INFO: task syz.4.6058:19359 blocked for more than 143 seconds. Not tainted 6.12.0-rc3-syzkaller-00183-g6efbea77b390 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.6058 state:D stack:26736 pid:19359 tgid:19358 ppid:5243 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5322 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6682 __schedule_loop kernel/sched/core.c:6759 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6774 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6831 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752 exfat_sync_fs+0xb0/0x160 fs/exfat/super.c:56 iterate_supers+0xc8/0x190 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: 0033:0x7f231097dff9 RSP: 002b:00007f23116b3038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f2310b35f80 RCX: 00007f231097dff9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f23109f0296 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f2310b35f80 R15: 00007ffffae58e98 Showing all locks held in the system: 1 lock held by khungtaskd/30: #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6720 2 locks held by kworker/u8:3/53: 2 locks held by getty/4985: #0: ffff88802e6560a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211 3 locks held by syz-executor/5240: 2 locks held by syz.4.6058/19359: #0: ffff88807cff80e0 (&type->s_umount_key#101){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline] #0: ffff88807cff80e0 (&type->s_umount_key#101){++++}-{3:3}, at: super_lock+0x27c/0x400 fs/super.c:120 #1: ffff8880272580e8 (&sbi->s_lock#2){+.+.}-{3:3}, at: exfat_sync_fs+0xb0/0x160 fs/exfat/super.c:56 1 lock held by sed/24253: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-rc3-syzkaller-00183-g6efbea77b390 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __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+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 4669 Comm: klogd Not tainted 6.12.0-rc3-syzkaller-00183-g6efbea77b390 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:lock_acquire+0x104/0x550 kernel/locking/lockdep.c:5798 Code: ac 0e 73 16 e8 2d 7f 0a 00 84 c0 75 0d 80 3d fc 63 96 0e 00 0f 84 f9 02 00 00 48 c7 c0 bc 31 1d 90 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 ff 02 00 00 83 3d a9 da ac 0e 00 0f 84 42 01 00 00 65 RSP: 0018:ffffc90009287160 EFLAGS: 00000013 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff817056d4 RDX: 0000000000000000 RSI: ffffffff8c610100 RDI: ffffffff8c6100c0 RBP: ffffc900092872a8 R08: ffffffff901cff6f R09: 1ffffffff2039fed R10: dffffc0000000000 R11: fffffbfff2039fee R12: 1ffff92001250e34 R13: dffffc0000000000 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007f9c0a5ed380(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055d1f0723950 CR3: 000000002d068000 CR4: 0000000000350ef0 Call Trace: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 __debug_check_no_obj_freed lib/debugobjects.c:978 [inline] debug_check_no_obj_freed+0x234/0x580 lib/debugobjects.c:1019 free_pages_prepare mm/page_alloc.c:1115 [inline] free_unref_page+0x41b/0xf20 mm/page_alloc.c:2638 discard_slab mm/slub.c:2677 [inline] __put_partials+0xeb/0x130 mm/slub.c:3145 put_cpu_partial+0x17c/0x250 mm/slub.c:3220 __slab_free+0x2ea/0x3d0 mm/slub.c:4449 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:247 [inline] slab_post_alloc_hook mm/slub.c:4085 [inline] slab_alloc_node mm/slub.c:4134 [inline] kmem_cache_alloc_node_noprof+0x16b/0x320 mm/slub.c:4186 __alloc_skb+0x1c3/0x440 net/core/skbuff.c:668 alloc_skb include/linux/skbuff.h:1322 [inline] alloc_skb_with_frags+0xc3/0x820 net/core/skbuff.c:6612 sock_alloc_send_pskb+0x91a/0xa60 net/core/sock.c:2883 unix_dgram_sendmsg+0x6d3/0x1f80 net/unix/af_unix.c:2027 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg+0x223/0x270 net/socket.c:744 __sys_sendto+0x39b/0x4f0 net/socket.c:2214 __do_sys_sendto net/socket.c:2226 [inline] __se_sys_sendto net/socket.c:2222 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2222 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: 0033:0x7f9c0a74f9b5 Code: 8b 44 24 08 48 83 c4 28 48 98 c3 48 98 c3 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 26 45 31 c9 45 31 c0 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 7a 48 8b 15 44 c4 0c 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffd254df6e8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f9c0a74f9b5 RDX: 0000000000000049 RSI: 0000562910ee19f0 RDI: 0000000000000003 RBP: 0000562910ed8910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000246 R12: 0000000000000013 R13: 00007f9c0a8dd212 R14: 00007ffd254df7e8 R15: 0000000000000000