syzbot

INFO: task syz-executor:5912 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:21616 pid:5912  ppid:1      flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 io_schedule+0x80/0xd0 kernel/sched/core.c:9023
 folio_wait_bit_common+0x714/0xfa0 mm/filemap.c:1329
 truncate_inode_pages_range+0xa8e/0xfb0 mm/truncate.c:446
 evict+0x4dd/0x8d0 fs/inode.c:707
 dispose_list fs/inode.c:738 [inline]
 evict_inodes+0x606/0x6a0 fs/inode.c:792
 generic_shutdown_super+0x97/0x2b0 fs/super.c:672
 kill_block_super+0x44/0x90 fs/super.c:1660
 deactivate_locked_super+0x97/0x100 fs/super.c:481
 cleanup_mnt+0x43b/0x4d0 fs/namespace.c:1259
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc540d9e017
RSP: 002b:00007ffc97da64c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fc540e32120 RCX: 00007fc540d9e017
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc97da6580
RBP: 00007ffc97da6580 R08: 00007ffc97da7580 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc97da7610
R13: 00007fc540e32120 R14: 000000000002d1fe R15: 00007ffc97da7650
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/0:1/9:
5 locks held by kworker/u4:0/11:
1 lock held by khungtaskd/29:
 #0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
2 locks held by kworker/u4:12/3482:
2 locks held by getty/5538:
 #0: ffff88802dae70a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000328b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x433/0x1390 drivers/tty/n_tty.c:2217
1 lock held by syz-executor/5912:
 #0: ffff88802f0fa0e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88802f0fa0e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88802f0fa0e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
1 lock held by syz-executor/5961:
 #0: ffff88807e4760e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88807e4760e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88807e4760e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
1 lock held by syz-executor/5976:
 #0: ffff8880781840e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff8880781840e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff8880781840e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
1 lock held by syz-executor/5992:
 #0: ffff88807b2580e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88807b2580e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88807b2580e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
1 lock held by syz-executor/6013:
 #0: ffff88801baf40e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88801baf40e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88801baf40e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
1 lock held by syz-executor/6034:
 #0: ffff88805af740e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88805af740e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88805af740e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
1 lock held by syz-executor/6055:
 #0: ffff88806e4160e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88806e4160e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88806e4160e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
1 lock held by syz-executor/6084:
 #0: ffff88805dd460e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88805dd460e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88805dd460e0 (&type->s_umount_key#56){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513

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

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf3d/0xf80 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 11 Comm: kworker/u4:0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:do_csum lib/checksum.c:83 [inline]
RIP: 0010:ip_fast_csum+0x1bf/0x2b0 lib/checksum.c:108
Code: 00 fc ff df 89 ee 83 e6 02 31 ff e8 ab d0 2a fd 89 e8 83 e0 02 75 07 e8 ef cc 2a fd eb 24 e8 e8 cc 2a fd 4c 89 f0 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 bd 00 00 00 41 0f b7 06 41 01 c7 49 83
RSP: 0018:ffffc90000107a90 EFLAGS: 00000a02
RAX: 1ffff11004d27004 RBX: 0000000000000000 RCX: ffff88801be4bc00
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000012 R08: ffff88801be4bc00 R09: 0000000000000003
R10: 000000000000002e R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000000 R14: ffff888026938020 R15: 000000000000c731
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f25660b120 CR3: 000000002e8ee000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:771 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline]
 nsim_dev_trap_report_work+0x583/0xb00 drivers/net/netdevsim/dev.c:851
 process_one_work kernel/workqueue.c:2653 [inline]
 process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>