==================================================================
BUG: KFENCE: use-after-free read in kvm_fastop_exception+0xfdb/0x1089

Use-after-free read at 0xffff88823bd4a020 (in kfence-#164):
 kvm_fastop_exception+0xfdb/0x1089
 d_lookup+0x32/0x70 fs/dcache.c:2370
 lookup_dcache fs/namei.c:1520 [inline]
 __lookup_hash+0x2e/0x240 fs/namei.c:1543
 kern_path_locked+0x2f2/0x490 fs/namei.c:2567
 handle_remove drivers/base/devtmpfs.c:312 [inline]
 handle drivers/base/devtmpfs.c:382 [inline]
 devtmpfs_work_loop+0x264/0x1080 drivers/base/devtmpfs.c:395
 devtmpfsd+0x44/0x50 drivers/base/devtmpfs.c:437
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30

kfence-#164 [0xffff88823bd4a000-0xffff88823bd4afff, size=4096, cache=names_cache] allocated by task 22:
 getname_kernel+0x55/0x2d0 fs/namei.c:226
 kern_path_locked+0xbb/0x490 fs/namei.c:2558
 handle_remove drivers/base/devtmpfs.c:312 [inline]
 handle drivers/base/devtmpfs.c:382 [inline]
 devtmpfs_work_loop+0x264/0x1080 drivers/base/devtmpfs.c:395
 devtmpfsd+0x44/0x50 drivers/base/devtmpfs.c:437
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30

freed by task 22:
 putname fs/namei.c:270 [inline]
 filename_parentat fs/namei.c:2547 [inline]
 kern_path_locked+0x226/0x490 fs/namei.c:2558
 handle_remove drivers/base/devtmpfs.c:312 [inline]
 handle drivers/base/devtmpfs.c:382 [inline]
 devtmpfs_work_loop+0x264/0x1080 drivers/base/devtmpfs.c:395
 devtmpfsd+0x44/0x50 drivers/base/devtmpfs.c:437
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30

CPU: 0 PID: 22 Comm: kdevtmpfs Not tainted 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:kvm_fastop_exception+0xfdb/0x1089
Code: ed e9 23 d1 be f7 49 8d 4d 00 48 83 e1 f8 48 8b 19 41 8d 4d 00 83 e1 07 c1 e1 03 48 d3 eb e9 07 e5 be f7 49 8d 0e 48 83 e1 f8 <4c> 8b 21 41 8d 0e 83 e1 07 c1 e1 03 49 d3 ec e9 cb ed be f7 49 8d
RSP: 0018:ffffc90000dcfa18 EFLAGS: 00010282
RAX: 0000003475736376 RBX: 0000000000000028 RCX: ffff88823bd4a020
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff888073a57388
RBP: 0000000000000005 R08: dffffc0000000000 R09: ffffed100e74ae72
R10: ffffed100e74ae72 R11: 0000000000000000 R12: 00000000a53ad59c
R13: 0000003475736376 R14: ffff88823bd4a020 R15: ffff888073a57388
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff88823bd4a020 CR3: 0000000074ffc000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 d_lookup+0x32/0x70 fs/dcache.c:2370
 lookup_dcache fs/namei.c:1520 [inline]
 __lookup_hash+0x2e/0x240 fs/namei.c:1543
 kern_path_locked+0x2f2/0x490 fs/namei.c:2567
 handle_remove drivers/base/devtmpfs.c:312 [inline]
 handle drivers/base/devtmpfs.c:382 [inline]
 devtmpfs_work_loop+0x264/0x1080 drivers/base/devtmpfs.c:395
 devtmpfsd+0x44/0x50 drivers/base/devtmpfs.c:437
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30
==================================================================
----------------
Code disassembly (best guess):
   0:	ed                   	in     (%dx),%eax
   1:	e9 23 d1 be f7       	jmpq   0xf7bed129
   6:	49 8d 4d 00          	lea    0x0(%r13),%rcx
   a:	48 83 e1 f8          	and    $0xfffffffffffffff8,%rcx
   e:	48 8b 19             	mov    (%rcx),%rbx
  11:	41 8d 4d 00          	lea    0x0(%r13),%ecx
  15:	83 e1 07             	and    $0x7,%ecx
  18:	c1 e1 03             	shl    $0x3,%ecx
  1b:	48 d3 eb             	shr    %cl,%rbx
  1e:	e9 07 e5 be f7       	jmpq   0xf7bee52a
  23:	49 8d 0e             	lea    (%r14),%rcx
  26:	48 83 e1 f8          	and    $0xfffffffffffffff8,%rcx
* 2a:	4c 8b 21             	mov    (%rcx),%r12 <-- trapping instruction
  2d:	41 8d 0e             	lea    (%r14),%ecx
  30:	83 e1 07             	and    $0x7,%ecx
  33:	c1 e1 03             	shl    $0x3,%ecx
  36:	49 d3 ec             	shr    %cl,%r12
  39:	e9 cb ed be f7       	jmpq   0xf7beee09
  3e:	49                   	rex.WB
  3f:	8d                   	.byte 0x8d