rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10499 ticks this GP) idle=0a2/1/0x4000000000000002 softirq=11013/11013 fqs=2745 (t=10500 jiffies g=6557 q=204) rcu: rcu_preempt kthread starved for 4981 jiffies! g6557 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29104 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 0 CPU: 0 PID: 8249 Comm: syz-executor.0 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fb/0x318 lib/dump_stack.c:118 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x15a/0x220 kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq+0xe25/0x1ad0 kernel/rcu/tree.c:2271 update_process_times+0x12d/0x180 kernel/time/timer.c:1726 tick_sched_handle kernel/time/tick-sched.c:167 [inline] tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:mod_memcg_page_state+0x2b/0x190 include/linux/memcontrol.h:653 Code: 48 89 e5 41 57 41 56 41 54 53 41 89 f6 48 89 fb e8 da 28 2e 00 48 83 c3 38 48 89 d8 48 c1 e8 03 49 bc 00 00 00 00 00 fc ff df <42> 80 3c 20 00 74 08 48 89 df e8 b6 9f 69 00 48 8b 1b 48 85 db 0f RSP: 0018:ffffc90002627768 EFLAGS: 00000a06 ORIG_RAX: ffffffffffffff13 RAX: 1ffffd400047d16f RBX: ffffea00023e8b78 RCX: ffff8880988ec200 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00023e8b40 RBP: ffffc90002627788 R08: 000000000003a768 R09: fffffbfff120248a R10: fffffbfff120248a R11: 0000000000000000 R12: dffffc0000000000 R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff8880a7c279e8 free_thread_stack+0x168/0x590 kernel/fork.c:280 release_task_stack kernel/fork.c:440 [inline] put_task_stack+0xa3/0x130 kernel/fork.c:451 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256 context_switch kernel/sched/core.c:3388 [inline] __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 preempt_schedule_irq+0xc1/0x140 kernel/sched/core.c:4338 retint_kernel+0x1b/0x2b RIP: 0010:check_memory_region+0x8/0x2e0 mm/kasan/generic.c:191 Code: db 48 c7 c7 63 73 bf 88 4c 89 fe 31 c0 e8 03 8b ad ff eb cf cc cc cc cc cc cc cc cc cc cc cc cc cc cc 55 48 89 e5 41 57 41 56 <41> 55 41 54 53 b0 01 48 85 f6 0f 84 fd 01 00 00 48 89 fb 48 c1 eb RSP: 0018:ffffc900026279e0 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffffffff81cab0ad RBX: 0000000000000003 RCX: ffffffff81cab0ba RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff88808ecd7108 RBP: ffffc900026279f0 R08: ffffffff81cab0a4 R09: ffffed1011d9ae22 R10: ffffed1011d9ae22 R11: 0000000000000000 R12: 000000000000000b R13: dffffc0000000000 R14: ffff88808ecd7108 R15: 00000000ffffffc3 __kasan_check_write+0x14/0x20 mm/kasan/common.c:100 atomic_dec include/asm-generic/atomic-instrumented.h:329 [inline] put_bh include/linux/buffer_head.h:289 [inline] __brelse+0x5a/0xa0 fs/buffer.c:1182 brelse include/linux/buffer_head.h:295 [inline] ext4_xattr_ibody_get+0x5d6/0xa90 fs/ext4/xattr.c:622 ext4_xattr_get+0x115/0x840 fs/ext4/xattr.c:649 ext4_xattr_security_get+0x32/0x40 fs/ext4/xattr_security.c:20 __vfs_getxattr+0x3b7/0x3f0 fs/xattr.c:311 smk_fetch security/smack/smack_lsm.c:294 [inline] smack_d_instantiate+0xaf0/0xd70 security/smack/smack_lsm.c:3459 security_d_instantiate+0xa5/0x100 security/security.c:1874 d_instantiate_new+0x65/0x120 fs/dcache.c:1971 ext4_add_nondir+0x1e9/0x260 fs/ext4/namei.c:2566 ext4_symlink+0x919/0xf60 fs/ext4/namei.c:3344 vfs_symlink+0x36f/0x4f0 fs/namei.c:4123 do_symlinkat+0x187/0x3f0 fs/namei.c:4150 __do_sys_symlink fs/namei.c:4169 [inline] __se_sys_symlink fs/namei.c:4167 [inline] __x64_sys_symlink+0x60/0x70 fs/namei.c:4167 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a3a7 Code: 0f 1f 00 b8 5c 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 6d b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 58 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 4d b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffd51333c58 EFLAGS: 00000202 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000045a3a7 RDX: 00007ffd51333cf3 RSI: 00000000004c00e9 RDI: 00007ffd51333ce0 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000013 R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000001 R13: 00007ffd51333c90 R14: 0000000000000000 R15: 00007ffd51333ca0