syzbot

INFO: task syz-executor405:5841 blocked for more than 143 seconds.
      Not tainted 6.13.0-rc2-syzkaller-00031-gf92f4749861b #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor405 state:D stack:27504 pid:5841  tgid:5838  ppid:5837   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: 0033:0x7ff13f9f4849
RSP: 002b:00007ff13f98a218 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007ff13fa7c6d8 RCX: 00007ff13f9f4849
RDX: 00007ff13f9cdfb6 RSI: 0000000000000000 RDI: 00007ff13f98afb0
RBP: 00007ff13fa7c6d0 R08: 00007ffce2fc7077 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff13fa48086
R13: 00007ff13fa4807e R14: 633d73726f727265 R15: 0030656c69662f2e
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744
2 locks held by getty/5572:
 #0: ffff88814d4a10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900032fb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
3 locks held by syz-executor405/5840:
2 locks held by syz-executor405/5841:
 #0: ffff88807d95a0e0 (&type->s_umount_key#64){.+.+}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff88807d95a0e0 (&type->s_umount_key#64){.+.+}-{4:4}, at: super_lock+0x27c/0x400 fs/super.c:120
 #1: ffff88807d9580e8 (&sbi->s_lock){+.+.}-{4:4}, at: exfat_sync_fs+0xb0/0x160 fs/exfat/super.c:56

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-rc2-syzkaller-00031-gf92f4749861b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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:234 [inline]
 watchdog+0xff6/0x1040 kernel/hung_task.c:397
 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5840 Comm: syz-executor405 Not tainted 6.13.0-rc2-syzkaller-00031-gf92f4749861b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x10/0xb0 kernel/rcu/tree.c:737
Code: 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 53 65 ff 05 48 db 7e 7e <e8> db 5d 3b 0a 89 c3 83 f8 08 73 7a 49 bf 00 00 00 00 00 fc ff df
RSP: 0018:ffffc9000401f488 EFLAGS: 00000083
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81a7289c
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90183af0
RBP: ffffc9000401f5f8 R08: ffffffff90183af7 R09: 1ffffffff203075e
R10: dffffc0000000000 R11: fffffbfff203075f R12: 0000000000000246
R13: dffffc0000000000 R14: 0000000000000200 R15: 00000000000000a0
FS:  00007ff13f9ab6c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555571eef738 CR3: 0000000073fd8000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 trace_irq_disable+0x3b/0x120 include/trace/events/preemptirq.h:36
 lookup_bh_lru fs/buffer.c:1359 [inline]
 __find_get_block+0x190/0x1150 fs/buffer.c:1394
 bdev_getblk+0x33/0x670 fs/buffer.c:1425
 __bread_gfp+0x86/0x400 fs/buffer.c:1485
 sb_bread include/linux/buffer_head.h:346 [inline]
 exfat_get_dentry+0x53b/0x730 fs/exfat/dir.c:672
 exfat_readdir fs/exfat/dir.c:118 [inline]
 exfat_iterate+0x9f9/0x2ce0 fs/exfat/dir.c:242
 wrap_directory_iterator+0x91/0xd0 fs/readdir.c:65
 iterate_dir+0x571/0x800 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:403 [inline]
 __se_sys_getdents64+0x1e2/0x4b0 fs/readdir.c:389
 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: 0033:0x7ff13f9f4849
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:00007ff13f9ab218 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007ff13fa7c6c8 RCX: 00007ff13f9f4849
RDX: 0000000000001000 RSI: 0000000020000f80 RDI: 0000000000000004
RBP: 00007ff13fa7c6c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff13fa48086
R13: 00007ff13fa4807e R14: 633d73726f727265 R15: 0030656c69662f2e
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.207 msecs