INFO: task syz-executor.2:5090 blocked for more than 143 seconds. Not tainted 6.8.0-rc5-syzkaller-00002-gfca7526b7d89 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.2 state:D stack:19248 pid:5090 tgid:5090 ppid:1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5400 [inline] __schedule+0x177f/0x49a0 kernel/sched/core.c:6727 __schedule_loop kernel/sched/core.c:6802 [inline] schedule+0x149/0x260 kernel/sched/core.c:6817 schedule_timeout+0xb0/0x310 kernel/time/timer.c:2159 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common kernel/sched/completion.c:116 [inline] wait_for_common kernel/sched/completion.c:127 [inline] wait_for_completion+0x354/0x620 kernel/sched/completion.c:148 btrfs_qgroup_wait_for_completion+0x92/0xc0 fs/btrfs/qgroup.c:3849 close_ctree+0x118/0xd40 fs/btrfs/disk-io.c:4254 generic_shutdown_super+0x136/0x2d0 fs/super.c:646 kill_anon_super+0x3b/0x70 fs/super.c:1230 btrfs_kill_super+0x41/0x50 fs/btrfs/super.c:2093 deactivate_locked_super+0xc4/0x130 fs/super.c:477 cleanup_mnt+0x426/0x4c0 fs/namespace.c:1267 task_work_run+0x24e/0x310 kernel/task_work.c:180 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:108 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline] syscall_exit_to_user_mode+0x167/0x370 kernel/entry/common.c:212 do_syscall_64+0x108/0x240 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x6f/0x77 RIP: 0033:0x7f454427f0d7 RSP: 002b:00007ffcad672dd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f454427f0d7 RDX: 0000000000000000 RSI: 000000000000000a RDI: 00007ffcad672e90 RBP: 00007ffcad672e90 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffcad673f50 R13: 00007f45442c93b9 R14: 000000000024503b R15: 0000000000000009 Showing all locks held in the system: 1 lock held by khungtaskd/29: #0: ffffffff8e130c60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #0: ffffffff8e130c60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #0: ffffffff8e130c60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614 2 locks held by klogd/4499: 2 locks held by getty/4815: #0: ffff88802b5460a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002efe2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b4/0x1e10 drivers/tty/n_tty.c:2201 1 lock held by syz-executor.2/5090: #0: ffff8880347740e0 (&type->s_umount_key#58){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline] #0: ffff8880347740e0 (&type->s_umount_key#58){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff8880347740e0 (&type->s_umount_key#58){++++}-{3:3}, at: deactivate_super+0xb5/0xf0 fs/super.c:509 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.8.0-rc5-syzkaller-00002-gfca7526b7d89 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x198/0x320 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+0xfaf/0xff0 kernel/hung_task.c:379 kthread+0x2ef/0x390 kernel/kthread.c:388 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4499 Comm: klogd Not tainted 6.8.0-rc5-syzkaller-00002-gfca7526b7d89 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:173 [inline] RIP: 0010:write_comp_data kernel/kcov.c:236 [inline] RIP: 0010:__sanitizer_cov_trace_switch+0x9c/0x120 kernel/kcov.c:341 Code: 00 00 00 4d 85 d2 0f 84 8a 00 00 00 4c 8b 4c 24 20 65 4c 8b 1d 85 4c 70 7e 31 d2 eb 08 48 ff c2 49 39 d2 74 71 4c 8b 74 d6 10 <65> 8b 05 75 4c 70 7e a9 00 01 ff 00 74 11 a9 00 01 00 00 74 de 41 RSP: 0018:ffffc90003177260 EFLAGS: 00000246 RAX: 0000000000000003 RBX: 0000000000000000 RCX: ffff88807be69dc0 RDX: 0000000000000000 RSI: ffffffff8dfa0200 RDI: 0000000000000005 RBP: 0000000000000005 R08: 0000000000000005 R09: ffffffff81405513 R10: 0000000000000008 R11: ffff88807be69dc0 R12: ffffffff8f9bf1e4 R13: dffffc0000000000 R14: 0000000000000002 R15: 1ffff9200062ee6c FS: 00007fa71af71380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c01127da90 CR3: 000000007bf3c000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: unwind_next_frame+0x7c3/0x29e0 arch/x86/kernel/unwind_orc.c:515 arch_stack_walk+0x150/0x1b0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x117/0x1d0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:314 [inline] __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3813 [inline] slab_alloc_node mm/slub.c:3860 [inline] kmem_cache_alloc_node+0x18f/0x380 mm/slub.c:3903 __alloc_skb+0x181/0x420 net/core/skbuff.c:641 alloc_skb include/linux/skbuff.h:1296 [inline] alloc_skb_with_frags+0xc3/0x780 net/core/skbuff.c:6394 sock_alloc_send_pskb+0x919/0xa60 net/core/sock.c:2784 unix_dgram_sendmsg+0x696/0x2200 net/unix/af_unix.c:1972 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:745 __sys_sendto+0x3a4/0x4f0 net/socket.c:2191 __do_sys_sendto net/socket.c:2203 [inline] __se_sys_sendto net/socket.c:2199 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2199 do_syscall_64+0xf9/0x240 entry_SYSCALL_64_after_hwframe+0x6f/0x77 RIP: 0033:0x7fa71b0d39b5 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:00007ffd186e0a38 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fa71b0d39b5 RDX: 000000000000004e RSI: 00005577d71640a0 RDI: 0000000000000003 RBP: 00005577d715c910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000246 R12: 0000000000000013 R13: 00007fa71b261212 R14: 00007ffd186e0b38 R15: 0000000000000000