rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...0: (2 ticks this GP) idle=467/1/0x4000000000000000 softirq=10119/10119 fqs=2099 (detected by 1, t=10503 jiffies, g=11561, q=1937) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 1157 Comm: kworker/u4:3 Not tainted 5.15.189-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: writeback wb_workfn (flush-8:0) RIP: 0010:hlock_class kernel/locking/lockdep.c:197 [inline] RIP: 0010:__lock_acquire+0x12e1/0x7c60 kernel/locking/lockdep.c:5009 Code: 07 89 c3 81 e3 ff 1f 00 00 c1 e8 03 25 f8 03 00 00 48 8d b8 c0 70 fb 8f be 08 00 00 00 e8 67 1b 60 00 48 0f a3 1d 2f 63 9f 0e <73> 1a 48 8d 04 5b c1 e0 06 48 8d 98 80 ef 93 8f 49 b8 00 00 00 00 RSP: 0018:ffffc900000078c0 EFLAGS: 00000057 RAX: 0000000000000101 RBX: 0000000000000a10 RCX: ffffffff815c0d89 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ffb7200 RBP: ffffc90000007b10 R08: dffffc0000000000 R09: fffffbfff1ff6e41 R10: fffffbfff1ff6e41 R11: 1ffffffff1ff6e40 R12: 00000000a777bcad R13: ffff888021880000 R14: 00000000bf3edeec R15: ffff888021880bd8 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007feb2874dbac CR3: 000000002a678000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] advance_sched+0x47/0x940 net/sched/sch_taprio.c:716 __run_hrtimer kernel/time/hrtimer.c:1690 [inline] __hrtimer_run_queues+0x53d/0xc40 kernel/time/hrtimer.c:1754 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:instrument_atomic_read include/linux/instrumented.h:71 [inline] RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline] RIP: 0010:lock_page_memcg+0x20c/0x410 mm/memcontrol.c:2062 Code: ff 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 f6 44 24 41 02 0f 85 f9 00 00 00 f7 c3 00 02 00 00 74 01 fb 4d 8d af 80 10 00 00 <4c> 89 ef be 04 00 00 00 e8 67 95 fb ff 4c 89 e8 48 c1 e8 03 48 b9 RSP: 0018:ffffc90004d66a00 EFLAGS: 00000206 RAX: 83ff943024c79f00 RBX: 0000000000000286 RCX: 83ff943024c79f00 RDX: dffffc0000000000 RSI: ffffffff8a0b15c0 RDI: ffffffff8a599340 RBP: ffffc90004d66ad0 R08: dffffc0000000000 R09: fffffbfff1ff6e31 R10: fffffbfff1ff6e31 R11: 1ffffffff1ff6e30 R12: ffff888016a8c670 R13: ffff888016a8d080 R14: ffffea0001c6ebf8 R15: ffff888016a8c000 __test_set_page_writeback+0x9e/0xe70 mm/page-writeback.c:2844 ext4_bio_write_page+0x293/0x1f90 fs/ext4/page-io.c:-1 mpage_submit_page+0x17a/0x210 fs/ext4/inode.c:2113 mpage_process_page_bufs+0x6d8/0x8b0 fs/ext4/inode.c:2227 mpage_prepare_extent_to_map+0xb7d/0xf70 fs/ext4/inode.c:2655 ext4_writepages+0xa09/0x2d20 fs/ext4/inode.c:2783 do_writepages+0x48d/0x6d0 mm/page-writeback.c:2386 __writeback_single_inode+0x153/0xda0 fs/fs-writeback.c:1647 writeback_sb_inodes+0x9fe/0x1610 fs/fs-writeback.c:1930 __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2001 wb_writeback+0x455/0xb90 fs/fs-writeback.c:2106 wb_check_old_data_flush fs/fs-writeback.c:2206 [inline] wb_do_writeback fs/fs-writeback.c:2259 [inline] wb_workfn+0xaaa/0xe60 fs/fs-writeback.c:2288 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287