INFO: task syz.1.23:6154 blocked for more than 143 seconds. Not tainted 6.15.0-rc5-syzkaller-00204-g0e1329d4045c #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.23 state:D stack:28952 pid:6154 tgid:6102 ppid:5829 task_flags:0x400040 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x168f/0x4c70 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1176 __down_write_common kernel/locking/rwsem.c:1304 [inline] __down_write kernel/locking/rwsem.c:1313 [inline] down_write_nested+0x1b5/0x200 kernel/locking/rwsem.c:1694 inode_lock_nested include/linux/fs.h:902 [inline] filename_create+0x1f9/0x470 fs/namei.c:4132 do_mkdirat+0xa0/0x590 fs/namei.c:4384 __do_sys_mkdir fs/namei.c:4414 [inline] __se_sys_mkdir fs/namei.c:4412 [inline] __x64_sys_mkdir+0x6c/0x80 fs/namei.c:4412 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f94c018e969 RSP: 002b:00007f94c106c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 00007f94c03b6080 RCX: 00007f94c018e969 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000100 RBP: 00007f94c0210ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f94c03b6080 R15: 00007ffcfb30e7b8 INFO: task syz.1.23:6155 blocked for more than 144 seconds. Not tainted 6.15.0-rc5-syzkaller-00204-g0e1329d4045c #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.23 state:D stack:28952 pid:6155 tgid:6102 ppid:5829 task_flags:0x400040 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x168f/0x4c70 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1176 __down_write_common kernel/locking/rwsem.c:1304 [inline] __down_write kernel/locking/rwsem.c:1313 [inline] down_write_nested+0x1b5/0x200 kernel/locking/rwsem.c:1694 inode_lock_nested include/linux/fs.h:902 [inline] lock_rename fs/namei.c:3265 [inline] do_renameat2+0x3dd/0xc50 fs/namei.c:5216 __do_sys_rename fs/namei.c:5317 [inline] __se_sys_rename fs/namei.c:5315 [inline] __x64_sys_rename+0x82/0x90 fs/namei.c:5315 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f94c018e969 RSP: 002b:00007f94c104b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 RAX: ffffffffffffffda RBX: 00007f94c03b6160 RCX: 00007f94c018e969 RDX: 0000000000000000 RSI: 00002000000000c0 RDI: 0000200000000600 RBP: 00007f94c0210ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f94c03b6160 R15: 00007ffcfb30e7b8 Showing all locks held in the system: 1 lock held by pool_workqueue_/3: #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline] #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b7/0x730 kernel/rcu/tree_exp.h:998 1 lock held by khungtaskd/31: #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764 5 locks held by kworker/u8:5/1076: 2 locks held by getty/5584: #0: ffff888030f350a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002ffe2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 4 locks held by syz.1.23/6103: #0: ffff88805c236420 (sb_writers#20){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556 #1: ffff8880581308e0 (&sb->s_type->i_mutex_key#26/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:902 [inline] #1: ffff8880581308e0 (&sb->s_type->i_mutex_key#26/1){+.+.}-{4:4}, at: filename_create+0x1f9/0x470 fs/namei.c:4132 #2: ffff888055704228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:161 [inline] #2: ffff888055704228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:253 [inline] #2: ffff888055704228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: bch2_trans_srcu_lock+0xaf/0x220 fs/bcachefs/btree_iter.c:3202 #3: ffff888055726590 (&c->gc_lock){.+.+}-{4:4}, at: bch2_btree_update_start+0x68f/0x14c0 fs/bcachefs/btree_update_interior.c:1179 2 locks held by syz.1.23/6154: #0: ffff88805c236420 (sb_writers#20){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556 #1: ffff8880581308e0 (&sb->s_type->i_mutex_key#26/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:902 [inline] #1: ffff8880581308e0 (&sb->s_type->i_mutex_key#26/1){+.+.}-{4:4}, at: filename_create+0x1f9/0x470 fs/namei.c:4132 2 locks held by syz.1.23/6155: #0: ffff88805c236420 (sb_writers#20){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556 #1: ffff8880581308e0 (&sb->s_type->i_mutex_key#26/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:902 [inline] #1: ffff8880581308e0 (&sb->s_type->i_mutex_key#26/1){+.+.}-{4:4}, at: lock_rename fs/namei.c:3265 [inline] #1: ffff8880581308e0 (&sb->s_type->i_mutex_key#26/1){+.+.}-{4:4}, at: do_renameat2+0x3dd/0xc50 fs/namei.c:5216 3 locks held by bch-copygc/loop/6148: 1 lock held by syz-executor/6348: #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline] #0: ffffffff8df41338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b7/0x730 kernel/rcu/tree_exp.h:998 4 locks held by dhcpcd-run-hook/8509: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc5-syzkaller-00204-g0e1329d4045c #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:437 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 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: 6348 Comm: syz-executor Not tainted 6.15.0-rc5-syzkaller-00204-g0e1329d4045c #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:409 Code: e8 8e 2b 89 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 5f fa e8 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07 RSP: 0018:ffffc90003eff370 EFLAGS: 00000002 RAX: 1ffffffff3362f00 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020 RBP: ffffffff99b17c10 R08: ffff8880240f8237 R09: 1ffff1100481f046 R10: dffffc0000000000 R11: ffffffff8536a360 R12: dffffc0000000000 R13: 0000000000000000 R14: ffffffff99b17980 R15: 0000000000000000 FS: 0000555557515500(0000) GS:ffff888126100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f09f4ceb210 CR3: 000000007f202000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_in drivers/tty/serial/8250/8250.h:137 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline] wait_for_lsr+0x19e/0x2f0 drivers/tty/serial/8250/8250_port.c:2098 fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3348 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3371 [inline] serial8250_console_write+0x134c/0x1ba0 drivers/tty/serial/8250/8250_port.c:3456 console_emit_next_record kernel/printk/printk.c:3138 [inline] console_flush_all+0x725/0xc40 kernel/printk/printk.c:3226 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline] console_unlock+0xc4/0x270 kernel/printk/printk.c:3325 vprintk_emit+0x5b7/0x7a0 kernel/printk/printk.c:2450 bch2_print_maybe_redirect fs/bcachefs/super.c:110 [inline] __bch2_print+0x176/0x220 fs/bcachefs/super.c:129 bch2_fs_read_only+0x19a/0x14c0 fs/bcachefs/super.c:319 __bch2_fs_stop+0x106/0x5a0 fs/bcachefs/super.c:628 generic_shutdown_super+0x132/0x2c0 fs/super.c:642 bch2_kill_sb+0x41/0x50 fs/bcachefs/fs.c:2620 deactivate_locked_super+0xb9/0x130 fs/super.c:473 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1435 task_work_run+0x1d1/0x260 kernel/task_work.c:227 resume_user_mode_work+0x5e/0x80 include/linux/resume_user_mode.h:50 exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x9a/0x120 kernel/entry/common.c:218 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6871d8fc97 Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8 RSP: 002b:00007fffd779fc48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f6871e1089d RCX: 00007f6871d8fc97 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fffd779fd00 RBP: 00007fffd779fd00 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fffd77a0d90 R13: 00007f6871e1089d R14: 000000000004162a R15: 00007fffd77a0dd0