syzbot


INFO: task hung in nilfs_segctor_thread (3)

Status: upstream: reported on 2024/12/03 18:16
Reported-by: syzbot+ed9c868b4a9cf0c11ec3@syzkaller.appspotmail.com
First crash: 17d, last: 17d
Similar bugs (8)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in nilfs_segctor_thread nilfs2 C 41 676d 777d 0/1 upstream: reported C repro on 2022/11/05 03:06
linux-5.15 INFO: task hung in nilfs_segctor_thread (2) 2 143d 223d 0/3 auto-obsoleted due to no activity on 2024/11/07 22:53
upstream INFO: task hung in nilfs_segctor_thread (3) nilfs 138 129d 154d 0/28 auto-obsoleted due to no activity on 2024/10/22 18:08
upstream INFO: task hung in nilfs_segctor_thread nilfs C error 94 598d 772d 22/28 fixed on 2023/06/08 14:41
linux-5.15 INFO: task hung in nilfs_segctor_thread 3 609d 621d 0/3 auto-obsoleted due to no activity on 2023/08/20 05:29
linux-4.14 INFO: task hung in nilfs_segctor_thread nilfs2 C 1 674d 674d 0/1 upstream: reported C repro on 2023/02/16 07:03
upstream INFO: task hung in nilfs_segctor_thread (2) nilfs C inconclusive 98 196d 306d 26/28 fixed on 2024/07/09 19:14
linux-6.1 INFO: task hung in nilfs_segctor_thread 40 78d 223d 0/3 auto-obsoleted due to no activity on 2024/12/12 18:46

Sample crash report:
INFO: task segctord:4764 blocked for more than 143 seconds.
      Not tainted 5.15.173-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:segctord        state:D stack:    0 pid: 4764 ppid:     2 flags:0x00000008
Call trace:
 __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0xf10/0x1e48 kernel/sched/core.c:6373
 schedule+0x11c/0x1c8 kernel/sched/core.c:6456
 rwsem_down_write_slowpath+0xd94/0x17e0 kernel/locking/rwsem.c:1165
 __down_write_common kernel/locking/rwsem.c:1292 [inline]
 __down_write kernel/locking/rwsem.c:1301 [inline]
 down_write+0xe8/0x12c kernel/locking/rwsem.c:1552
 nilfs_transaction_lock+0x150/0x3d0 fs/nilfs2/segment.c:357
 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2560 [inline]
 nilfs_segctor_thread+0x3dc/0xe60 fs/nilfs2/segment.c:2645
 kthread+0x37c/0x45c kernel/kthread.c:334
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffff800014d322e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:311
4 locks held by kworker/u4:4/424:
3 locks held by kworker/0:3/1972:
 #0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
 #1: ffff8000254e7c00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
 #2: ffff0000e5a55240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x274/0x33c4 drivers/net/netdevsim/fib.c:1480
1 lock held by udevd/3643:
2 locks held by getty/3789:
 #0: ffff0000d3f38098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x40/0x50 drivers/tty/tty_ldsem.c:340
 #1: ffff80001d62e2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1204 drivers/tty/n_tty.c:2158
2 locks held by kworker/u4:11/4339:
 #0: ffff0000c0029138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
 #1: ffff8000205c7c00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
2 locks held by kworker/0:9/4386:
 #0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
 #1: ffff800020787c00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
2 locks held by kworker/1:11/4759:
 #0: ffff0000c0021938 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
 #1: ffff800020347c00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
2 locks held by syz.4.154/4761:
1 lock held by segctord/4764:
 #0: ffff0000cdf1a2a0 (&nilfs->ns_segctor_sem){++++}-{3:3}, at: nilfs_transaction_lock+0x150/0x3d0 fs/nilfs2/segment.c:357
3 locks held by kworker/0:11/5156:
 #0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
 #1: ffff800020f07c00 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
 #2: ffff0000e609f400 (&nsim_dev->port_list_lock#2){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x60/0x90c drivers/net/netdevsim/dev.c:757
3 locks held by kworker/u4:15/5831:
2 locks held by syz-executor/6337:
7 locks held by syz-executor/7100:
 #0: ffff0000d4582460 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x228/0xb44 fs/read_write.c:590
 #1: ffff0000e64cb488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1c8/0x48c fs/kernfs/file.c:287
 #2: ffff0000ce590ae8 (kn->active#230){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x1e4/0x48c fs/kernfs/file.c:288
 #3: ffff8000162711a8 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xec/0x3bc drivers/net/netdevsim/bus.c:344
 #4: ffff0000e609b178 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #4: ffff0000e609b178 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1044 [inline]
 #4: ffff0000e609b178 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xbc/0x6ac drivers/base/dd.c:1259
 #5: ffff0000e609f400 (&nsim_dev->port_list_lock#2){+.+.}-{3:3}, at: nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1359 [inline]
 #5: ffff0000e609f400 (&nsim_dev->port_list_lock#2){+.+.}-{3:3}, at: nsim_dev_reload_destroy+0xfc/0x214 drivers/net/netdevsim/dev.c:1561
 #6: ffff800016ca2c28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:72
1 lock held by syz-executor/7161:
 #0: ffff800016ca2c28 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffff800016ca2c28 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0xa2c/0xdac net/core/rtnetlink.c:5644
2 locks held by syz.4.457/7175:
2 locks held by dhcpcd/7205:
 #0: ffff0000de3fd010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
 #0: ffff0000de3fd010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:648 [inline]
 #0: ffff0000de3fd010 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x80/0x1fc net/socket.c:1336
 #1: ffff800014d368e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #1: ffff800014d368e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2f0/0x660 kernel/rcu/tree_exp.h:845

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Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/03 18:16 linux-5.15.y 0a51d2d4527b 578925bc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in nilfs_segctor_thread
* Struck through repros no longer work on HEAD.