INFO: task syz.3.315:8648 blocked for more than 143 seconds. Not tainted 6.15.0-rc6-syzkaller-00188-gfee3e843b309 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.315 state:D stack:28808 pid:8648 tgid:8647 ppid:8157 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x168f/0x4c70 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 wb_wait_for_completion+0x15f/0x260 fs/fs-writeback.c:216 sync_inodes_sb+0x1bb/0xa10 fs/fs-writeback.c:2833 iterate_supers+0xb8/0x180 fs/super.c:934 ksys_sync+0x94/0x150 fs/sync.c:102 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f09b4b8e969 RSP: 002b:00007f09b5abb038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f09b4db5fa0 RCX: 00007f09b4b8e969 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f09b4db5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f09b4db5fa0 R15: 00007ffc14f12128 INFO: task syz.3.315:8649 blocked for more than 144 seconds. Not tainted 6.15.0-rc6-syzkaller-00188-gfee3e843b309 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.315 state:D stack:28952 pid:8649 tgid:8647 ppid:8157 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x168f/0x4c70 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1176 __down_write_common kernel/locking/rwsem.c:1304 [inline] __down_write kernel/locking/rwsem.c:1313 [inline] down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1578 bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2831 iterate_supers+0xb8/0x180 fs/super.c:934 ksys_sync+0x94/0x150 fs/sync.c:102 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f09b4b8e969 RSP: 002b:00007f09b5a9a038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f09b4db6080 RCX: 00007f09b4b8e969 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f09b4db6080 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f09b4db6080 R15: 00007ffc14f12128 INFO: task syz.3.315:8650 blocked for more than 144 seconds. Not tainted 6.15.0-rc6-syzkaller-00188-gfee3e843b309 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.315 state:D stack:28952 pid:8650 tgid:8647 ppid:8157 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x168f/0x4c70 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x165/0x360 kernel/sched/core.c:6860 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1176 __down_write_common kernel/locking/rwsem.c:1304 [inline] __down_write kernel/locking/rwsem.c:1313 [inline] down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1578 bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2831 iterate_supers+0xb8/0x180 fs/super.c:934 ksys_sync+0x94/0x150 fs/sync.c:102 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f09b4b8e969 RSP: 002b:00007f09b5a79038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f09b4db6160 RCX: 00007f09b4b8e969 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f09b4db6160 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f09b4db6160 R15: 00007ffc14f12128 Showing all locks held in the system: 6 locks held by kworker/u8:1/13: 1 lock held by khungtaskd/31: #0: ffffffff8df3dce0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df3dce0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8df3dce0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764 1 lock held by udevd/5192: 2 locks held by getty/5582: #0: ffff88803093a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002ffe2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 2 locks held by udevd/5829: 1 lock held by syz-executor/8059: #0: ffff88806c6e60e0 (&type->s_umount_key#63){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff88806c6e60e0 (&type->s_umount_key#63){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88806c6e60e0 (&type->s_umount_key#63){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 2 locks held by syz.3.315/8648: #0: ffff88806c6e60e0 (&type->s_umount_key#63){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88806c6e60e0 (&type->s_umount_key#63){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 #1: ffff888143b107d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff888143b107d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2831 2 locks held by syz.3.315/8649: #0: ffff88806c6e60e0 (&type->s_umount_key#63){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88806c6e60e0 (&type->s_umount_key#63){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 #1: ffff888143b107d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff888143b107d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2831 2 locks held by syz.3.315/8650: #0: ffff88806c6e60e0 (&type->s_umount_key#63){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88806c6e60e0 (&type->s_umount_key#63){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 #1: ffff888143b107d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff888143b107d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2831 2 locks held by syz-executor/8901: #0: ffffffff8e66cda8 (bio_slab_lock){+.+.}-{4:4}, at: bio_put_slab block/bio.c:140 [inline] #0: ffffffff8e66cda8 (bio_slab_lock){+.+.}-{4:4}, at: bioset_exit+0x44a/0x690 block/bio.c:1664 #1: ffffffff8df43680 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570 kernel/rcu/tree.c:3774 1 lock held by syz.5.387/9763: #0: ffff88806c6e60e0 (&type->s_umount_key#63){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88806c6e60e0 (&type->s_umount_key#63){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc6-syzkaller-00188-gfee3e843b309 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline] watchdog+0xfee/0x1030 kernel/hung_task.c:437 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 153 Comm: kworker/u8:5 Not tainted 6.15.0-rc6-syzkaller-00188-gfee3e843b309 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:its_return_thunk+0x0/0x10 arch/x86/lib/retpoline.S:411 Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 e9 0b 07 e1 f5 cc RSP: 0018:ffffc90002ea7408 EFLAGS: 00000086 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 8da472915386ff00 RDX: 0000000000000000 RSI: ffff888020f6e590 RDI: ffff888020f6da00 RBP: ffffffff8171ca05 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8171ca05 R12: 0000000000000002 R13: ffffffff8df3dce0 R14: 0000000000000000 R15: 0000000000000246 FS: 0000000000000000(0000) GS:ffff8881261f9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa1868a5e9c CR3: 000000003282e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4327 [inline] __kmalloc_node_track_caller_noprof+0x271/0x4e0 mm/slub.c:4346 kmalloc_reserve+0x136/0x290 net/core/skbuff.c:599 __alloc_skb+0x142/0x2d0 net/core/skbuff.c:668 alloc_skb include/linux/skbuff.h:1340 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline] nsim_dev_trap_report_work+0x29a/0xb80 drivers/net/netdevsim/dev.c:851 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245