rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3267/1:b..l P3268/1:b..l (detected by 0, t=10502 jiffies, g=182521, q=57) task:syz-executor.4 state:R running task stack:29040 pid: 3268 ppid: 16694 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb44/0x5960 kernel/sched/core.c:6287 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:6687 irqentry_exit+0x31/0x80 kernel/entry/common.c:425 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:xa_entry include/linux/xarray.h:1182 [inline] RIP: 0010:xas_descend+0x2a0/0x3b0 lib/xarray.c:204 Code: fd 48 c7 c2 00 16 e7 89 be 9e 04 00 00 48 c7 c7 c0 15 e7 89 c6 05 45 5f 61 09 01 e8 4a bf fb 04 e9 a6 fe ff ff e8 d0 d0 7d fd 5b f4 68 fd 31 ff 41 89 c6 89 c6 e8 6f d9 7d fd 45 85 f6 0f 85 RSP: 0018:ffffc9000bf4f8a8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffffc9000bf4f9a0 RCX: 0000000000000000 RDX: ffff88803472c040 RSI: ffffffff83f852d0 RDI: 0000000000000003 RBP: 000000000000000e R08: 0000000000000000 R09: 0000000000000006 R10: ffffffff83f85126 R11: 000000000000003f R12: ffff888145a576c0 R13: ffff8880218da9c2 R14: 0000000000000000 R15: 0000000000000006 xas_load+0xe5/0x140 lib/xarray.c:240 mapping_get_entry mm/filemap.c:1826 [inline] pagecache_get_page+0x165/0x17c0 mm/filemap.c:1894 find_get_page_flags include/linux/pagemap.h:357 [inline] __find_get_block_slow fs/buffer.c:202 [inline] __find_get_block fs/buffer.c:1308 [inline] __find_get_block+0x4ba/0xdb0 fs/buffer.c:1302 sb_find_get_block include/linux/buffer_head.h:340 [inline] recently_deleted fs/ext4/ialloc.c:689 [inline] find_inode_bit+0x230/0x580 fs/ext4/ialloc.c:731 __ext4_new_inode+0xc64/0x5ba0 fs/ext4/ialloc.c:1066 ext4_symlink+0x489/0xd50 fs/ext4/namei.c:3293 vfs_symlink fs/namei.c:4250 [inline] vfs_symlink+0x479/0x730 fs/namei.c:4235 do_symlinkat+0x261/0x2e0 fs/namei.c:4279 __do_sys_symlink fs/namei.c:4301 [inline] __se_sys_symlink fs/namei.c:4299 [inline] __x64_sys_symlink+0x75/0x90 fs/namei.c:4299 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7efc52814347 RSP: 002b:00007ffcb3ab5078 EFLAGS: 00000206 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007efc52814347 RDX: 00007ffcb3ab5157 RSI: 00007efc5286ef30 RDI: 00007ffcb3ab5140 RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffcb3ab4f10 R10: 00007ffcb3ab4dc7 R11: 0000000000000206 R12: 0000000000000001 R13: 0000000000000001 R14: 0000000000000001 R15: 00007ffcb3ab5140 task:syz-executor.1 state:R running task stack:29472 pid: 3267 ppid: 16695 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb44/0x5960 kernel/sched/core.c:6287 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:6687 irqentry_exit+0x31/0x80 kernel/entry/common.c:425 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lock_acquire+0x16/0x510 kernel/locking/lockdep.c:5593 Code: 6e 8d e8 dd 79 61 00 e9 fb fe ff ff 0f 1f 84 00 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 41 57 41 89 f7 41 56 49 89 fe 41 55 <41> 89 d5 41 54 41 89 cc 55 44 89 c5 53 48 81 ec b0 00 00 00 48 8d RSP: 0018:ffffc9000e6c7a40 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8b97f0e0 RBP: ffff88814818a000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff820962cc R11: 0000000000000000 R12: ffff88814818c000 R13: 0000000000000000 R14: ffffffff8b97f0e0 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:267 [inline] rcu_read_lock include/linux/rcupdate.h:687 [inline] ext4_get_group_desc+0x146/0x500 fs/ext4/balloc.c:284 recently_deleted fs/ext4/ialloc.c:685 [inline] find_inode_bit+0x1c4/0x580 fs/ext4/ialloc.c:731 __ext4_new_inode+0xc64/0x5ba0 fs/ext4/ialloc.c:1066 ext4_symlink+0x489/0xd50 fs/ext4/namei.c:3293 vfs_symlink fs/namei.c:4250 [inline] vfs_symlink+0x479/0x730 fs/namei.c:4235 do_symlinkat+0x261/0x2e0 fs/namei.c:4279 __do_sys_symlink fs/namei.c:4301 [inline] __se_sys_symlink fs/namei.c:4299 [inline] __x64_sys_symlink+0x75/0x90 fs/namei.c:4299 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f8bee651347 RSP: 002b:00007ffe815e8b58 EFLAGS: 00000202 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f8bee651347 RDX: 00007ffe815e8c37 RSI: 00007f8bee6abf30 RDI: 00007ffe815e8c20 RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffe815e89f0 R10: 00007ffe815e88a7 R11: 0000000000000202 R12: 0000000000000001 R13: 0000000000000001 R14: 0000000000000001 R15: 00007ffe815e8c20 rcu: rcu_preempt kthread starved for 10496 jiffies! g182521 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:27184 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb44/0x5960 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x800 kernel/rcu/tree.c:1957 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2130 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 3270 Comm: syz-executor.0 Not tainted 5.15.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation.cold+0x1fb/0x200 kernel/rcu/tree_stall.h:481 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline] check_cpu_stall kernel/rcu/tree_stall.h:729 [inline] rcu_pending kernel/rcu/tree.c:3880 [inline] rcu_sched_clock_irq+0x2125/0x2200 kernel/rcu/tree.c:2599 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_many_cond+0x452/0xc20 kernel/smp.c:969 Code: 0b 00 85 ed 74 4d 48 b8 00 00 00 00 00 fc ff df 4d 89 f4 4c 89 f5 49 c1 ec 03 83 e5 07 49 01 c4 83 c5 03 e8 e0 4b 0b 00 f3 90 <41> 0f b6 04 24 40 38 c5 7c 08 84 c0 0f 85 33 06 00 00 8b 43 08 31 RSP: 0018:ffffc9000e777710 EFLAGS: 00000246 RAX: 0000000000040000 RBX: ffff8880b9d37180 RCX: ffffc90002db9000 RDX: 0000000000040000 RSI: ffffffff816ad7c0 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff816ad7e6 R11: 0000000000000000 R12: ffffed10173a6e31 R13: 0000000000000001 R14: ffff8880b9d37188 R15: 0000000000000001 on_each_cpu_cond_mask+0x56/0xa0 kernel/smp.c:1135 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:929 [inline] text_poke_bp_batch+0x1b3/0x560 arch/x86/kernel/alternative.c:1114 text_poke_bp+0xad/0x110 arch/x86/kernel/alternative.c:1314 arch_static_call_transform+0x48/0x90 arch/x86/kernel/static_call.c:101 __static_call_update+0xcf/0x620 kernel/static_call.c:136 tracepoint_update_call kernel/tracepoint.c:317 [inline] tracepoint_add_func+0x985/0xda0 kernel/tracepoint.c:358 tracepoint_probe_register_prio kernel/tracepoint.c:511 [inline] tracepoint_probe_register+0xa1/0xf0 kernel/tracepoint.c:531 trace_event_reg+0x28f/0x350 kernel/trace/trace_events.c:513 perf_trace_event_reg kernel/trace/trace_event_perf.c:129 [inline] perf_trace_event_init+0x549/0xa20 kernel/trace/trace_event_perf.c:204 perf_trace_init+0x1a0/0x2f0 kernel/trace/trace_event_perf.c:228 perf_tp_event_init+0xa2/0x120 kernel/events/core.c:9761 perf_try_init_event+0x12a/0x560 kernel/events/core.c:11219 perf_init_event kernel/events/core.c:11283 [inline] perf_event_alloc.part.0+0xf16/0x3b10 kernel/events/core.c:11574 perf_event_alloc kernel/events/core.c:11997 [inline] __do_sys_perf_event_open+0x4ae/0x3130 kernel/events/core.c:12095 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fc8444fba39 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fc841a71188 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007fc8445fef60 RCX: 00007fc8444fba39 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200004c0 RBP: 00007fc844555e8f R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd728621ff R14: 00007fc841a71300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: fd std 1: 48 c7 c2 00 16 e7 89 mov $0xffffffff89e71600,%rdx 8: be 9e 04 00 00 mov $0x49e,%esi d: 48 c7 c7 c0 15 e7 89 mov $0xffffffff89e715c0,%rdi 14: c6 05 45 5f 61 09 01 movb $0x1,0x9615f45(%rip) # 0x9615f60 1b: e8 4a bf fb 04 callq 0x4fbbf6a 20: e9 a6 fe ff ff jmpq 0xfffffecb 25: e8 d0 d0 7d fd callq 0xfd7dd0fa * 2a: e8 5b f4 68 fd callq 0xfd68f48a <-- trapping instruction 2f: 31 ff xor %edi,%edi 31: 41 89 c6 mov %eax,%r14d 34: 89 c6 mov %eax,%esi 36: e8 6f d9 7d fd callq 0xfd7dd9aa 3b: 45 85 f6 test %r14d,%r14d 3e: 0f .byte 0xf 3f: 85 .byte 0x85