syzbot

INFO: task syz-executor127:5851 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc6-syzkaller-00052-g9f35e33144ae #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor127 state:D stack:29224 pid:5851  tgid:5846  ppid:5844   task_flags:0x400040 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x168f/0x4c70 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917
 rwsem_down_read_slowpath+0x552/0x880 kernel/locking/rwsem.c:1084
 __down_read_common kernel/locking/rwsem.c:1248 [inline]
 __down_read kernel/locking/rwsem.c:1261 [inline]
 down_read+0x98/0x2e0 kernel/locking/rwsem.c:1526
 inode_lock_shared include/linux/fs.h:877 [inline]
 lookup_slow+0x46/0x70 fs/namei.c:1833
 walk_component fs/namei.c:2138 [inline]
 link_path_walk+0x925/0xe50 fs/namei.c:2503
 path_parentat fs/namei.c:2707 [inline]
 __filename_parentat+0x246/0x670 fs/namei.c:2731
 filename_parentat fs/namei.c:2749 [inline]
 filename_create+0xcf/0x470 fs/namei.c:4113
 do_mkdirat+0xa0/0x590 fs/namei.c:4384
 __do_sys_mkdirat fs/namei.c:4409 [inline]
 __se_sys_mkdirat fs/namei.c:4407 [inline]
 __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4407
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f85166f3349
RSP: 002b:00007f8516686168 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f851677a6b8 RCX: 00007f85166f3349
RDX: 00000000000001ff RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007f851677a6b0 R08: 00007ffe1d4ccee7 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f851677a6bc
R13: 000000000000006e R14: 00007ffe1d4cce00 R15: 00007ffe1d4ccee8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8df3dce0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df3dce0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8df3dce0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764
1 lock held by syslogd/5171:
 #0: ffff8880b89399d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605
2 locks held by getty/5580:
 #0: ffff88803120e0a0 (&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 syz-executor127/5847:
1 lock held by syz-executor127/5851:
 #0: ffff88807b516748 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:877 [inline]
 #0: ffff88807b516748 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1833

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc6-syzkaller-00052-g9f35e33144ae #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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:274 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:437
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5847 Comm: syz-executor127 Not tainted 6.15.0-rc6-syzkaller-00052-g9f35e33144ae #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:869 [inline]
RIP: 0010:ext4_update_other_inodes_time fs/ext4/inode.c:5170 [inline]
RIP: 0010:ext4_do_update_inode fs/ext4/inode.c:5216 [inline]
RIP: 0010:ext4_mark_iloc_dirty+0x1491/0x1ca0 fs/ext4/inode.c:5869
Code: 50 ff e8 22 96 c3 fe eb d2 e8 3b 02 50 ff 48 8b 6c 24 48 eb 05 e8 2f 02 50 ff e8 7a 4f df 08 89 c3 31 ff 89 c6 e8 5f 06 50 ff <85> db 74 15 e8 b6 29 37 ff 84 c0 74 18 e8 0d 02 50 ff 48 8b 5c 24
RSP: 0018:ffffc900045aeff8 EFLAGS: 00000293
RAX: ffffffff826feee1 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff888034a7bc00 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900045af128 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff826fe143 R12: 0000000000000013
R13: 0000000000000002 R14: dffffc0000000000 R15: ffff88807704ee80
FS:  00007f85166a76c0(0000) GS:ffff8881261fb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000564fff3f9168 CR3: 000000002f466000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __ext4_mark_inode_dirty+0x4be/0x700 fs/ext4/inode.c:6074
 ext4_dirty_inode+0xd0/0x110 fs/ext4/inode.c:6103
 __mark_inode_dirty+0x2ce/0xdf0 fs/fs-writeback.c:2527
 mark_inode_dirty include/linux/fs.h:2545 [inline]
 dquot_alloc_space include/linux/quotaops.h:319 [inline]
 dquot_alloc_block include/linux/quotaops.h:336 [inline]
 ext4_xattr_block_set+0x12ca/0x2ac0 fs/ext4/xattr.c:2048
 ext4_xattr_set_handle+0xdfb/0x1590 fs/ext4/xattr.c:2447
 ext4_initxattrs+0x9f/0x110 fs/ext4/xattr_security.c:44
 security_inode_init_security+0x2a0/0x3f0 security/security.c:1852
 __ext4_new_inode+0x3257/0x3bd0 fs/ext4/ialloc.c:1326
 ext4_create+0x22d/0x460 fs/ext4/namei.c:2824
 lookup_open fs/namei.c:3701 [inline]
 open_last_lookups fs/namei.c:3800 [inline]
 path_openat+0x14f4/0x3830 fs/namei.c:4036
 do_filp_open+0x1fa/0x410 fs/namei.c:4066
 do_sys_openat2+0x121/0x1c0 fs/open.c:1429
 do_sys_open fs/open.c:1444 [inline]
 __do_sys_openat fs/open.c:1460 [inline]
 __se_sys_openat fs/open.c:1455 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1455
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f85166f3349
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 18 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f85166a7168 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f851677a6a8 RCX: 00007f85166f3349
RDX: 000000000000275a RSI: 0000200000000080 RDI: 00000000ffffff9c
RBP: 00007f851677a6a0 R08: 00007f85166a76c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f851677a6ac
R13: 0000000000000006 R14: 00007ffe1d4cce00 R15: 00007ffe1d4ccee8
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.397 msecs