syzbot

INFO: task syz-executor144:5829 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc6-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor144 state:D stack:28024 pid:5829  tgid:5824  ppid:5822   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_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1176
 __down_write_common kernel/locking/rwsem.c:1304 [inline]
 __down_write kernel/locking/rwsem.c:1313 [inline]
 down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1578
 inode_lock include/linux/fs.h:867 [inline]
 open_last_lookups fs/namei.c:3797 [inline]
 path_openat+0x8da/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_creat fs/open.c:1522 [inline]
 __se_sys_creat fs/open.c:1516 [inline]
 __x64_sys_creat+0x8f/0xc0 fs/open.c:1516
 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: 0033:0x7f4148283349
RSP: 002b:00007f4148216168 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007f414830a6b8 RCX: 00007f4148283349
RDX: ffffffffffffffb0 RSI: 0000000000000109 RDI: 0000200000000080
RBP: 00007f414830a6b0 R08: 00007f41482166c0 R09: 0000000000000000
R10: 00007ffd44bf0d47 R11: 0000000000000246 R12: 00007f414830a6bc
R13: 000000000000006e R14: 00007ffd44bf0c60 R15: 00007ffd44bf0d48
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8df3d860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df3d860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8df3d860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764
2 locks held by getty/5582:
 #0: ffff888030fdb0a0 (&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-executor144/5825:
2 locks held by syz-executor144/5829:
 #0: ffff888030c72420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556
 #1: ffff888075c88e20 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #1: ffff888075c88e20 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: open_last_lookups fs/namei.c:3797 [inline]
 #1: ffff888075c88e20 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: path_openat+0x8da/0x3830 fs/namei.c:4036

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc6-syzkaller #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: 5825 Comm: syz-executor144 Not tainted 6.15.0-rc6-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:151 [inline]
RIP: 0010:lock_is_held_type+0x118/0x190 kernel/locking/lockdep.c:5940
Code: 01 00 00 00 48 c7 c7 f6 19 92 8d e8 92 17 00 00 b8 ff ff ff ff 65 0f c1 05 d5 80 23 07 83 f8 01 75 44 48 c7 04 24 00 00 00 00 <9c> 8f 04 24 f7 04 24 00 02 00 00 75 4c 41 f7 c4 00 02 00 00 74 01
RSP: 0018:ffffc9000403ef98 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 7a94456ac6f02c00
RDX: 0000000000000000 RSI: ffffffff8d9219f6 RDI: ffffffff8bc0ffa0
RBP: 00000000ffffffff R08: ffff888030c70387 R09: 1ffff1100618e070
R10: dffffc0000000000 R11: ffffed100618e071 R12: 0000000000000246
R13: ffff888045d91e00 R14: ffffffff8df3d920 R15: 0000000000000003
FS:  00007f41482376c0(0000) GS:ffff8881261fb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000558855da53f0 CR3: 000000007dc58000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_is_held include/linux/lockdep.h:249 [inline]
 __might_resched+0xf5/0x610 kernel/sched/core.c:8780
 __ext4_mark_inode_dirty+0x90/0x700 fs/ext4/inode.c:6064
 ext4_dirty_inode+0xd0/0x110 fs/ext4/inode.c:6103
 __mark_inode_dirty+0x2ce/0xdf0 fs/fs-writeback.c:2527
 mark_inode_dirty_sync include/linux/fs.h:2550 [inline]
 dquot_free_space include/linux/quotaops.h:380 [inline]
 dquot_free_block include/linux/quotaops.h:390 [inline]
 ext4_xattr_block_set+0x148e/0x2ac0 fs/ext4/xattr.c:2073
 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+0x29d/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+0x14f1/0x3830 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: 0033:0x7f4148283349
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:00007f4148237168 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f414830a6a8 RCX: 00007f4148283349
RDX: 000000000000275a RSI: 0000200000000840 RDI: 00000000ffffff9c
RBP: 00007f414830a6a0 R08: 00007f41482376c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f414830a6ac
R13: 0000000000000006 R14: 00007ffd44bf0c60 R15: 00007ffd44bf0d48
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.235 msecs