INFO: task syz-executor.0:5446 blocked for more than 143 seconds. Not tainted 6.8.0-rc1-next-20240124-syzkaller-g8bf1262c53f5 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:27888 pid:5446 tgid:5445 ppid:5423 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5400 [inline] __schedule+0xf15/0x5ce0 kernel/sched/core.c:6727 __schedule_loop kernel/sched/core.c:6804 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6819 schedule_timeout+0x258/0x2a0 kernel/time/timer.c:2159 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common+0x3de/0x5f0 kernel/sched/completion.c:116 __flush_workqueue+0x3e0/0x1340 kernel/workqueue.c:3199 nbd_start_device_ioctl drivers/block/nbd.c:1443 [inline] __nbd_ioctl drivers/block/nbd.c:1504 [inline] nbd_ioctl+0x308/0xd60 drivers/block/nbd.c:1544 blkdev_ioctl+0x2f7/0x770 block/ioctl.c:636 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl fs/ioctl.c:857 [inline] __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7f9e55e780e9 RSP: 002b:00007f9e570020d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f9e55f7bf60 RCX: 00007f9e55e780e9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 00007f9e55ed2c9b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f9e55f7bf60 R15: 00007ffe38506208 Showing all locks held in the system: 2 locks held by kworker/1:0/23: #0: ffff8880b953ccd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:559 #1: ffffc900001d7d80 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x824/0x16e0 kernel/workqueue.c:2609 1 lock held by khungtaskd/29: #0: ffffffff8d7b0c20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #0: ffffffff8d7b0c20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #0: ffffffff8d7b0c20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x75/0x340 kernel/locking/lockdep.c:6614 2 locks held by kworker/u5:0/51: #0: ffff88802009d538 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x7ba/0x16e0 kernel/workqueue.c:2608 #1: ffffc90000bc7d80 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x824/0x16e0 kernel/workqueue.c:2609 2 locks held by getty/4824: #0: ffff88802ae3c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfc8/0x1490 drivers/tty/n_tty.c:2201 2 locks held by dhcpcd/5467: #0: ffff8880798a5c10 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:802 [inline] #0: ffff8880798a5c10 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: __sock_release+0x86/0x270 net/socket.c:658 #1: ffffffff8d7bc478 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:293 [inline] #1: ffffffff8d7bc478 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x6b5/0x800 kernel/rcu/tree_exp.h:996 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.8.0-rc1-next-20240124-syzkaller-g8bf1262c53f5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf86/0x1210 kernel/hung_task.c:379 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4506 Comm: klogd Not tainted 6.8.0-rc1-next-20240124-syzkaller-g8bf1262c53f5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 RIP: 0010:__sanitizer_cov_trace_pc+0x33/0x60 kernel/kcov.c:207 Code: 96 77 7e 65 8b 05 85 96 77 7e a9 00 01 ff 00 48 8b 34 24 74 0f f6 c4 01 74 35 8b 82 fc 15 00 00 85 c0 74 2b 8b 82 d8 15 00 00 <83> f8 02 75 20 48 8b 8a e0 15 00 00 8b 92 dc 15 00 00 48 8b 01 48 RSP: 0018:ffffc900031bf4d0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffc900031bf558 RCX: ffffffff813c0726 RDX: ffff88806a001dc0 RSI: ffffffff813c0738 RDI: 0000000000000006 RBP: 0000000000000001 R08: 0000000000000006 R09: ffffffff81e633c2 R10: ffffffff81000000 R11: 0000000000000001 R12: ffffffff81e633c2 R13: 0000000000000000 R14: ffffc900031bf618 R15: ffffc900031bf58d FS: 00007f7e4b522380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000556d618b9680 CR3: 000000006a954000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: orc_find arch/x86/kernel/unwind_orc.c:206 [inline] unwind_next_frame+0x1e8/0x2390 arch/x86/kernel/unwind_orc.c:494 arch_stack_walk+0x100/0x170 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:314 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3814 [inline] slab_alloc_node mm/slub.c:3861 [inline] kmem_cache_alloc_node+0x177/0x350 mm/slub.c:3904 __alloc_skb+0x28b/0x330 net/core/skbuff.c:641 alloc_skb include/linux/skbuff.h:1296 [inline] alloc_skb_with_frags+0xe4/0x710 net/core/skbuff.c:6394 sock_alloc_send_pskb+0x7e5/0x970 net/core/sock.c:2794 unix_dgram_sendmsg+0x464/0x1cb0 net/unix/af_unix.c:1974 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x47f/0x4e0 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [inline] __se_sys_sendto net/socket.c:2199 [inline] __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2199 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7f7e4b6849b5 Code: 8b 44 24 08 48 83 c4 28 48 98 c3 48 98 c3 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 26 45 31 c9 45 31 c0 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 7a 48 8b 15 44 c4 0c 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffd5d001238 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f7e4b6849b5 RDX: 0000000000000048 RSI: 00005594df6a02c0 RDI: 0000000000000003 RBP: 00005594df69b910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000246 R12: 0000000000000013 R13: 00007f7e4b812212 R14: 00007ffd5d001338 R15: 0000000000000000