syzbot

INFO: task syz.1.2040:13930 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.2040      state:D stack:27304 pid:13930 tgid:13905 ppid:13110  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
 rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185
 __down_write_common kernel/locking/rwsem.c:1317 [inline]
 __down_write kernel/locking/rwsem.c:1326 [inline]
 down_write_nested+0x1b5/0x200 kernel/locking/rwsem.c:1707
 inode_lock_nested include/linux/fs.h:1025 [inline]
 do_unlinkat+0x1c7/0x560 fs/namei.c:4724
 __do_sys_unlink fs/namei.c:4783 [inline]
 __se_sys_unlink fs/namei.c:4781 [inline]
 __x64_sys_unlink+0x47/0x50 fs/namei.c:4781
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa49e18efc9
RSP: 002b:00007fa49f01e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00007fa49e3e6090 RCX: 00007fa49e18efc9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000000
RBP: 00007fa49e211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa49e3e6128 R14: 00007fa49e3e6090 R15: 00007ffd428945b8
 </TASK>
INFO: task syz.1.2040:13934 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.2040      state:D stack:28904 pid:13934 tgid:13905 ppid:13110  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
 rwsem_down_read_slowpath+0x5fd/0x8f0 kernel/locking/rwsem.c:1086
 __down_read_common kernel/locking/rwsem.c:1261 [inline]
 __down_read kernel/locking/rwsem.c:1274 [inline]
 down_read+0x98/0x2e0 kernel/locking/rwsem.c:1539
 inode_lock_shared include/linux/fs.h:995 [inline]
 lookup_slow+0x46/0x70 fs/namei.c:1832
 walk_component+0x2d2/0x400 fs/namei.c:2151
 lookup_last fs/namei.c:2652 [inline]
 path_lookupat+0x163/0x430 fs/namei.c:2676
 filename_lookup+0x212/0x570 fs/namei.c:2705
 user_path_at+0x3a/0x60 fs/namei.c:3215
 __do_sys_fspick fs/fsopen.c:186 [inline]
 __se_sys_fspick+0x10f/0x3d0 fs/fsopen.c:163
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa49e18efc9
RSP: 002b:00007fa49effd038 EFLAGS: 00000246 ORIG_RAX: 00000000000001b1
RAX: ffffffffffffffda RBX: 00007fa49e3e6180 RCX: 00007fa49e18efc9
RDX: 0000000000000000 RSI: 0000200000000740 RDI: 000000000000000a
RBP: 00007fa49e211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa49e3e6218 R14: 00007fa49e3e6180 R15: 00007ffd428945b8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8df3d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df3d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
 #0: ffffffff8df3d2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by khugepaged/38:
3 locks held by kworker/u8:7/2992:
 #0: ffff88801f2ed148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
 #0: ffff88801f2ed148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
 #1: ffffc9000b9cfba0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
 #1: ffffc9000b9cfba0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
 #2: ffff888079c18af0 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108
2 locks held by getty/8072:
 #0: ffff88802ffdd0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003f1b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by syz-executor/12839:
 #0: ffff88806495c0e0 (&type->s_umount_key#56){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff88806495c0e0 (&type->s_umount_key#56){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff88806495c0e0 (&type->s_umount_key#56){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
 #1: ffffffff8df42d78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
 #1: ffffffff8df42d78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:957
4 locks held by syz.1.2040/13906:
2 locks held by syz.1.2040/13930:
 #0: ffff88814cc0c420 (sb_writers#16){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508
 #1: ffff888079c18ea0 (&type->i_mutex_dir_key#9/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1025 [inline]
 #1: ffff888079c18ea0 (&type->i_mutex_dir_key#9/1){+.+.}-{4:4}, at: do_unlinkat+0x1c7/0x560 fs/namei.c:4724
1 lock held by syz.1.2040/13934:
 #0: ffff888079c18ea0 (&type->i_mutex_dir_key#9){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:995 [inline]
 #0: ffff888079c18ea0 (&type->i_mutex_dir_key#9){++++}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1832
2 locks held by syz.1.2040/13942:
 #0: ffff88814cc0c420 (sb_writers#16){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508
 #1: ffff888079c18ea0 (&type->i_mutex_dir_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
 #1: ffff888079c18ea0 (&type->i_mutex_dir_key#9){++++}-{4:4}, at: open_last_lookups fs/namei.c:3892 [inline]
 #1: ffff888079c18ea0 (&type->i_mutex_dir_key#9){++++}-{4:4}, at: path_openat+0x8da/0x3830 fs/namei.c:4131
1 lock held by syz.1.2040/13943:
 #0: ffff88814cc0c0e0 (&type->s_umount_key#60){++++}-{4:4}, at: do_remount fs/namespace.c:3276 [inline]
 #0: ffff88814cc0c0e0 (&type->s_umount_key#60){++++}-{4:4}, at: path_mount+0xcd4/0xfe0 fs/namespace.c:4029
1 lock held by syz.3.2397/15293:
 #0: ffff88807ee14d20 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:377

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
 watchdog+0xf60/0xfa0 kernel/hung_task.c:495
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 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: 13906 Comm: syz.1.2040 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__sanitizer_cov_trace_pc+0x4a/0x70 kernel/kcov.c:223
Code: 81 fa 00 01 00 00 75 35 83 b9 7c 16 00 00 00 74 2c 8b 91 58 16 00 00 83 fa 02 75 21 48 8b 91 60 16 00 00 48 8b 32 48 8d 7e 01 <8b> 89 5c 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 e9 b9 3c
RSP: 0018:ffffc9000df3f2a0 EFLAGS: 00000246
RAX: ffffffff834540bf RBX: 0000000000000004 RCX: ffff888026ae0000
RDX: ffffc90011601000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: 0000000000000000 R08: ffff88804c30011f R09: 1ffff11009860023
R10: dffffc0000000000 R11: ffffed1009860024 R12: dffffc0000000000
R13: ffff88804c300000 R14: 0000000000000000 R15: 1ffff11009860002
FS:  00007fa49f03f6c0(0000) GS:ffff88812613e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000000c0 CR3: 000000006875f000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 dtSplitRoot+0x77f/0x16c0 fs/jfs/jfs_dtree.c:1979
 dtSplitUp fs/jfs/jfs_dtree.c:993 [inline]
 dtInsert+0xef8/0x5f40 fs/jfs/jfs_dtree.c:871
 jfs_create+0x6c8/0xa80 fs/jfs/namei.c:137
 lookup_open fs/namei.c:3796 [inline]
 open_last_lookups fs/namei.c:3895 [inline]
 path_openat+0x14f4/0x3830 fs/namei.c:4131
 do_filp_open+0x1fa/0x410 fs/namei.c:4161
 do_sys_openat2+0x121/0x1c0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_creat fs/open.c:1530 [inline]
 __se_sys_creat fs/open.c:1524 [inline]
 __x64_sys_creat+0x8f/0xc0 fs/open.c:1524
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa49e18efc9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa49f03f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fa49e3e5fa0 RCX: 00007fa49e18efc9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000300
RBP: 00007fa49e211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa49e3e6038 R14: 00007fa49e3e5fa0 R15: 00007ffd428945b8
 </TASK>