rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=e4e/1/0x4000000000000000 softirq=24957/24957 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): (detected by 0, t=10502 jiffies, g=36349, q=110) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 14741 Comm: kworker/u4:0 Not tainted 5.11.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:queued_write_lock_slowpath+0x131/0x270 kernel/locking/qrwlock.c:77 Code: 00 00 00 00 fc ff df 49 01 c7 41 83 c6 03 41 0f b6 07 41 38 c6 7c 08 84 c0 0f 85 fe 00 00 00 8b 03 3d 00 01 00 00 74 19 f3 90 <41> 0f b6 07 41 38 c6 7c ec 84 c0 74 e8 48 89 df e8 2a c1 5b 00 eb RSP: 0018:ffffc900016ffcb8 EFLAGS: 00000006 RAX: 0000000000000300 RBX: ffffffff8b00a080 RCX: ffffffff815947ba RDX: fffffbfff1601411 RSI: 0000000000000004 RDI: ffffffff8b00a080 RBP: 00000000000000ff R08: 0000000000000001 R09: ffffffff8b00a083 R10: fffffbfff1601410 R11: 0000000000000000 R12: 1ffff920002dff98 R13: ffffffff8b00a084 R14: 0000000000000003 R15: fffffbfff1601410 FS: 0000000000000000(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000074a4d8 CR3: 000000002b9f8000 CR4: 0000000000350ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: queued_write_lock include/asm-generic/qrwlock.h:95 [inline] do_raw_write_lock+0x1ce/0x280 kernel/locking/spinlock_debug.c:207 exit_notify kernel/exit.c:667 [inline] do_exit+0xcaa/0x2ae0 kernel/exit.c:845 call_usermodehelper_exec_async+0x413/0x580 kernel/umh.c:123 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 task:syz-executor.2 state:R running task stack:28664 pid:14737 ppid: 8636 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:4313 [inline] __schedule+0x90c/0x21a0 kernel/sched/core.c:5064 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:5326 irqentry_exit_cond_resched kernel/entry/common.c:393 [inline] irqentry_exit_cond_resched kernel/entry/common.c:385 [inline] irqentry_exit+0x7a/0xa0 kernel/entry/common.c:423 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:628 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:85 [inline] RIP: 0010:lock_acquire kernel/locking/lockdep.c:5440 [inline] RIP: 0010:lock_acquire+0x2c7/0x740 kernel/locking/lockdep.c:5402 Code: 48 c7 c7 80 a1 4b 89 48 83 c4 20 e8 53 23 93 07 b8 ff ff ff ff 65 0f c1 05 76 71 a9 7e 83 f8 01 0f 85 36 03 00 00 ff 34 24 9d 3a fe ff ff 65 ff 05 dd 5f a9 7e 48 8b 05 76 fc 82 0b e8 71 18 RSP: 0018:ffffc9000207f830 EFLAGS: 00000246 RAX: 0000000000000001 RBX: 1ffff9200040ff08 RCX: 0000000000000001 RDX: 1ffff1100db29820 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8ebda7a7 R10: fffffbfff1d7b4f4 R11: 0000000000000001 R12: 0000000000000002 R13: ffffffff8b363860 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:253 [inline] rcu_read_lock include/linux/rcupdate.h:642 [inline] is_bpf_text_address+0x36/0x160 kernel/bpf/core.c:700 kernel_text_address kernel/extable.c:151 [inline] kernel_text_address+0xbd/0xf0 kernel/extable.c:120 __kernel_text_address+0x9/0x30 kernel/extable.c:105 unwind_get_return_address arch/x86/kernel/unwind_orc.c:318 [inline] unwind_get_return_address+0x51/0x90 arch/x86/kernel/unwind_orc.c:313 arch_stack_walk+0x93/0xe0 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:121 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:356 ____kasan_slab_free+0xe1/0x110 mm/kasan/common.c:362 kasan_slab_free include/linux/kasan.h:188 [inline] slab_free_hook mm/slub.c:1547 [inline] slab_free_freelist_hook+0x5d/0x150 mm/slub.c:1580 slab_free mm/slub.c:3142 [inline] kmem_cache_free+0x82/0x350 mm/slub.c:3158 putname+0xe1/0x120 fs/namei.c:259 filename_create+0x22e/0x490 fs/namei.c:3492 user_path_create fs/namei.c:3527 [inline] do_symlinkat+0xe1/0x2c0 fs/namei.c:3982 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45df47 RSP: 002b:00007ffdf40cf888 EFLAGS: 00000206 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000045df47 RDX: 00007ffdf40cf943 RSI: 00000000004c3c8c RDI: 00007ffdf40cf930 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000013 R10: 0000000000000075 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10502 jiffies! g36349 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:28744 pid: 11 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4313 [inline] __schedule+0x90c/0x21a0 kernel/sched/core.c:5064 schedule+0xcf/0x270 kernel/sched/core.c:5143 schedule_timeout+0x148/0x250 kernel/time/timer.c:1878 rcu_gp_fqs_loop kernel/rcu/tree.c:1940 [inline] rcu_gp_kthread+0xbbe/0x1d70 kernel/rcu/tree.c:2113 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296