rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=02a4/1/0x4000000000000000 softirq=73039/73039 fqs=100 rcu: (detected by 0, t=10502 jiffies, g=73229, q=624 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 14105 Comm: syz.3.3364 Not tainted 6.13.0-rc3-syzkaller-00301-gbcde95ce32b6 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:__lock_acquire+0x364/0x2100 kernel/locking/lockdep.c:5161 Code: 30 00 74 17 48 89 df e8 4a 99 88 00 48 8b 7c 24 08 48 be 00 00 00 00 00 fc ff df 4c 89 23 4a 8d 5c ef 10 48 89 d8 48 c1 e8 03 <80> 3c 30 00 74 17 48 89 df e8 1e 99 88 00 48 8b 7c 24 08 48 be 00 RSP: 0018:ffffc90000a18930 EFLAGS: 00000806 RAX: 1ffff11004bdc528 RBX: ffff888025ee2940 RCX: ffffffff9a377903 RDX: 0000000000000002 RSI: dffffc0000000000 RDI: ffff888025ee28e0 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001 R10: dffffc0000000000 R11: fffffbfff2030a6f R12: ffffffff84c0c158 R13: 000000000000000a R14: 0000000000000000 R15: ffffffff9a5d08a0 FS: 00007f1211b426c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000202b7030 CR3: 000000005297a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 debug_object_deactivate+0x158/0x390 lib/debugobjects.c:873 debug_hrtimer_deactivate kernel/time/hrtimer.c:433 [inline] debug_deactivate+0x1b/0x220 kernel/time/hrtimer.c:475 __run_hrtimer kernel/time/hrtimer.c:1707 [inline] __hrtimer_run_queues+0x305/0xd30 kernel/time/hrtimer.c:1803 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1865 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:36 [inline] RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline] RIP: 0010:lock_release+0x80/0xa30 kernel/locking/lockdep.c:5860 Code: f0 d5 7a 81 4c 8d 64 24 60 49 c1 ec 03 48 b8 f1 f1 f1 f1 04 f2 00 f2 4b 89 04 3c 48 b8 f2 f2 00 f3 f3 f3 f3 f3 4b 89 44 3c 08 <0f> 1f 44 00 00 65 8b 05 10 fe 88 7e 83 f8 08 0f 83 fe 05 00 00 89 RSP: 0018:ffffc90004607940 EFLAGS: 00000a02 RAX: f3f3f3f3f300f2f2 RBX: 0000000000000000 RCX: ffff888025ee28d8 RDX: dffffc0000000000 RSI: ffffffff81eaec9a RDI: ffff8880217ff3e0 RBP: ffffc90004607a70 R08: ffffffff942708b7 R09: 1ffffffff284e116 R10: dffffc0000000000 R11: fffffbfff284e117 R12: 1ffff920008c0f34 R13: ffffffff81eaec9a R14: 1ffff920008c0f7c R15: dffffc0000000000 do_recvmmsg+0x59c/0xab0 net/socket.c:2946 __sys_recvmmsg net/socket.c:3014 [inline] __do_sys_recvmmsg net/socket.c:3037 [inline] __se_sys_recvmmsg net/socket.c:3030 [inline] __x64_sys_recvmmsg+0x199/0x250 net/socket.c:3030 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1210d85d29 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1211b42038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f1210f75fa0 RCX: 00007f1210d85d29 RDX: 0000000004000210 RSI: 0000000020001740 RDI: 0000000000000003 RBP: 00007f1210e01aa8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f1210f75fa0 R15: 00007ffdb1630528 rcu: rcu_preempt kthread starved for 10000 jiffies! g73229 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:25976 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x17fb/0x4be0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6848 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 52 Comm: kworker/u8:3 Not tainted 6.13.0-rc3-syzkaller-00301-gbcde95ce32b6 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: writeback wb_workfn (flush-8:0) RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x19f3/0x2c60 kernel/smp.c:884 Code: 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 56 e9 0b 00 41 83 e4 01 49 bc 00 00 00 00 00 fc ff df 75 07 e8 01 e5 0b 00 eb 38 f3 90 <42> 0f b6 04 23 84 c0 75 11 41 f7 45 00 01 00 00 00 74 1e e8 e5 e4 RSP: 0018:ffffc90000bc5fc0 EFLAGS: 00000293 RAX: ffffffff81938efb RBX: 1ffff110170e88b9 RCX: ffff88801e2b3c00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000bc61c0 R08: ffffffff81938eca R09: 1ffff92000178be8 R10: dffffc0000000000 R11: ffffffff814d61f0 R12: dffffc0000000000 R13: ffff8880b87445c8 R14: ffff8880b863f940 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555938585c8 CR3: 00000000119a2000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1051 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:939 [inline] flush_tlb_mm_range+0x329/0x5c0 arch/x86/mm/tlb.c:1025 flush_tlb_page arch/x86/include/asm/tlbflush.h:254 [inline] ptep_clear_flush+0x11a/0x170 mm/pgtable-generic.c:101 page_vma_mkclean_one+0x58a/0x9a0 mm/rmap.c:1051 page_mkclean_one+0x272/0x350 mm/rmap.c:1092 rmap_walk_file+0x502/0x780 mm/rmap.c:2708 rmap_walk mm/rmap.c:2726 [inline] folio_mkclean+0x252/0x370 mm/rmap.c:1124 folio_clear_dirty_for_io+0x219/0x950 mm/page-writeback.c:3033 mpage_submit_folio+0x84/0x340 fs/ext4/inode.c:1913 mpage_process_page_bufs+0x6d1/0x9d0 fs/ext4/inode.c:2045 mpage_prepare_extent_to_map+0xecb/0x1860 fs/ext4/inode.c:2546 ext4_do_writepages+0xc2a/0x3df0 fs/ext4/inode.c:2688 ext4_writepages+0x213/0x3c0 fs/ext4/inode.c:2824 do_writepages+0x35f/0x880 mm/page-writeback.c:2702 __writeback_single_inode+0x14f/0x10d0 fs/fs-writeback.c:1680 writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2047 wb_writeback+0x427/0xb80 fs/fs-writeback.c:2158 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline] wb_do_writeback fs/fs-writeback.c:2315 [inline] wb_workfn+0xb94/0x1080 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244