syzbot

INFO: task syz.2.3069:18284 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc1-syzkaller-00005-g488ef3560196 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.3069      state:D stack:28216 pid:18284 tgid:18284 ppid:5817   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x116a/0x5de0 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6878
 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common+0x2fc/0x4e0 kernel/sched/completion.c:116
 __vhost_worker_flush+0x1cd/0x210 drivers/vhost/vhost.c:288
 vhost_worker_flush drivers/vhost/vhost.c:295 [inline]
 vhost_dev_flush+0xac/0x110 drivers/vhost/vhost.c:305
 vhost_net_flush+0x1d/0x1b0 drivers/vhost/net.c:1374
 vhost_net_release+0xa2/0x260 drivers/vhost/net.c:1395
 __fput+0x3ff/0xb70 fs/file_table.c:465
 task_work_run+0x14d/0x240 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:114
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff7e638e929
RSP: 002b:00007ffe7205b2c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ff7e65b7ba0 RCX: 00007ff7e638e929
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007ff7e65b7ba0 R08: 000000000000bd94 R09: 000000067205b5bf
R10: 00007ff7e65b7ac0 R11: 0000000000000246 R12: 0000000000129e04
R13: 00007ffe7205b3c0 R14: ffffffffffffffff R15: 00007ffe7205b3e0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e5c4840 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e5c4840 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e5c4840 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6770
2 locks held by getty/5578:
 #0: ffff8880323cb0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000361c2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
3 locks held by syz.5.3786/20506:
 #0: ffffffff9034cbe8 (rtnl_mutex){+.+.}-{4:4}, at: bpf_xdp_link_release+0x1d/0x7c0 net/core/dev.c:10229
 #1: ffffffff90351e08 (bpf_dispatcher_xdp.mutex){+.+.}-{4:4}, at: bpf_dispatcher_change_prog+0x38/0xa80 kernel/bpf/dispatcher.c:146
 #2: ffffffff8e5cfe38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:304

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc1-syzkaller-00005-g488ef3560196 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
 watchdog+0xf70/0x12c0 kernel/hung_task.c:470
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 20364 Comm: udevd Not tainted 6.16.0-rc1-syzkaller-00005-g488ef3560196 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:218 [inline]
RIP: 0010:unwind_next_frame+0x23d/0x20a0 arch/x86/kernel/unwind_orc.c:494
Code: 89 74 24 20 89 44 24 18 e8 70 10 b8 00 48 8b 4c 24 30 48 8b 44 24 28 8b 74 24 20 44 8b 5c 24 18 8d 50 01 8b 0c 8d f4 de f8 91 <48> b8 00 00 00 00 00 fc ff df 48 8d 3c 95 f4 de f8 91 49 89 f8 49
RSP: 0018:ffffc9000c67f368 EFLAGS: 00000246
RAX: 0000000000013997 RBX: 0000000000000001 RCX: 000000000003c7ca
RDX: 0000000000013998 RSI: 00000000000a838c RDI: ffffffff91fdc550
RBP: ffffc9000c67f420 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000013997 R12: ffffc9000c67f428
R13: ffffc9000c67f3d8 R14: ffffc9000c67f40d R15: ffffffff8239977a
FS:  00007f7d87957880(0000) GS:ffff888124754000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f70eff8 CR3: 0000000073f29000 CR4: 00000000003526f0
DR0: 0000000000000040 DR1: 0000000000000004 DR2: 0000000000000003
DR3: 00000000000010e3 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x2b4/0x4d0 mm/slub.c:4842
 tomoyo_check_open_permission+0x19f/0x3c0 security/tomoyo/file.c:786
 tomoyo_file_open+0x6b/0x90 security/tomoyo/tomoyo.c:334
 security_file_open+0x84/0x1e0 security/security.c:3114
 do_dentry_open+0x596/0x1c10 fs/open.c:941
 vfs_open+0x82/0x3f0 fs/open.c:1094
 do_open fs/namei.c:3887 [inline]
 path_openat+0x1de4/0x2cb0 fs/namei.c:4046
 do_filp_open+0x20b/0x470 fs/namei.c:4073
 do_sys_openat2+0x11b/0x1d0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x174/0x210 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7d872a7407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fff53d107a0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f7d87957880 RCX: 00007f7d872a7407
RDX: 00000000000a0800 RSI: 0000560734bea9d0 RDI: ffffffffffffff9c
RBP: 00005607349b52c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000560734c03cb0
R13: 0000560734bfa8f0 R14: 0000000000000000 R15: 0000560734c03cb0
 </TASK>