INFO: task syz.0.734:12564 blocked for more than 143 seconds. Not tainted 6.15.0-rc4-syzkaller-00052-g4f79eaa2ceac #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.734 state:D stack:28952 pid:12564 tgid:12523 ppid:5827 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: 0033:0x7fe36b78e969 RSP: 002b:00007fe36c544038 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 RAX: ffffffffffffffda RBX: 00007fe36b9b6080 RCX: 00007fe36b78e969 RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000200000000000 RBP: 00007fe36b810ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007fe36b9b6080 R15: 00007fffe13a2e58 INFO: task syz.0.734:12565 blocked for more than 144 seconds. Not tainted 6.15.0-rc4-syzkaller-00052-g4f79eaa2ceac #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.734 state:D stack:27928 pid:12565 tgid:12523 ppid:5827 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+0x1ab/0x1f0 kernel/locking/rwsem.c:1578 inode_lock include/linux/fs.h:867 [inline] open_last_lookups fs/namei.c:3797 [inline] path_openat+0x8da/0x3830 fs/namei.c:4036 do_filp_open+0x1fa/0x410 fs/namei.c:4066 do_sys_openat2+0x121/0x1c0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_openat fs/open.c:1460 [inline] __se_sys_openat fs/open.c:1455 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1455 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: 0033:0x7fe36b78e969 RSP: 002b:00007fe36c523038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fe36b9b6160 RCX: 00007fe36b78e969 RDX: 0000000000008042 RSI: 00002000000000c0 RDI: ffffffffffffff9c RBP: 00007fe36b810ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fe36b9b6160 R15: 00007fffe13a2e58 Showing all locks held in the system: 1 lock held by pool_workqueue_/3: #0: ffffffff8dde2e28 (wq_pool_mutex){+.+.}-{4:4}, at: pwq_release_workfn+0x3dc/0x870 kernel/workqueue.c:5091 8 locks held by kworker/u8:0/12: 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 3 locks held by kworker/u8:6/1100: #0: ffff8880b89399d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605 #1: ffff8880b8923b08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x39e/0x6d0 kernel/sched/psi.c:987 #2: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #2: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #2: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1155 [inline] #2: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0xa5/0x2390 arch/x86/kernel/unwind_orc.c:479 2 locks held by getty/5573: #0: ffff888034b1a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002ff62f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 2 locks held by udevd/6486: 5 locks held by syz.0.734/12524: #0: ffff8880710da420 (sb_writers#22){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556 #1: ffff8880763b1078 (&sb->s_type->i_mutex_key#30){++++}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline] #1: ffff8880763b1078 (&sb->s_type->i_mutex_key#30){++++}-{4:4}, at: open_last_lookups fs/namei.c:3797 [inline] #1: ffff8880763b1078 (&sb->s_type->i_mutex_key#30){++++}-{4:4}, at: path_openat+0x8da/0x3830 fs/namei.c:4036 #2: ffff8880763b1460 (&inode->ei_update_lock){+.+.}-{4:4}, at: __bch2_create+0x2f2/0xb90 fs/bcachefs/fs.c:567 #3: ffff888067a84228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:161 [inline] #3: ffff888067a84228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:253 [inline] #3: ffff888067a84228 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x806/0xda0 fs/bcachefs/btree_iter.c:3385 #4: ffff888067aa6590 (&c->gc_lock){++++}-{4:4}, at: bch2_btree_update_start+0x68f/0x14c0 fs/bcachefs/btree_update_interior.c:1179 2 locks held by syz.0.734/12564: #0: ffff8880710da420 (sb_writers#22){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556 #1: ffff8880763b1078 (&sb->s_type->i_mutex_key#30/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:902 [inline] #1: ffff8880763b1078 (&sb->s_type->i_mutex_key#30/1){+.+.}-{4:4}, at: lock_rename fs/namei.c:3265 [inline] #1: ffff8880763b1078 (&sb->s_type->i_mutex_key#30/1){+.+.}-{4:4}, at: do_renameat2+0x3dd/0xc50 fs/namei.c:5216 2 locks held by syz.0.734/12565: #0: ffff8880710da420 (sb_writers#22){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556 #1: ffff8880763b1078 (&sb->s_type->i_mutex_key#30){++++}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline] #1: ffff8880763b1078 (&sb->s_type->i_mutex_key#30){++++}-{4:4}, at: open_last_lookups fs/namei.c:3797 [inline] #1: ffff8880763b1078 (&sb->s_type->i_mutex_key#30){++++}-{4:4}, at: path_openat+0x8da/0x3830 fs/namei.c:4036 1 lock held by bch-copygc/loop/12557: 1 lock held by syz-executor/14516: #0: ffff8880274600e0 (&type->s_umount_key#61){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff8880274600e0 (&type->s_umount_key#61){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff8880274600e0 (&type->s_umount_key#61){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 2 locks held by syz.2.1046/15328: 6 locks held by syz.1.1047/15334: #0: ffff888148392420 (sb_writers#13){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3041 [inline] #0: ffff888148392420 (sb_writers#13){.+.+}-{0:0}, at: vfs_write+0x211/0xa90 fs/read_write.c:680 #1: ffff888148392610 (sb_internal#2){.+.+}-{0:0}, at: btrfs_sync_file+0xbf5/0x1130 fs/btrfs/file.c:1646 #2: ffff88806d5364d0 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0x41b/0xd70 fs/btrfs/transaction.c:296 #3: ffff88806d5364f8 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0x41b/0xd70 fs/btrfs/transaction.c:296 #4: ffff88806d534730 (&fs_info->tree_log_mutex){+.+.}-{4:4}, at: btrfs_sync_log+0x1d79/0x27b0 fs/btrfs/tree-log.c:3144 #5: ffff8880777ab8d8 (&fs_devs->device_list_mutex){+.+.}-{4:4}, at: write_all_supers+0x12ab/0x3d10 fs/btrfs/disk-io.c:4102 1 lock held by syz.8.1048/15344: 4 locks held by dhcpcd-run-hook/15398: #0: ffff8880b88399d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605 #1: ffff8880b8823b08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x39e/0x6d0 kernel/sched/psi.c:987 #2: ffff8880771062b8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] #2: ffff8880771062b8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: __pte_offset_map_lock+0x106/0x1e0 mm/pgtable-generic.c:402 #3: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #3: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #3: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: page_table_check_set+0x16b/0x710 mm/page_table_check.c:112 1 lock held by udevadm/15401: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc4-syzkaller-00052-g4f79eaa2ceac #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 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: 12557 Comm: bch-copygc/loop Not tainted 6.15.0-rc4-syzkaller-00052-g4f79eaa2ceac #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 RIP: 0010:__rcu_read_unlock+0x71/0xe0 kernel/rcu/tree_plugin.h:445 Code: e8 03 42 0f b6 04 38 84 c0 75 66 41 83 3e 00 75 27 43 0f b6 04 3c 84 c0 75 41 8b 03 3d 00 00 00 40 73 0f 5b 41 5c 41 5d 41 5e <41> 5f c3 cc cc cc cc cc 90 0f 0b 90 eb eb e8 6c 00 00 00 eb d2 89 RSP: 0000:ffffc90004346f88 EFLAGS: 00000287 RAX: 0000000000000000 RBX: ffffffff90101601 RCX: 6dc62053a8f98300 RDX: 0000000000000000 RSI: ffffffff8d9208e6 RDI: ffff888028945a00 RBP: dffffc0000000000 R08: ffffc900043471a0 R09: 0000000000000000 R10: ffffc900043470b8 R11: fffff52000868e19 R12: ffffc900043471b0 R13: ffffc90004340000 R14: ffffc90004347068 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888126100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd675207000 CR3: 000000006acfe000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_unlock include/linux/rcupdate.h:873 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x19ae/0x2390 arch/x86/kernel/unwind_orc.c:680 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2398 [inline] slab_free mm/slub.c:4656 [inline] kfree+0x193/0x440 mm/slub.c:4855 move_buckets_wait+0x1024/0x12d0 fs/bcachefs/movinggc.c:134 bch2_copygc_get_buckets fs/bcachefs/movinggc.c:158 [inline] bch2_copygc+0x281/0x3cf0 fs/bcachefs/movinggc.c:221 bch2_copygc_thread+0x8c9/0xd40 fs/bcachefs/movinggc.c:405 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