INFO: task syz-executor814:5054 blocked for more than 143 seconds. Not tainted 6.8.0-rc1-syzkaller-00311-g3a5879d495b2 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor814 state:D stack:27648 pid:5054 tgid:5054 ppid:5053 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5400 [inline] __schedule+0xf12/0x5c00 kernel/sched/core.c:6727 __schedule_loop kernel/sched/core.c:6802 [inline] schedule+0xe9/0x270 kernel/sched/core.c:6817 schedule_timeout+0x257/0x290 kernel/time/timer.c:2159 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common+0x3e0/0x5f0 kernel/sched/completion.c:116 __flush_workqueue+0x3e0/0x1340 kernel/workqueue.c:3198 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+0x2f3/0x760 block/ioctl.c:634 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+0x18f/0x210 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd3/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f9e6bf21879 RSP: 002b:00007fffbf638dc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9e6bf21879 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 00007f9e6bf945f0 R08: 0000000000000006 R09: 0000000000000006 R10: 0000000000000006 R11: 0000000000000246 R12: 0000000000000001 R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001 Showing all locks held in the system: 1 lock held by khungtaskd/29: #0: ffffffff8d1a9120 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #0: ffffffff8d1a9120 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #0: ffffffff8d1a9120 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x75/0x340 kernel/locking/lockdep.c:6614 2 locks held by kworker/u4:12/2912: 2 locks held by kworker/u5:1/4446: #0: ffff88801e6d4538 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x789/0x15d0 kernel/workqueue.c:2608 #1: ffffc9000d6d7d80 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7eb/0x15d0 kernel/workqueue.c:2609 2 locks held by getty/4805: #0: ffff888029a370a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900015b02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfc6/0x1490 drivers/tty/n_tty.c:2201 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.8.0-rc1-syzkaller-00311-g3a5879d495b2 #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+0x277/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x299/0x300 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+0xf87/0x1210 kernel/hung_task.c:379 kthread+0x2c6/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4492 Comm: klogd Not tainted 6.8.0-rc1-syzkaller-00311-g3a5879d495b2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline] RIP: 0010:unwind_next_frame+0x310/0x2390 arch/x86/kernel/unwind_orc.c:494 Code: 76 c4 4c 00 8b 54 24 34 48 8d 14 52 48 8d 94 12 4c 93 bf 8f 48 81 fa ac 1e 76 90 0f 87 e8 09 00 00 e8 54 c4 4c 00 8b 54 24 34 <4c> 89 e1 4c 89 ee 8b 44 24 28 4a 8d 3c b5 0c e1 45 8f 29 c2 e8 c7 RSP: 0018:ffffc90003447458 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffffc900034474d8 RCX: ffffffff813a4741 RDX: 0000000000176cb7 RSI: ffffffff813a481c RDI: ffffffff9093e00c RBP: 0000000000000001 R08: 0000000000000004 R09: 0000000000077057 R10: 000000000009c000 R11: 0000000000000200 R12: ffffffff887057e4 R13: ffffffff904c1f90 R14: 0000000000176cb6 R15: ffffc9000344750d FS: 00007f37378a6380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000564465ab3680 CR3: 000000002b915000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_stack_walk+0xfa/0x170 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x96/0xd0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x50 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:372 [inline] __kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:389 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slub.c:3981 [inline] __kmalloc_node_track_caller+0x219/0x460 mm/slub.c:4001 kmalloc_reserve+0xef/0x260 net/core/skbuff.c:582 __alloc_skb+0x12b/0x330 net/core/skbuff.c:651 alloc_skb include/linux/skbuff.h:1296 [inline] alloc_skb_with_frags+0xe4/0x710 net/core/skbuff.c:6394 sock_alloc_send_pskb+0x7e4/0x970 net/core/sock.c:2784 unix_dgram_sendmsg+0x464/0x1ca0 net/unix/af_unix.c:1974 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0xd5/0x180 net/socket.c:745 __sys_sendto+0x225/0x310 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [inline] __se_sys_sendto net/socket.c:2199 [inline] __x64_sys_sendto+0xe0/0x1b0 net/socket.c:2199 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd3/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f3737a089b5 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:00007ffd1222db88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3737a089b5 RDX: 0000000000000088 RSI: 0000557fe5423880 RDI: 0000000000000003 RBP: 0000557fe541d2c0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000246 R12: 0000000000000013 R13: 00007f3737b96212 R14: 00007ffd1222dc88 R15: 0000000000000000 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 2.127 msecs