syzbot


INFO: task hung in truncate_inode_partial_folio (3)

Status: auto-obsoleted due to no activity on 2025/10/22 20:14
Subsystems: fs mm
[Documentation on labels]
First crash: 193d, last: 193d
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in truncate_inode_partial_folio fs mm 1 14 418d 638d 0/29 auto-obsoleted due to no activity on 2025/03/11 06:48
upstream INFO: task hung in truncate_inode_partial_folio (2) fs mm 1 1 306d 306d 0/29 auto-obsoleted due to no activity on 2025/07/01 08:09

Sample crash report:
INFO: task syz.3.146:7015 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc7-syzkaller-00034-g25fae0b93d1d #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.146       state:D stack:26952 pid:7015  tgid:7000  ppid:5845   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5397 [inline]
 __schedule+0x16aa/0x4c90 kernel/sched/core.c:6786
 __schedule_loop kernel/sched/core.c:6864 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6879
 io_schedule+0x81/0xe0 kernel/sched/core.c:7724
 folio_wait_bit_common+0x6b0/0xb90 mm/filemap.c:1317
 folio_wait_writeback+0xb0/0x100 mm/page-writeback.c:3126
 truncate_inode_partial_folio+0x194/0xcb0 mm/truncate.c:207
 truncate_inode_pages_range+0x564/0xda0 mm/truncate.c:391
 bchfs_fallocate+0x2f4/0x680 fs/bcachefs/fs-io.c:783
 bch2_fallocate_dispatch+0x28a/0x410 fs/bcachefs/fs-io.c:836
 vfs_fallocate+0x6a0/0x830 fs/open.c:341
 ksys_fallocate fs/open.c:365 [inline]
 __do_sys_fallocate fs/open.c:370 [inline]
 __se_sys_fallocate fs/open.c:368 [inline]
 __x64_sys_fallocate+0xc0/0x110 fs/open.c:368
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f75d0f8e9a9
RSP: 002b:00007f75d1e04038 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f75d11b6080 RCX: 00007f75d0f8e9a9
RDX: 0000000000007fff RSI: 0000000000000010 RDI: 0000000000000005
RBP: 00007f75d1010d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000007c25 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f75d11b6080 R15: 00007ffd41580f58
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
 #0: ffff8880b8639e18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:606
3 locks held by kworker/u8:0/12:
1 lock held by khungtaskd/31:
 #0: ffffffff8e13f0e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13f0e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e13f0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
3 locks held by kworker/u8:7/1321:
2 locks held by kworker/u8:8/2967:
3 locks held by kworker/u8:10/3007:
 #0: ffff8881426eb148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff8881426eb148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc9000bde7bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000bde7bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffff888030e620e0 (&type->s_umount_key#82){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563
1 lock held by udevd/5209:
2 locks held by getty/5600:
 #0: ffff88803538a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000333b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
3 locks held by kworker/0:3/5900:
3 locks held by kworker/1:4/5920:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc9000448fbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000448fbc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffff8880529a6240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x26b/0x3180 drivers/net/netdevsim/fib.c:1490
1 lock held by udevd/6204:
1 lock held by syz.3.146/7001:
 #0: ffff888030e62428 (sb_writers#33){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3096 [inline]
 #0: ffff888030e62428 (sb_writers#33){.+.+}-{0:0}, at: vfs_writev+0x288/0x960 fs/read_write.c:1055
2 locks held by syz.3.146/7015:
 #0: ffff888030e62428 (sb_writers#33){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3096 [inline]
 #0: ffff888030e62428 (sb_writers#33){.+.+}-{0:0}, at: vfs_fallocate+0x62a/0x830 fs/open.c:340
 #1: ffff888079ba9810 (&sb->s_type->i_mutex_key#36){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff888079ba9810 (&sb->s_type->i_mutex_key#36){++++}-{4:4}, at: bch2_fallocate_dispatch+0x10e/0x410 fs/bcachefs/fs-io.c:827
1 lock held by syz-executor/7901:
 #0: ffffffff8e144bf8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline]
 #0: ffffffff8e144bf8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:998
3 locks held by syz-executor/9271:
1 lock held by syz.2.368/9634:
 #0: ffffffff8e144bf8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline]
 #0: ffffffff8e144bf8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:998
4 locks held by syz.5.367/9646:
2 locks held by sed/9705:

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc7-syzkaller-00034-g25fae0b93d1d #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 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:307 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:470
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9271 Comm: syz-executor Not tainted 6.16.0-rc7-syzkaller-00034-g25fae0b93d1d #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:io_serial_out+0x7c/0xc0 drivers/tty/serial/8250/8250_port.c:416
Code: 0c 81 fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 dc f3 e0 fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc90004d3df10 EFLAGS: 00000002
RAX: 0000000000000033 RBX: 0000000000000033 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: ffff888024e08237 R09: 1ffff110049c1046
R10: dffffc0000000000 R11: ffffffff853f18a0 R12: dffffc0000000000
R13: ffffffff99abd885 R14: ffffffff99dc20c0 R15: 0000000000000000
FS:  0000555560ea6500(0000) GS:ffff888125c57000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005561eaa52708 CR3: 00000000312ba000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 serial_port_out include/linux/serial_core.h:798 [inline]
 serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3306 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline]
 serial8250_console_write+0x1410/0x1ba0 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
 dev_vprintk_emit+0x337/0x3f0 drivers/base/core.c:4917
 dev_printk_emit+0xe0/0x130 drivers/base/core.c:4928
 __netdev_printk+0x3d7/0x4d0 net/core/dev.c:12509
 netdev_info+0x10a/0x160 net/core/dev.c:12564
 nsim_udp_tunnel_set_port+0x29b/0x440 drivers/net/netdevsim/udp_tunnels.c:34
 udp_tunnel_nic_device_sync_one net/ipv4/udp_tunnel_nic.c:-1 [inline]
 udp_tunnel_nic_device_sync_by_port net/ipv4/udp_tunnel_nic.c:246 [inline]
 __udp_tunnel_nic_device_sync+0xb05/0x14c0 net/ipv4/udp_tunnel_nic.c:289
 udp_tunnel_nic_device_sync net/ipv4/udp_tunnel_nic.c:312 [inline]
 __udp_tunnel_nic_add_port+0xbd5/0xe50 net/ipv4/udp_tunnel_nic.c:531
 udp_tunnel_nic_add_port include/net/udp_tunnel.h:365 [inline]
 udp_tunnel_notify_add_rx_port+0x296/0x3e0 net/ipv4/udp_tunnel_core.c:143
 geneve_socket_create drivers/net/geneve.c:612 [inline]
 geneve_sock_add+0x55d/0x910 drivers/net/geneve.c:687
 geneve_open+0xd2/0x140 drivers/net/geneve.c:729
 __dev_open+0x46d/0x880 net/core/dev.c:1683
 __dev_change_flags+0x1ea/0x6d0 net/core/dev.c:9458
 netif_change_flags+0x88/0x1a0 net/core/dev.c:9521
 do_setlink+0xc55/0x41c0 net/core/rtnetlink.c:3141
 rtnl_changelink net/core/rtnetlink.c:3759 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3918 [inline]
 rtnl_newlink+0x160b/0x1c70 net/core/rtnetlink.c:4055
 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6944
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x75c/0x8e0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:727
 __sys_sendto+0x3bd/0x520 net/socket.c:2180
 __do_sys_sendto net/socket.c:2187 [inline]
 __se_sys_sendto net/socket.c:2183 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2183
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2797b9083c
Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
RSP: 002b:00007ffd0cb65760 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f27988e4620 RCX: 00007f2797b9083c
RDX: 000000000000002c RSI: 00007f27988e4670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffd0cb657b4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f27988e4670 R15: 0000000000000000
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/24 20:09 upstream 25fae0b93d1d 65d60d73 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in truncate_inode_partial_folio
* Struck through repros no longer work on HEAD.