INFO: task syz.5.240:7398 blocked for more than 143 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.240       state:D stack:25120 pid:7398  tgid:7387  ppid:6732   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0x1553/0x5240 kernel/sched/core.c:6908
 __schedule_loop kernel/sched/core.c:6990 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7286
 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline]
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
 __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760
 __rwbase_read_lock+0xc3/0x180 kernel/locking/rwbase_rt.c:114
 rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline]
 __down_read kernel/locking/rwsem.c:1466 [inline]
 down_read+0x132/0x200 kernel/locking/rwsem.c:1539
 inode_lock_shared include/linux/fs.h:1043 [inline]
 lookup_slow+0x46/0x70 fs/namei.c:1932
 walk_component fs/namei.c:2279 [inline]
 lookup_last fs/namei.c:2780 [inline]
 path_lookupat+0x3f5/0x8c0 fs/namei.c:2804
 filename_lookup+0x256/0x5d0 fs/namei.c:2833
 do_sys_truncate+0xbb/0x1c0 fs/open.c:140
 __do_sys_truncate fs/open.c:154 [inline]
 __se_sys_truncate fs/open.c:152 [inline]
 __x64_sys_truncate+0x5b/0x70 fs/open.c:152
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f090c8ec799
RSP: 002b:00007f090ab1d028 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f090cb66090 RCX: 00007f090c8ec799
RDX: 0000000000000000 RSI: 0000000000000fff RDI: 0000200000000080
RBP: 00007f090c982bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f090cb66128 R14: 00007f090cb66090 R15: 00007ffc833ef398
 </TASK>
INFO: task syz.5.240:7399 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.240       state:D stack:28592 pid:7399  tgid:7387  ppid:6732   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0x1553/0x5240 kernel/sched/core.c:6908
 __schedule_loop kernel/sched/core.c:6990 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7286
 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline]
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
 __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760
 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800
 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
 rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244
 inode_lock include/linux/fs.h:1028 [inline]
 open_last_lookups fs/namei.c:4580 [inline]
 path_openat+0xb5e/0x38a0 fs/namei.c:4827
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f090c8ec799
RSP: 002b:00007f090aafc028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f090cb66180 RCX: 00007f090c8ec799
RDX: 000000000000275a RSI: 0000200000000200 RDI: ffffffffffffff9c
RBP: 00007f090c982bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f090cb66218 R14: 00007f090cb66180 R15: 00007ffc833ef398
 </TASK>
INFO: task syz.5.240:7402 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.240       state:D stack:29024 pid:7402  tgid:7387  ppid:6732   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0x1553/0x5240 kernel/sched/core.c:6908
 __schedule_loop kernel/sched/core.c:6990 [inline]
 rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7286
 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline]
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
 __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760
 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800
 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
 rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244
 inode_lock_nested include/linux/fs.h:1073 [inline]
 __start_dirop fs/namei.c:2923 [inline]
 start_dirop fs/namei.c:2934 [inline]
 filename_create+0x200/0x370 fs/namei.c:4922
 filename_mkdirat+0xd2/0x520 fs/namei.c:5259
 __do_sys_mkdirat fs/namei.c:5287 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5284
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f090c8eb607
RSP: 002b:00007f090a6d8e58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f090a6d8ee0 RCX: 00007f090c8eb607
RDX: 00000000000001ff RSI: 0000200000000040 RDI: 00000000ffffff9c
RBP: 0000200000000140 R08: 00002000000000c0 R09: 0000000000000000
R10: 0000200000000140 R11: 0000000000000246 R12: 0000200000000040
R13: 00007f090a6d8ea0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Showing all locks held in the system:
4 locks held by pr/legacy/17:
1 lock held by khungtaskd/38:
 #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
6 locks held by kworker/u8:15/5107:
2 locks held by getty/5561:
 #0: ffff88803726f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
2 locks held by udevd/5911:
3 locks held by syz.5.240/7388:
1 lock held by syz.5.240/7398:
 #0: ffff888061d5e3b0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff888061d5e3b0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1932
2 locks held by syz.5.240/7399:
 #0: ffff888025226480 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
 #1: ffff888061d5e3b0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #1: ffff888061d5e3b0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: open_last_lookups fs/namei.c:4580 [inline]
 #1: ffff888061d5e3b0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: path_openat+0xb5e/0x38a0 fs/namei.c:4827
2 locks held by syz.5.240/7402:
 #0: ffff888025226480 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
 #1: ffff888061d5e3b0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline]
 #1: ffff888061d5e3b0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline]
 #1: ffff888061d5e3b0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline]
 #1: ffff888061d5e3b0 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:4922
2 locks held by kworker/u8:8/8836:
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
 #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
 #1: ffffc9000400fc40 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #1: ffffc9000400fc40 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
3 locks held by syz.9.476/9212:
3 locks held by syz.2.477/9221:
2 locks held by syz.4.478/9224:
2 locks held by syz.5.479/9227:
3 locks held by syz.0.481/9233:
1 lock held by rm/9234:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xfd9/0x1030 kernel/hung_task.c:515
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 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: 9224 Comm: syz.4.478 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:3802 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3821 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3876 [inline]
RIP: 0010:__lock_acquire+0xc4c/0x2cf0 kernel/locking/lockdep.c:5237
Code: 48 ff cb f7 c1 00 60 00 00 74 c3 e9 90 00 00 00 48 c7 c7 90 ac c9 8d 4c 89 fe e8 0f db 39 03 48 8b 54 24 18 eb c3 48 8b 48 18 <48> 39 e9 0f 84 b9 00 00 00 48 8b 40 08 48 85 c0 0f 84 ca fe ff ff
RSP: 0018:ffffc90005b97520 EFLAGS: 00000093
RAX: ffffffff9362d610 RBX: 0000000000048548 RCX: 90083d3ce5931bb6
RDX: 000000001423ea00 RSI: 00000000911cb7d4 RDI: ffff88802e823d00
RBP: 90083d3ce5931bb6 R08: ffffffff82394718 R09: ffff888064d71bd8
R10: dffffc0000000000 R11: fffffbfff1ed4832 R12: ffff88802e824908
R13: ffff88802e824908 R14: ffff88802e823d00 R15: 0000000000000002
FS:  00007fc29cdbe6c0(0000) GS:ffff88812633f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8dd0ad0eb8 CR3: 0000000050ac0000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
 rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56
 spin_lock include/linux/spinlock_rt.h:45 [inline]
 inode_add_bytes+0x38/0x140 fs/stat.c:919
 __dquot_alloc_space+0x285/0xea0 fs/quota/dquot.c:1698
 dquot_alloc_space_nodirty include/linux/quotaops.h:299 [inline]
 dquot_alloc_block_nodirty include/linux/quotaops.h:326 [inline]
 shmem_inode_acct_blocks+0x2a1/0x460 mm/shmem.c:242
 shmem_alloc_and_add_folio mm/shmem.c:2002 [inline]
 shmem_get_folio_gfp+0x90d/0x1a80 mm/shmem.c:2567
 shmem_get_folio mm/shmem.c:2673 [inline]
 shmem_write_begin+0x166/0x320 mm/shmem.c:3327
 generic_perform_write+0x2af/0x8b0 mm/filemap.c:4314
 shmem_file_write_iter+0xfb/0x120 mm/shmem.c:3502
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x629/0xba0 fs/read_write.c:688
 ksys_write+0x156/0x270 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc29eb2cfce
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007fc29cdbdda8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc29cdbe6c0 RCX: 00007fc29eb2cfce
RDX: 00000000013bd7ef RSI: 00007fc29499e000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007fc29cdbdee0 R14: 00007fc29cdbdea0 R15: 00007fc29499e000
 </TASK>