syzbot

INFO: task syz.5.1086:14259 blocked for more than 142 seconds.
      Not tainted 6.12.0-syzkaller-01782-gbf9aa14fc523 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.1086      state:D stack:26136 pid:14259 tgid:14255 ppid:13768  flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x17fb/0x4be0 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6848
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905
 __mutex_lock_common kernel/locking/mutex.c:665 [inline]
 __mutex_lock+0x7e7/0xee0 kernel/locking/mutex.c:735
 exfat_sync_fs+0xb0/0x160 fs/exfat/super.c:56
 iterate_supers+0xc6/0x190 fs/super.c:934
 ksys_sync+0xdb/0x1c0 fs/sync.c:104
 __do_sys_sync+0xe/0x20 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbd60d7e819
RSP: 002b:00007fbd61b7a038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fbd60f36160 RCX: 00007fbd60d7e819
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fbd60f36160 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fbd60f36160 R15: 00007ffdd0dcc888
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
 #0: ffffffff8e941d78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline]
 #0: ffffffff8e941d78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976
1 lock held by khungtaskd/30:
 #0: ffffffff8e93c7e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e93c7e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e93c7e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744
1 lock held by udevd/5206:
 #0: ffff88803297b080 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:828 [inline]
 #0: ffff88803297b080 (&type->i_mutex_dir_key#5){++++}-{4:4}, at: lookup_slow+0x45/0x70 fs/namei.c:1807
2 locks held by getty/5593:
 #0: ffff888034b120a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
4 locks held by kworker/u8:9/6399:
3 locks held by syz.7.475/9587:
2 locks held by syz.5.1086/14259:
 #0: ffff88807bfd60e0 (&type->s_umount_key#72){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff88807bfd60e0 (&type->s_umount_key#72){++++}-{4:4}, at: super_lock+0x27c/0x400 fs/super.c:120
 #1: ffff8880342440e8 (&sbi->s_lock){+.+.}-{4:4}, at: exfat_sync_fs+0xb0/0x160 fs/exfat/super.c:56
2 locks held by syz.8.1321/16334:
 #0: ffffffff8f0569a8 (bio_slab_lock){+.+.}-{4:4}, at: bio_put_slab block/bio.c:140 [inline]
 #0: ffffffff8f0569a8 (bio_slab_lock){+.+.}-{4:4}, at: bioset_exit+0x42f/0x650 block/bio.c:1755
 #1: ffffffff8e941c40 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:4565
1 lock held by sed/16454:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-syzkaller-01782-gbf9aa14fc523 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xff4/0x1040 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 16456 Comm: dhcpcd-run-hook Not tainted 6.12.0-syzkaller-01782-gbf9aa14fc523 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline]
RIP: 0010:preempt_latency_start kernel/sched/core.c:5828 [inline]
RIP: 0010:preempt_count_add+0x7d/0x190 kernel/sched/core.c:5854
Code: 38 84 c0 0f 85 e4 00 00 00 83 3d ad 4d d8 18 00 75 11 65 8b 05 6c 8b a0 7e 0f b6 c0 3d f5 00 00 00 73 5e 65 8b 05 5b 8b a0 7e <25> ff ff ff 7f 39 d8 75 44 4c 8b 74 24 18 4c 89 f7 e8 7d 7c 0e 00
RSP: 0018:ffffc9000378ed10 EFLAGS: 00000297
RAX: 0000000080000001 RBX: 0000000000000001 RCX: ffffffff9a3b9903
RDX: dffffc0000000000 RSI: ffffffff81ed64a2 RDI: 0000000000000001
RBP: ffffc9000378ee38 R08: 0000000000000002 R09: ffffc9000378eef0
R10: ffffc9000378ee50 R11: ffffffff81809d60 R12: dffffc0000000000
R13: ffffc9000378ee00 R14: ffffffff81ed64a2 R15: dffffc0000000000
FS:  00007f323910d380(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f31cad5b000 CR3: 000000004ab74000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 unwind_next_frame+0xb0/0x22d0 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
 save_stack+0xfb/0x1f0 mm/page_owner.c:156
 __set_page_owner+0x92/0x800 mm/page_owner.c:320
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1556
 prep_new_page mm/page_alloc.c:1564 [inline]
 get_page_from_freelist+0x363e/0x3790 mm/page_alloc.c:3474
 __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4751
 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
 alloc_slab_page+0x6a/0x140 mm/slub.c:2412
 allocate_slab+0x5a/0x2f0 mm/slub.c:2578
 new_slab mm/slub.c:2631 [inline]
 ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3818
 __slab_alloc+0x58/0xa0 mm/slub.c:3908
 __slab_alloc_node mm/slub.c:3961 [inline]
 slab_alloc_node mm/slub.c:4122 [inline]
 kmem_cache_alloc_noprof+0x1c1/0x2a0 mm/slub.c:4141
 anon_vma_chain_alloc mm/rmap.c:143 [inline]
 anon_vma_clone+0x98/0x4e0 mm/rmap.c:289
 anon_vma_fork+0x87/0x580 mm/rmap.c:352
 dup_mmap kernel/fork.c:709 [inline]
 dup_mm kernel/fork.c:1675 [inline]
 copy_mm+0xc51/0x1e80 kernel/fork.c:1724
 copy_process+0x1845/0x3d50 kernel/fork.c:2375
 kernel_clone+0x223/0x880 kernel/fork.c:2787
 __do_sys_clone kernel/fork.c:2930 [inline]
 __se_sys_clone kernel/fork.c:2914 [inline]
 __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2914
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3239247a12
Code: 41 5d 41 5e 41 5f c3 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 10 48 8b 15 e7 43 0f 00 f7 d8 64 89 02 48 83
RSP: 002b:00007fff9c1f7fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 000055cb51ee1901 RCX: 00007f3239247a12
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 000055cb51ee2b70 R08: 0000000000000000 R09: 0000000000000000
R10: 00007f323910d650 R11: 0000000000000246 R12: 000055cb51ee3f70
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>