syzbot

INFO: task syz.2.66:6477 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc5-syzkaller-00053-g8c2e52ebbe88 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.66        state:D stack:26664 pid:6477  tgid:6426  ppid:5838   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5401 [inline]
 __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6790
 __schedule_loop kernel/sched/core.c:6868 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6883
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6940
 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_nested+0x1b5/0x200 kernel/locking/rwsem.c:1694
 inode_lock_nested include/linux/fs.h:914 [inline]
 do_unlinkat+0x1bf/0x560 fs/namei.c:4646
 __do_sys_unlinkat fs/namei.c:4700 [inline]
 __se_sys_unlinkat fs/namei.c:4693 [inline]
 __x64_sys_unlinkat+0xd3/0xf0 fs/namei.c:4693
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdcc0f8e929
RSP: 002b:00007fdcc1e50038 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007fdcc11b6080 RCX: 00007fdcc0f8e929
RDX: 0000000000000000 RSI: 00002000000003c0 RDI: ffffffffffffff9c
RBP: 00007fdcc1010b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fdcc11b6080 R15: 00007ffc43ed0dd8
 </TASK>
INFO: task syz.2.66:6485 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc5-syzkaller-00053-g8c2e52ebbe88 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.66        state:D stack:28744 pid:6485  tgid:6426  ppid:5838   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5401 [inline]
 __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6790
 __schedule_loop kernel/sched/core.c:6868 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6883
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6940
 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:884 [inline]
 lookup_slow+0x46/0x70 fs/namei.c:1833
 walk_component fs/namei.c:2138 [inline]
 link_path_walk+0x935/0xea0 fs/namei.c:2506
 path_parentat fs/namei.c:2710 [inline]
 __filename_parentat+0x246/0x670 fs/namei.c:2734
 filename_parentat fs/namei.c:2752 [inline]
 do_renameat2+0x255/0xc50 fs/namei.c:5209
 __do_sys_rename fs/namei.c:5333 [inline]
 __se_sys_rename fs/namei.c:5331 [inline]
 __x64_sys_rename+0x82/0x90 fs/namei.c:5331
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdcc0f8e929
RSP: 002b:00007fdcc1e2f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 00007fdcc11b6160 RCX: 00007fdcc0f8e929
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000200000000780
RBP: 00007fdcc1010b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fdcc11b6160 R15: 00007ffc43ed0dd8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e13f160 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13f160 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e13f160 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
2 locks held by kworker/u8:2/36:
3 locks held by kworker/u8:3/37:
2 locks held by kworker/u8:4/62:
2 locks held by kworker/1:2/935:
2 locks held by getty/5595:
 #0: ffff8880309270a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900036be2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by udevd/5966:
1 lock held by udevd/6057:
 #0: ffff888148d06f20 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:884 [inline]
 #0: ffff888148d06f20 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:832
3 locks held by udevd/6196:
5 locks held by syz.2.66/6428:
 #0: ffff88823bffe428 (sb_writers#16){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff888053c59810 (&sb->s_type->i_mutex_key#24){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff888053c59810 (&sb->s_type->i_mutex_key#24){++++}-{4:4}, at: open_last_lookups fs/namei.c:3813 [inline]
 #1: ffff888053c59810 (&sb->s_type->i_mutex_key#24){++++}-{4:4}, at: path_openat+0x8da/0x3830 fs/namei.c:4052
 #2: ffff888053c59bf8 (&inode->ei_update_lock){+.+.}-{4:4}, at: __bch2_create+0x2f2/0xb90 fs/bcachefs/fs.c:567
 #3: ffff888068d04398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:161 [inline]
 #3: ffff888068d04398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:253 [inline]
 #3: ffff888068d04398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: bch2_trans_srcu_lock+0xaf/0x220 fs/bcachefs/btree_iter.c:3299
 #4: ffff888068d26710 (&c->gc_lock){++++}-{4:4}, at: bch2_btree_update_start+0x542/0x1de0 fs/bcachefs/btree_update_interior.c:1211
2 locks held by syz.2.66/6477:
 #0: ffff88823bffe428 (sb_writers#16){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff888053c59810 (&sb->s_type->i_mutex_key#24/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:914 [inline]
 #1: ffff888053c59810 (&sb->s_type->i_mutex_key#24/1){+.+.}-{4:4}, at: do_unlinkat+0x1bf/0x560 fs/namei.c:4646
1 lock held by syz.2.66/6485:
 #0: ffff888053c59810 (&sb->s_type->i_mutex_key#24){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:884 [inline]
 #0: ffff888053c59810 (&sb->s_type->i_mutex_key#24){++++}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1833
2 locks held by syz-executor/8228:
2 locks held by syz.4.331/8967:
2 locks held by rm/8990:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc5-syzkaller-00053-g8c2e52ebbe88 #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:307 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:470
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 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: 6196 Comm: udevd Not tainted 6.16.0-rc5-syzkaller-00053-g8c2e52ebbe88 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:mark_lock+0xf/0x190 kernel/locking/lockdep.c:4725
Code: 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 41 55 41 54 53 8b 46 20 89 c1 <81> e1 00 00 03 00 83 f9 01 bb 09 00 00 00 83 db 00 83 fa 08 0f 45
RSP: 0018:ffffc9000b337a98 EFLAGS: 00000002
RAX: 000000000005055d RBX: ffff888027171e00 RCX: 000000000005055d
RDX: 0000000000000008 RSI: ffff8880271728f0 RDI: ffff888027171e00
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff84977218
R10: ffffc9000b337d70 R11: ffffffff84976f20 R12: ffffffffffffff05
R13: 0000000000000004 R14: ffff8880271728f0 R15: 0000000000000000
FS:  00007f5d26762880(0000) GS:ffff888125d4f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5d2675d000 CR3: 00000000337fa000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 mark_usage kernel/locking/lockdep.c:4677 [inline]
 __lock_acquire+0x6a8/0xd20 kernel/locking/lockdep.c:5194
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
 down_read+0x46/0x2e0 kernel/locking/rwsem.c:1524
 inode_lock_shared include/linux/fs.h:884 [inline]
 blkdev_read_iter+0x2f8/0x440 block/fops.c:832
 new_sync_read fs/read_write.c:491 [inline]
 vfs_read+0x4cd/0x980 fs/read_write.c:572
 ksys_read+0x145/0x250 fs/read_write.c:715
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5d260a7407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffc86d42020 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f5d26762880 RCX: 00007f5d260a7407
RDX: 0000000000000200 RSI: 00007f5d2675c000 RDI: 0000000000000009
RBP: 0000557010e9e9c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000008000 R14: 0000557010e8d218 R15: 00007f5d2682739c
 </TASK>