rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4156/1:b..l (detected by 1, t=10502 jiffies, g=10073, q=37 ncpus=2) task:syz-executor.2 state:R running task stack:23912 pid:4156 ppid:3575 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x142d/0x4550 kernel/sched/core.c:6558 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870 irqentry_exit+0x53/0x80 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653 RIP: 0010:__preempt_count_add kernel/rcu/tree.c:717 [inline] RIP: 0010:rcu_is_watching+0x2/0xb0 kernel/rcu/tree.c:720 Code: 44 24 21 02 0f 84 02 ff ff ff e9 6c ff ff ff 48 c7 c7 e0 15 13 8d 4c 89 f6 e8 aa 42 f0 02 e9 2b ff ff ff e8 d0 c2 17 09 41 57 <41> 56 53 65 ff 05 fc 29 8f 7e e8 0f db 17 09 89 c3 83 f8 08 73 76 RSP: 0018:ffffc9000555f068 EFLAGS: 00000202 RAX: 0000000000000002 RBX: ffffea00014ebc80 RCX: ffff888026f20000 RDX: ffff888026f20000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: ffffffff81ecb39d R09: fffffbfff2093845 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000001 R13: 0000000000000000 R14: ffffffff81ecb36c R15: 0000000000000000 rcu_read_lock include/linux/rcupdate.h:792 [inline] page_ext_get+0x56/0x2a0 mm/page_ext.c:157 __set_page_owner+0x32/0x390 mm/page_owner.c:192 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2513 prep_new_page mm/page_alloc.c:2520 [inline] get_page_from_freelist+0x31a1/0x3320 mm/page_alloc.c:4279 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5547 __folio_alloc+0xf/0x30 mm/page_alloc.c:5579 vma_alloc_folio+0x486/0x990 mm/mempolicy.c:2243 shmem_alloc_folio mm/shmem.c:1589 [inline] shmem_alloc_and_acct_folio+0x5a8/0xd50 mm/shmem.c:1613 shmem_get_folio_gfp+0x13f0/0x3470 mm/shmem.c:1941 shmem_get_folio mm/shmem.c:2072 [inline] shmem_write_begin+0x16e/0x4e0 mm/shmem.c:2559 generic_perform_write+0x2fc/0x5e0 mm/filemap.c:3817 __generic_file_write_iter+0x176/0x400 mm/filemap.c:3945 generic_file_write_iter+0xab/0x310 mm/filemap.c:3977 call_write_iter include/linux/fs.h:2265 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x7ae/0xba0 fs/read_write.c:584 ksys_write+0x19c/0x2c0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f5a8887bcaf RSP: 002b:00007f5a873f5e80 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007f5a8887bcaf RDX: 0000000001000000 RSI: 00007f5a7efd6000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000051a4 R10: 0000000020005282 R11: 0000000000000293 R12: 0000000000000003 R13: 00007f5a873f5f80 R14: 00007f5a873f5f40 R15: 00007f5a7efd6000 rcu: rcu_preempt kthread starved for 10546 jiffies! g10073 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:26616 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x142d/0x4550 kernel/sched/core.c:6558 schedule+0xbf/0x180 kernel/sched/core.c:6634 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965 rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706 rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4162 Comm: syz-executor.3 Not tainted 6.1.92-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 RIP: 0010:os_xsave arch/x86/kernel/fpu/xstate.h:194 [inline] RIP: 0010:save_fpregs_to_fpstate+0xba/0x210 arch/x86/kernel/fpu/core.c:118 Code: 11 41 0d 31 ff 89 de e8 a4 1f 58 00 85 db 0f 84 ed 00 00 00 e8 37 1c 58 00 48 89 ef 4c 89 e6 31 d2 e8 0a ad 00 00 48 8d 7d 40 <44> 89 e0 44 89 ea 48 0f ae 37 31 db 31 ff 89 de e8 71 1f 58 00 85 RSP: 0018:ffffc9000b3cf660 EFLAGS: 00000086 RAX: ffffffff81331e9a RBX: 0000000000000001 RCX: ffff88807cb49dc0 RDX: 0000000040000002 RSI: 0000000000000000 RDI: ffff88807cb4b740 RBP: ffff88807cb4b700 R08: ffffffff81331e90 R09: ffffed100f9693b9 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000007 R13: 0000000000000000 R14: ffff88807cb4b6d0 R15: 1ffff1100f9696da FS: 00007fe75e4846c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe75e441f80 CR3: 00000000220f8000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: vkms_vblank_simulate: vblank timer overrun vkms_vblank_simulate: vblank timer overrun hrtimer: interrupt took 932799268 ns vkms_vblank_simulate: vblank timer overrun