syzbot


INFO: task hung in start_transaction

Status: upstream: reported on 2024/03/31 10:14
Reported-by: syzbot+afafcee6a1b6d4e6587a@syzkaller.appspotmail.com
First crash: 79d, last: 79d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in start_transaction btrfs C 3 493d 543d 0/1 upstream: reported C repro on 2022/12/23 07:52

Sample crash report:
INFO: task kworker/u4:4:57 blocked for more than 143 seconds.
      Not tainted 6.1.83-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:4    state:D stack:20344 pid:57    ppid:2      flags:0x00004000
Workqueue: btrfs-qgroup-rescan btrfs_work_helper
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 wait_current_trans+0x33a/0x4b0 fs/btrfs/transaction.c:515
 start_transaction+0xb0f/0x1240 fs/btrfs/transaction.c:662
 btrfs_qgroup_rescan_worker+0x1636/0x1ac0 fs/btrfs/qgroup.c:3437
 btrfs_work_helper+0x3ae/0xcf0 fs/btrfs/async-thread.c:280
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:307
 </TASK>
INFO: task kworker/u4:7:4765 blocked for more than 143 seconds.
      Not tainted 6.1.83-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:7    state:D stack:21528 pid:4765  ppid:2      flags:0x00004000
Workqueue: writeback wb_workfn (flush-btrfs-3)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 wait_on_state fs/btrfs/extent-io-tree.c:709 [inline]
 wait_extent_bit+0x423/0x570 fs/btrfs/extent-io-tree.c:742
 lock_extent+0x17a/0x200 fs/btrfs/extent-io-tree.c:1657
 btrfs_invalidate_folio+0x444/0xfa0 fs/btrfs/inode.c:8406
 __extent_writepage+0x5d8/0x1730 fs/btrfs/extent_io.c:2266
 extent_write_cache_pages fs/btrfs/extent_io.c:3196 [inline]
 extent_writepages+0xbe0/0x17a0 fs/btrfs/extent_io.c:3318
 do_writepages+0x3a2/0x670 mm/page-writeback.c:2469
 __writeback_single_inode+0x15d/0x11e0 fs/fs-writeback.c:1612
 writeback_sb_inodes+0xc2b/0x1b20 fs/fs-writeback.c:1903
 wb_writeback+0x49d/0xe10 fs/fs-writeback.c:2077
 wb_do_writeback fs/fs-writeback.c:2220 [inline]
 wb_workfn+0x427/0x1020 fs/fs-writeback.c:2260
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:307
 </TASK>
INFO: task syz-executor.2:4936 blocked for more than 143 seconds.
      Not tainted 6.1.83-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2  state:D stack:22488 pid:4936  ppid:3577   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 wb_wait_for_completion+0x162/0x290 fs/fs-writeback.c:191
 __writeback_inodes_sb_nr+0x2ce/0x370 fs/fs-writeback.c:2653
 try_to_writeback_inodes_sb+0x94/0xb0 fs/fs-writeback.c:2701
 btrfs_start_delalloc_flush fs/btrfs/transaction.c:2099 [inline]
 btrfs_commit_transaction+0xb2f/0x3c70 fs/btrfs/transaction.c:2279
 btrfs_sync_file+0xc60/0x1100 fs/btrfs/file.c:2000
 generic_write_sync include/linux/fs.h:2957 [inline]
 btrfs_do_write_iter+0xd74/0x12f0 fs/btrfs/file.c:1685
 do_iter_write+0x6e6/0xc50 fs/read_write.c:861
 vfs_writev fs/read_write.c:934 [inline]
 do_pwritev+0x216/0x360 fs/read_write.c:1031
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f65f727dda9
RSP: 002b:00007f65f80220c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 00007f65f73abf80 RCX: 00007f65f727dda9
RDX: 0000000000000001 RSI: 0000000020000500 RDI: 0000000000000005
RBP: 00007f65f72ca47a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f65f73abf80 R15: 00007ffc3c86d1c8
 </TASK>
INFO: task syz-executor.2:4970 blocked for more than 143 seconds.
      Not tainted 6.1.83-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2  state:D stack:25432 pid:4970  ppid:3577   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 wait_current_trans+0x33a/0x4b0 fs/btrfs/transaction.c:515
 start_transaction+0xb0f/0x1240 fs/btrfs/transaction.c:662
 clone_copy_inline_extent fs/btrfs/reflink.c:290 [inline]
 btrfs_clone+0x17ab/0x2a00 fs/btrfs/reflink.c:524
 btrfs_clone_files+0x329/0x400 fs/btrfs/reflink.c:766
 btrfs_remap_file_range+0x573/0xe80 fs/btrfs/reflink.c:904
 vfs_copy_file_range+0x11b1/0x1630 fs/read_write.c:1518
 __do_sys_copy_file_range fs/read_write.c:1596 [inline]
 __se_sys_copy_file_range+0x3ea/0x5d0 fs/read_write.c:1559
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f65f727dda9
RSP: 002b:00007f65f80010c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000146
RAX: ffffffffffffffda RBX: 00007f65f73ac050 RCX: 00007f65f727dda9
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f65f72ca47a R08: 0000000000000009 R09: 0000000000000000
R10: 0000000020000640 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f65f73ac050 R15: 00007ffc3c86d1c8
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u4:1/11:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8d12ab10 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:516
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8d12b310 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:516
1 lock held by khungtaskd/28:
 #0: ffffffff8d12a940 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8d12a940 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8d12a940 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6494
3 locks held by kworker/u4:4/57:
 #0: ffff888023023138 ((wq_completion)btrfs-qgroup-rescan){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #1: ffffc90001587d20 ((work_completion)(&work->normal_work)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #2: ffff88805b8ee650 (sb_internal#3){.+.+}-{0:0}, at: btrfs_qgroup_rescan_worker+0x1636/0x1ac0 fs/btrfs/qgroup.c:3437
2 locks held by udevd/3002:
2 locks held by getty/3306:
 #0: ffff8880288a2098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc900031262f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a7/0x1db0 drivers/tty/n_tty.c:2188
5 locks held by kworker/u4:5/3623:
 #0: ffff888012616938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #1: ffffc90004ad7d20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #2: ffffffff8e28cf90 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xf1/0xb60 net/core/net_namespace.c:563
 #3: ffffffff8e2991e8 (rtnl_mutex){+.+.}-{3:3}, at: ip_tunnel_delete_nets+0xc9/0x330 net/ipv4/ip_tunnel.c:1148
 #4: ffffffff8d12ff38 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #4: ffffffff8d12ff38 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x4f0/0x930 kernel/rcu/tree_exp.h:962
3 locks held by kworker/0:14/3827:
2 locks held by kworker/u4:7/4765:
 #0: ffff888142efd138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #1: ffffc9000324fd20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
5 locks held by syz-executor.2/4936:
 #0: ffff88805b8ee460 (sb_writers#14){.+.+}-{0:0}, at: vfs_writev fs/read_write.c:933 [inline]
 #0: ffff88805b8ee460 (sb_writers#14){.+.+}-{0:0}, at: do_pwritev+0x1fa/0x360 fs/read_write.c:1031
 #1: ffff88805b8ee650 (sb_internal#3){.+.+}-{0:0}, at: btrfs_sync_file+0xa56/0x1100 fs/btrfs/file.c:1919
 #2: ffff88805be56328 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0x193/0xd40 fs/btrfs/transaction.c:300
 #3: ffff88805be56350 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0x193/0xd40 fs/btrfs/transaction.c:300
 #4: ffff88805b8ee0e0 (&type->s_umount_key#52){++++}-{3:3}, at: try_to_writeback_inodes_sb+0x1d/0xb0 fs/fs-writeback.c:2698
4 locks held by syz-executor.2/4970:
 #0: ffff88805b8ee460 (sb_writers#14){.+.+}-{0:0}, at: vfs_copy_file_range+0x981/0x1630 fs/read_write.c:1502
 #1: ffff888057e985e0 (&sb->s_type->i_mutex_key#22){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff888057e985e0 (&sb->s_type->i_mutex_key#22){+.+.}-{3:3}, at: btrfs_inode_lock+0x49/0xd0 fs/btrfs/inode.c:155
 #2: ffff888057e98468 (&ei->i_mmap_lock){+.+.}-{3:3}, at: btrfs_inode_lock+0xc1/0xd0 fs/btrfs/inode.c:158
 #3: ffff88805b8ee650 (sb_internal#3){.+.+}-{0:0}, at: clone_copy_inline_extent fs/btrfs/reflink.c:290 [inline]
 #3: ffff88805b8ee650 (sb_internal#3){.+.+}-{0:0}, at: btrfs_clone+0x17ab/0x2a00 fs/btrfs/reflink.c:524
1 lock held by btrfs-transacti/4968:
 #0: ffff88805be547e0 (&fs_info->transaction_kthread_mutex){+.+.}-{3:3}, at: transaction_kthread+0x100/0x4c0 fs/btrfs/disk-io.c:1898
1 lock held by syz-executor.2/5091:
2 locks held by kworker/u4:10/7430:
 #0: ffff888012479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #1: ffffc9000e75fd20 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
1 lock held by udevadm/8756:
6 locks held by syz-executor.1/8758:
2 locks held by syz-executor.4/8775:

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.1.83-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x4e1/0x560 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1b0/0x3f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf88/0xfd0 kernel/hung_task.c:377
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:307
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8775 Comm: syz-executor.4 Not tainted 6.1.83-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:io_serial_out+0x7a/0xb0 drivers/tty/serial/8250/8250_port.c:468
Code: fc 89 e9 41 d3 e7 48 83 c3 40 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 d0 02 31 fd 44 03 3b 44 89 f0 44 89 fa ee <5b> 41 5c 41 5e 41 5f 5d c3 89 e9 80 e1 07 38 c1 7c ab 48 89 ef e8
RSP: 0018:ffffc90012b2ea30 EFLAGS: 00000002
RAX: 000000000000005b RBX: ffffffff920184a0 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000012044 RDI: 0000000000012045
RBP: 0000000000000000 R08: ffffffff84b0f767 R09: ffffed1003ea8047
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 0000000000000001 R14: 000000000000005b R15: 00000000000003f8
FS:  00007fdb558926c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdb4b23e000 CR3: 000000005b2da000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 serial8250_console_write+0x11d2/0x1750 drivers/tty/serial/8250/8250_port.c:3451
 call_console_driver kernel/printk/printk.c:1971 [inline]
 console_emit_next_record+0xbb4/0x1000 kernel/printk/printk.c:2771
 console_unlock+0x278/0x7c0 kernel/printk/printk.c:2900
 vprintk_emit+0x523/0x740 kernel/printk/printk.c:2297
 _printk+0xd1/0x111 kernel/printk/printk.c:2322
 set_capacity_and_notify+0x2b0/0x340 block/genhd.c:91
 loop_set_size+0x44/0xa0 drivers/block/loop.c:235
 loop_configure+0xd1d/0x1270 drivers/block/loop.c:1098
 lo_ioctl+0x882/0x2010
 blkdev_ioctl+0x3a9/0x760 block/ioctl.c:618
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fdb54a7db0b
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007fdb55891e50 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fdb54a7db0b
RDX: 0000000000000003 RSI: 0000000000004c00 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000046c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007fdb55891f80 R14: 00007fdb55891f40 R15: 00007fdb4b1ff000
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/31 10:13 linux-6.1.y e5cd595e23c1 6baf5069 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in start_transaction
* Struck through repros no longer work on HEAD.