syzbot

INFO: task syz.1.1055:7233 blocked for more than 143 seconds.
      Not tainted 5.15.167-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1055      state:D stack:24984 pid: 7233 ppid:  6550 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6515
 __mutex_lock_common+0xe34/0x25a0 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 exfat_sync_fs+0x67/0x100 fs/exfat/super.c:64
 iterate_supers+0x127/0x1e0 fs/super.c:716
 ksys_sync+0xd7/0x1c0 fs/sync.c:104
 __do_sys_sync+0xa/0x10 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fdfc721dff9
RSP: 002b:00007fdfc5696038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fdfc73d5f80 RCX: 00007fdfc721dff9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fdfc7290296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fdfc73d5f80 R15: 00007ffe9aa660a8
 </TASK>

Showing all locks held in the system:
4 locks held by ksoftirqd/0/14:
 #0: ffff8880b903a318 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
 #1: ffff8880b9027848 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x53d/0x810 kernel/sched/psi.c:891
 #2: ffffffff96a633c8 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_activate+0x63/0x4e0 lib/debugobjects.c:693
 #3: ffff88801f3398d8 (&____s->seqcount#6){----}-{0:0}, at: drm_handle_vblank_events+0x115/0x6e0 drivers/gpu/drm/drm_vblank.c:1901
1 lock held by khungtaskd/27:
 #0: ffffffff8c91fc60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3321:
 #0: ffff88814adf7098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc9000228e2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
3 locks held by syz-executor/3569:
3 locks held by kworker/u4:10/4742:
 #0: ffff888017079138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90004c27d20 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffffffff8da31d88 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
6 locks held by kworker/u4:11/4746:
1 lock held by syz.2.594/5291:
3 locks held by kworker/1:8/5485:
 #0: ffff888017070938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc9000319fd20 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffffffff8da31d88 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74
2 locks held by kworker/0:16/5909:
 #0: ffff888017072138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90003107d20 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
3 locks held by syz-executor/6532:
2 locks held by syz.3.948/6707:
2 locks held by syz.1.1055/7233:
 #0: ffff8880758be0e0 (&type->s_umount_key#73){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:714
 #1: ffff888075bb00e0 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_sync_fs+0x67/0x100 fs/exfat/super.c:64
1 lock held by syz.2.1082/7473:
3 locks held by syz.2.1347/8709:
2 locks held by syz-executor/8790:
 #0: ffffffff8da31d88 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8da31d88 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x94c/0xee0 net/core/rtnetlink.c:5615
 #1: ffffffff8c924228 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #1: ffffffff8c924228 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x280/0x740 kernel/rcu/tree_exp.h:845

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8790 Comm: syz-executor Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x32/0x60 kernel/kcov.c:206
Code: 44 15 82 7e 65 8b 15 45 15 82 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 34 16 00 00 00 74 2c 8b 91 10 16 00 00 <83> fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48 8d 7e 01 8b 89 14
RSP: 0018:ffffc90003776020 EFLAGS: 00000246
RAX: ffffffff842f0c6e RBX: ffffc900037760e0 RCX: ffff88801ff7bb80
RDX: 0000000000000000 RSI: 00000000000001ae RDI: ffffc900037760e0
RBP: 00000000000001ae R08: ffffffff842e5311 R09: ffffc900037760e0
R10: 0000000000000000 R11: dffffc0000000001 R12: 00000000ffff0a00
R13: dffffc0000000000 R14: ffffc900037760e0 R15: ffffc900037764e1
FS:  000055556a775500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1886b0d178 CR3: 00000000561f8000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 put_dec_trunc8+0x1e/0x330 lib/vsprintf.c:220
 number+0x333/0xf80 lib/vsprintf.c:507
 vsnprintf+0x1361/0x1c70 lib/vsprintf.c:2877
 sprintf+0xd6/0x120 lib/vsprintf.c:3013
 print_time kernel/printk/printk.c:1274 [inline]
 info_print_prefix+0x167/0x300 kernel/printk/printk.c:1300
 record_print_text kernel/printk/printk.c:1349 [inline]
 console_unlock+0x7c1/0x12b0 kernel/printk/printk.c:2725
 vprintk_emit+0xbf/0x150 kernel/printk/printk.c:2274
 _printk+0xd1/0x120 kernel/printk/printk.c:2299
 br_set_state+0x35b/0x610 net/bridge/br_stp.c:51
 br_init_port+0x9c/0x200 net/bridge/br_stp_if.c:39
 new_nbp+0x49d/0x640 net/bridge/br_if.c:433
 br_add_if+0x3a2/0x1200 net/bridge/br_if.c:610
 do_set_master net/core/rtnetlink.c:2543 [inline]
 do_setlink+0xdd3/0x3d80 net/core/rtnetlink.c:2754
 __rtnl_newlink net/core/rtnetlink.c:3418 [inline]
 rtnl_newlink+0x17d6/0x2070 net/core/rtnetlink.c:3540
 rtnetlink_rcv_msg+0x993/0xee0 net/core/rtnetlink.c:5618
 netlink_rcv_skb+0x1cf/0x410 net/netlink/af_netlink.c:2503
 netlink_unicast_kernel net/netlink/af_netlink.c:1326 [inline]
 netlink_unicast+0x7b6/0x980 net/netlink/af_netlink.c:1352
 netlink_sendmsg+0xa30/0xd60 net/netlink/af_netlink.c:1920
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 __sys_sendto+0x564/0x720 net/socket.c:2058
 __do_sys_sendto net/socket.c:2070 [inline]
 __se_sys_sendto net/socket.c:2066 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2066
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1750249e8c
Code: 2a 5a 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5a 02 00 48 8b
RSP: 002b:00007ffd767e3c90 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f1750f2e620 RCX: 00007f1750249e8c
RDX: 0000000000000028 RSI: 00007f1750f2e670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffd767e3ce4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f1750f2e670 R15: 0000000000000000
 </TASK>