INFO: task syz.5.2063:15550 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.2063 state:D stack:27496 pid:15550 tgid:15549 ppid:14100 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6908 __schedule_loop kernel/sched/core.c:6990 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7005 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7062 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776 device_lock include/linux/device.h:895 [inline] usbdev_open+0x1b6/0x870 drivers/usb/core/devio.c:1054 chrdev_open+0x234/0x6a0 fs/char_dev.c:411 do_dentry_open+0x6d8/0x1660 fs/open.c:949 vfs_open+0x82/0x3f0 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x208c/0x31a0 fs/namei.c:4830 do_file_open+0x20e/0x430 fs/namei.c:4859 do_sys_openat2+0x10d/0x1e0 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe198f5cfce RSP: 002b:00007fe199e21b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fe199e226c0 RCX: 00007fe198f5cfce RDX: 0000000000101301 RSI: 00007fe199e21c00 RDI: ffffffffffffff9c RBP: 00007fe199e21c00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007fe199216038 R14: 00007fe199215fa0 R15: 00007fff91c00c28 Showing all locks held in the system: 5 locks held by kworker/1:0/24: 1 lock held by khungtaskd/30: #0: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8e7e93e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 1 lock held by klogd/5168: 2 locks held by getty/5564: #0: ffff8880343990a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211 1 lock held by syz-executor/5804: 3 locks held by kworker/1:8/14209: 1 lock held by syz.5.2063/15550: #0: ffff88802afb7198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #0: ffff88802afb7198 (&dev->mutex){....}-{4:4}, at: usbdev_open+0x1b6/0x870 drivers/usb/core/devio.c:1054 1 lock held by syz.6.2329/16890: 1 lock held by syz.7.2331/16907: 4 locks held by syz.2.2334/16914: 7 locks held by syz.2.2334/16915: #0: ffffffff8e7d59c0 (console_lock){+.+.}-{0:0}, at: do_fb_ioctl+0x1d9/0x7e0 drivers/video/fbdev/core/fb_chrdev.c:86 #1: ffff888026ee5078 (&fb_info->lock){+.+.}-{4:4}, at: lock_fb_info include/linux/fb.h:619 [inline] #1: ffff888026ee5078 (&fb_info->lock){+.+.}-{4:4}, at: do_fb_ioctl+0x1e3/0x7e0 drivers/video/fbdev/core/fb_chrdev.c:87 #2: ffff888026cf7280 (&helper->lock){+.+.}-{4:4}, at: drm_fb_helper_pan_display+0xd6/0xa40 drivers/gpu/drm/drm_fb_helper.c:1260 #3: ffff888026ec8130 (&dev->master_mutex){+.+.}-{4:4}, at: drm_master_internal_acquire+0x21/0x80 drivers/gpu/drm/drm_auth.c:435 #4: ffff888026cf7098 (&client->modeset_mutex){+.+.}-{4:4}, at: drm_client_modeset_commit_locked+0x4c/0x580 drivers/gpu/drm/drm_client_modeset.c:1205 #5: ffffc9000cbaf560 (crtc_ww_class_acquire){+.+.}-{0:0}, at: drm_client_modeset_commit_atomic+0xc4/0x7e0 drivers/gpu/drm/drm_client_modeset.c:1043 #6: ffffc9000cbaf588 (crtc_ww_class_mutex){+.+.}-{4:4}, at: drm_client_modeset_commit_atomic+0xc4/0x7e0 drivers/gpu/drm/drm_client_modeset.c:1043 2 locks held by syz.2.2334/16916: #0: ffffffff90610c28 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff90610c28 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff90610c28 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dellink+0x307/0xb40 net/core/rtnetlink.c:3562 #1: ffffffff8e7f4ff8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x1d7/0x230 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+0x141/0x190 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xd25/0x1050 kernel/hung_task.c:515 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x754/0xd80 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: 16914 Comm: syz.2.2334 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:_copy_from_user+0x4/0xd0 lib/usercopy.c:17 Code: 5f 7f fd eb e4 48 89 df e8 69 5f 7f fd eb 85 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa <41> 55 49 89 fd 41 54 55 48 89 d5 53 48 89 f3 e8 38 e1 12 fd be a9 RSP: 0018:ffffc9000e497a58 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffc9000e497d78 RCX: 0000000000000000 RDX: 0000000000000038 RSI: 00002000001a6340 RDI: ffffc9000e497a88 RBP: ffffc9000e497b90 R08: ffffc9000e497a88 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000000 R12: 1ffff92001c92f4d R13: 0000000000000000 R14: 00002000001a6340 R15: dffffc0000000000 FS: 00007f30dabe86c0(0000) GS:ffff888124445000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2fb16ff8 CR3: 00000000a984c000 CR4: 00000000003526f0 Call Trace: copy_from_user include/linux/uaccess.h:223 [inline] copy_msghdr_from_user+0x9f/0x4f0 net/socket.c:2522 recvmsg_copy_msghdr net/socket.c:2778 [inline] ___sys_recvmsg+0xdd/0x1a0 net/socket.c:2850 do_recvmmsg+0x301/0x760 net/socket.c:2949 __sys_recvmmsg net/socket.c:3023 [inline] __do_sys_recvmmsg net/socket.c:3046 [inline] __se_sys_recvmmsg net/socket.c:3039 [inline] __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3039 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f30d9d9c799 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:00007f30dabe8028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f30da016090 RCX: 00007f30d9d9c799 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000006 RBP: 00007f30d9e32bd9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f30da016128 R14: 00007f30da016090 R15: 00007fff99b43758