rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12/2:b..l P5567/1:b..l rcu: (detected by 0, t=10502 jiffies, g=15901, q=573 ncpus=2) task:syz-executor.3 state:R running task stack:27168 pid:5567 tgid:5567 ppid:5097 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5408 [inline] __schedule+0xf15/0x5d00 kernel/sched/core.c:6745 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7067 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x1f2/0x560 kernel/locking/lockdep.c:5722 Code: c1 05 9a af 96 7e 83 f8 01 0f 85 ea 02 00 00 9c 58 f6 c4 02 0f 85 d5 02 00 00 48 85 ed 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 RSP: 0018:ffffc90003207710 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff92000640ee4 RCX: 00000000d439196c RDX: 0000000000000001 RSI: ffffffff8b2cb0e0 RDI: ffffffff8b900000 RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff284d658 R10: ffffffff9426b2c7 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8dbb18e0 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:329 [inline] rcu_read_lock include/linux/rcupdate.h:781 [inline] page_ext_get+0x3a/0x310 mm/page_ext.c:521 __page_table_check_zero+0xc4/0x360 mm/page_table_check.c:142 page_table_check_alloc include/linux/page_table_check.h:33 [inline] post_alloc_hook+0x2c0/0x350 mm/page_alloc.c:1469 prep_new_page mm/page_alloc.c:1476 [inline] get_page_from_freelist+0x136a/0x2df0 mm/page_alloc.c:3402 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4660 alloc_pages_mpol_noprof+0x275/0x610 mm/mempolicy.c:2265 vm_area_alloc_pages mm/vmalloc.c:3566 [inline] __vmalloc_area_node mm/vmalloc.c:3642 [inline] __vmalloc_node_range_noprof+0xa6a/0x1520 mm/vmalloc.c:3823 vmalloc_user_noprof+0x6b/0x90 mm/vmalloc.c:3977 kcov_ioctl+0x4f/0x730 kernel/kcov.c:705 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f45fb47cc4b RSP: 002b:00007fff1c9b0fa0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f45fb47cc4b RDX: 0000000000040000 RSI: ffffffff80086301 RDI: 00000000000000dc RBP: 00007f45fb5b4358 R08: 00000000000000da R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff1c9b16e8 R13: 0000000000000003 R14: 00007f45fb5b4358 R15: 0000000000000004 task:kworker/u8:1 state:R running task stack:24128 pid:12 tgid:12 ppid:2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:2) Call Trace: context_switch kernel/sched/core.c:5408 [inline] __schedule+0xf15/0x5d00 kernel/sched/core.c:6745 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7067 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x1f2/0x560 kernel/locking/lockdep.c:5722 Code: c1 05 9a af 96 7e 83 f8 01 0f 85 ea 02 00 00 9c 58 f6 c4 02 0f 85 d5 02 00 00 48 85 ed 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 RSP: 0018:ffffc90000116e58 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff92000022dcd RCX: 000000002e3630dc RDX: 0000000000000001 RSI: ffffffff8b2cb0e0 RDI: ffffffff8b900000 RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff284d658 R10: ffffffff9426b2c7 R11: 0000000000000004 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8dbb18e0 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:329 [inline] rcu_read_lock include/linux/rcupdate.h:781 [inline] percpu_ref_get_many include/linux/percpu-refcount.h:202 [inline] percpu_ref_get include/linux/percpu-refcount.h:222 [inline] blkg_get block/blk-cgroup.h:324 [inline] bio_associate_blkg_from_css block/blk-cgroup.c:2083 [inline] bio_associate_blkg_from_css+0x441/0x13e0 block/blk-cgroup.c:2074 bio_associate_blkg block/blk-cgroup.c:2112 [inline] bio_associate_blkg+0x10c/0x2a0 block/blk-cgroup.c:2098 bio_init+0x2ae/0x5a0 block/bio.c:265 bio_alloc_bioset+0x4e0/0x8b0 block/bio.c:578 bio_alloc include/linux/bio.h:437 [inline] __mpage_writepage+0xea5/0x1790 fs/mpage.c:603 write_cache_pages+0xb0/0x130 mm/page-writeback.c:2591 mpage_writepages+0xcf/0x180 fs/mpage.c:673 udf_writepages+0x86/0xe0 fs/udf/inode.c:207 do_writepages+0x1a3/0x7f0 mm/page-writeback.c:2634 __writeback_single_inode+0x163/0xf90 fs/fs-writeback.c:1651 writeback_sb_inodes+0x611/0x1150 fs/fs-writeback.c:1947 __writeback_inodes_wb+0xff/0x2e0 fs/fs-writeback.c:2018 wb_writeback+0x721/0xb50 fs/fs-writeback.c:2129 wb_check_background_flush fs/fs-writeback.c:2199 [inline] wb_do_writeback fs/fs-writeback.c:2287 [inline] wb_workfn+0x8c4/0xf40 fs/fs-writeback.c:2314 process_one_work+0x9fb/0x1b60 kernel/workqueue.c:3231 process_scheduled_works kernel/workqueue.c:3312 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: rcu_preempt kthread starved for 10218 jiffies! g15901 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:27680 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5408 [inline] __schedule+0xf15/0x5d00 kernel/sched/core.c:6745 __schedule_loop kernel/sched/core.c:6822 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6837 schedule_timeout+0x136/0x2a0 kernel/time/timer.c:2581 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2000 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2202 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline] NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt+0x1a/0x20 drivers/acpi/processor_idle.c:112