rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P393/1:b..l
	(detected by 1, t=10502 jiffies, g=422177, q=1936)
task:syz-executor.1  state:R  running task     stack:28176 pid:  393 ppid:  5540 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:4940 [inline]
 __schedule+0xb72/0x1460 kernel/sched/core.c:6287
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6687
 irqentry_exit+0x56/0x90 kernel/entry/common.c:425
 asm_sysvec_apic_timer_interrupt+0x12/0x20
RIP: 0010:__preempt_count_add kernel/rcu/tree.c:1117 [inline]
RIP: 0010:rcu_is_watching+0x4/0xb0 kernel/rcu/tree.c:1120
Code: 5d 41 5e 41 5f 5d c3 e8 fa 52 8c 08 41 f7 c4 00 02 00 00 75 b4 eb b3 e8 ca 52 8c 08 66 2e 0f 1f 84 00 00 00 00 00 41 57 41 56 <53> 65 83 05 0b bc 93 7e 01 e8 6e 65 8c 08 89 c3 83 f8 08 73 7e 49
RSP: 0018:ffffc90005807908 EFLAGS: 00000246
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffff888047461c80
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8880b9c32508
RBP: ffff8880269a6ac8 R08: dffffc0000000000 R09: ffffed10173864a2
R10: ffffed10173864a2 R11: 0000000000000000 R12: 0000000000000001
R13: ffff88814850e678 R14: dffffc0000000000 R15: 1ffff110290a1ccf
 rcu_read_lock_held_common kernel/rcu/update.c:108 [inline]
 rcu_read_lock_held+0x11/0x40 kernel/rcu/update.c:309
 ext4_get_group_desc+0x1df/0x440 fs/ext4/balloc.c:284
 recently_deleted fs/ext4/ialloc.c:685 [inline]
 find_inode_bit+0x1f5/0x560 fs/ext4/ialloc.c:731
 __ext4_new_inode+0x102d/0x5650 fs/ext4/ialloc.c:1066
 ext4_symlink+0x4e1/0xfa0 fs/ext4/namei.c:3293
 vfs_symlink+0x379/0x590 fs/namei.c:4250
 do_symlinkat+0x22c/0x650 fs/namei.c:4279
 __do_sys_symlink fs/namei.c:4301 [inline]
 __se_sys_symlink fs/namei.c:4299 [inline]
 __x64_sys_symlink+0x7a/0x90 fs/namei.c:4299
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fb6cf370347
RSP: 002b:00007ffd36243998 EFLAGS: 00000202 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb6cf370347
RDX: 00007ffd36243a77 RSI: 00007fb6cf3caf30 RDI: 00007ffd36243a60
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffd36243830
R10: 00007ffd362436e7 R11: 0000000000000202 R12: 0000000000000001
R13: 0000000000000001 R14: 0000000000000001 R15: 00007ffd36243a60
----------------
Code disassembly (best guess):
   0:	5d                   	pop    %rbp
   1:	41 5e                	pop    %r14
   3:	41 5f                	pop    %r15
   5:	5d                   	pop    %rbp
   6:	c3                   	retq
   7:	e8 fa 52 8c 08       	callq  0x88c5306
   c:	41 f7 c4 00 02 00 00 	test   $0x200,%r12d
  13:	75 b4                	jne    0xffffffc9
  15:	eb b3                	jmp    0xffffffca
  17:	e8 ca 52 8c 08       	callq  0x88c52e6
  1c:	66 2e 0f 1f 84 00 00 	nopw   %cs:0x0(%rax,%rax,1)
  23:	00 00 00
  26:	41 57                	push   %r15
  28:	41 56                	push   %r14
* 2a:	53                   	push   %rbx <-- trapping instruction
  2b:	65 83 05 0b bc 93 7e 	addl   $0x1,%gs:0x7e93bc0b(%rip)        # 0x7e93bc3e
  32:	01
  33:	e8 6e 65 8c 08       	callq  0x88c65a6
  38:	89 c3                	mov    %eax,%ebx
  3a:	83 f8 08             	cmp    $0x8,%eax
  3d:	73 7e                	jae    0xbd
  3f:	49                   	rex.WB