INFO: task syz-executor.0:18202 blocked for more than 143 seconds. Not tainted 6.9.0-rc5-syzkaller-00042-ge88c4cfcb7b8 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:23968 pid:18202 tgid:18202 ppid:1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5409 [inline] __schedule+0xf15/0x5d00 kernel/sched/core.c:6746 __schedule_loop kernel/sched/core.c:6823 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6838 wb_wait_for_completion+0x1b2/0x270 fs/fs-writeback.c:217 sync_inodes_sb+0x1b7/0xa40 fs/fs-writeback.c:2783 sync_filesystem+0x176/0x290 fs/sync.c:64 generic_shutdown_super+0x7e/0x3d0 fs/super.c:620 kill_block_super+0x3b/0x90 fs/super.c:1675 deactivate_locked_super+0xbe/0x1a0 fs/super.c:472 deactivate_super+0xde/0x100 fs/super.c:505 cleanup_mnt+0x222/0x450 fs/namespace.c:1267 task_work_run+0x14e/0x250 kernel/task_work.c:180 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x278/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xdc/0x260 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f54cf87f1d7 RSP: 002b:00007ffeae8c1088 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f54cf87f1d7 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffeae8c1140 RBP: 00007ffeae8c1140 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffeae8c2200 R13: 00007f54cf8c93b9 R14: 000000000010c5c6 R15: 0000000000000006 Showing all locks held in the system: 1 lock held by khungtaskd/29: #0: ffffffff8d7b0e20 (rcu_read_lock ){....}-{1:2} , at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] , at: rcu_read_lock include/linux/rcupdate.h:781 [inline] , at: debug_show_all_locks+0x75/0x340 kernel/locking/lockdep.c:6614 2 locks held by kworker/u8:8/2795: #0: ffff888019294148 ( (wq_completion)writeback ){+.+.}-{0:0} , at: process_one_work+0x1296/0x1ac0 kernel/workqueue.c:3229 #1: ffffc9000ac17d80 ( (work_completion)(&(&wb->dwork)->work) ){+.+.}-{0:0} , at: process_one_work+0x906/0x1ac0 kernel/workqueue.c:3230 2 locks held by getty/4837: #0: ffff88802ae910a0 (&tty->ldisc_sem ){++++}-{0:0} , at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc90002f062f0 ( &ldata->atomic_read_lock ){+.+.}-{3:3} , at: n_tty_read+0xfc8/0x1490 drivers/tty/n_tty.c:2201 2 locks held by syz-executor.0/18202: #0: ffff88807997a0e0 ( &type->s_umount_key #81 ){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline] ){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline] ){+.+.}-{3:3}, at: deactivate_super+0xd6/0x100 fs/super.c:504 #1: ffff888020ce87d0 (&bdi->wb_switch_rwsem ){+.+.}-{3:3} , at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:389 [inline] , at: sync_inodes_sb+0x19d/0xa40 fs/fs-writeback.c:2781 3 locks held by segctord/20894: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 29 Comm: khungtaskd Not tainted 6.9.0-rc5-syzkaller-00042-ge88c4cfcb7b8 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 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:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline] watchdog+0xf86/0x1240 kernel/hung_task.c:380 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 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 PID: 7610 Comm: kworker/u8:12 Not tainted 6.9.0-rc5-syzkaller-00042-ge88c4cfcb7b8 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:173 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0xc/0x60 kernel/kcov.c:207 Code: c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 48 8b 15 24 15 76 7e <65> 8b 05 25 15 76 7e a9 00 01 ff 00 48 8b 34 24 74 0f f6 c4 01 74 RSP: 0018:ffffc90003d1f6b0 EFLAGS: 00000297 RAX: ffffc90003d1fb78 RBX: ffffc90003d1f780 RCX: ffffffff813d14e6 RDX: ffff88801bae9e00 RSI: ffffffff813d162b RDI: 0000000000000005 RBP: ffffc90003d1fb70 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000002 R12: ffffc90003d1f788 R13: ffffc90003d1f790 R14: ffffc90003d18000 R15: ffffc90003d20000 FS: 0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000559b2be07400 CR3: 0000000022c82000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_stack arch/x86/include/asm/stacktrace.h:60 [inline] stack_access_ok+0x1f5/0x270 arch/x86/kernel/unwind_orc.c:393 deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline] unwind_next_frame+0xd9b/0x23a0 arch/x86/kernel/unwind_orc.c:585 arch_stack_walk+0x100/0x170 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x95/0xd0 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:579 poison_slab_object mm/kasan/common.c:240 [inline] __kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2106 [inline] slab_free mm/slub.c:4280 [inline] kfree+0x129/0x390 mm/slub.c:4390 skb_kfree_head net/core/skbuff.c:1096 [inline] skb_free_head+0x110/0x1e0 net/core/skbuff.c:1108 skb_release_data+0x76c/0x990 net/core/skbuff.c:1136 skb_release_all net/core/skbuff.c:1202 [inline] __kfree_skb net/core/skbuff.c:1216 [inline] consume_skb net/core/skbuff.c:1432 [inline] consume_skb+0xd2/0x170 net/core/skbuff.c:1426 batadv_forw_packet_free+0x1f6/0x280 net/batman-adv/send.c:471 batadv_iv_send_outstanding_bat_ogm_packet+0x262/0x8d0 net/batman-adv/bat_iv_ogm.c:1718 process_one_work+0x9a9/0x1ac0 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244