350ef0 Call Trace: find_vma+0xed/0x160 mm/mmap.c:907 gup_vma_lookup mm/gup.c:1275 [inline] __get_user_pages+0x3ba/0x29d0 mm/gup.c:1396 __get_user_pages_locked mm/gup.c:1692 [inline] get_dump_page+0x1b5/0x410 mm/gup.c:2192 dump_user_range+0x20a/0x12d0 fs/coredump.c:1367 elf_core_dump+0x34c2/0x3ad0 fs/binfmt_elf.c:2110 coredump_write+0x1216/0x1910 fs/coredump.c:1050 do_coredump fs/coredump.c:1127 [inline] vfs_coredump+0x36a9/0x4280 fs/coredump.c:1201 get_signal+0x1107/0x1330 kernel/signal.c:3019 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop kernel/entry/common.c:98 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline] irqentry_exit+0x176/0x620 kernel/entry/common.c:219 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f87322527f7 Code: e8 8e fa ff ff 89 f2 48 8d 3d 8d 40 1b 00 48 8d 35 6c fa 1d 00 31 c0 e8 e7 f8 ff ff 0f 1f 80 00 00 00 00 53 89 fb 48 83 ec 10 <64> 8b 04 25 a4 ff ff ff 85 c0 74 2a 89 fe 31 c0 bf 3c 00 00 00 e8 RSP: 002b:00007f87331ef120 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007f873239c819 RDX: 00007f87331ef140 RSI: 00007f87331ef270 RDI: 000000000000000b RBP: 00007f8732432c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f8732616038 R14: 00007f8732615fa0 R15: 00007ffef0851cb8