==================================================================
BUG: KFENCE: out-of-bounds read in afs_split_string fs/afs/addr_prefs.c:51 [inline]
BUG: KFENCE: out-of-bounds read in afs_proc_addr_prefs_write+0x6ad/0x15d0 fs/afs/addr_prefs.c:415

Out-of-bounds read at 0xffff88823bf9d000 (4096B right of kfence-#205):
 afs_split_string fs/afs/addr_prefs.c:51 [inline]
 afs_proc_addr_prefs_write+0x6ad/0x15d0 fs/afs/addr_prefs.c:415
 proc_simple_write+0x114/0x1b0 fs/proc/generic.c:817
 pde_write fs/proc/inode.c:330 [inline]
 proc_reg_write+0x23d/0x330 fs/proc/inode.c:342
 vfs_write+0x24c/0x1150 fs/read_write.c:677
 ksys_write+0x12b/0x250 fs/read_write.c:731
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

kfence-#205: 0xffff88823bf9c000-0xffff88823bf9c006, size=7, cache=kmalloc-8

allocated by task 7482 on cpu 1 at 150.214638s (0.076701s ago):
 memdup_user_nul+0x2b/0x110 mm/util.c:300
 proc_simple_write+0xc7/0x1b0 fs/proc/generic.c:814
 pde_write fs/proc/inode.c:330 [inline]
 proc_reg_write+0x23d/0x330 fs/proc/inode.c:342
 vfs_write+0x24c/0x1150 fs/read_write.c:677
 ksys_write+0x12b/0x250 fs/read_write.c:731
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 7482 Comm: syz.3.441 Not tainted 6.14.0-rc5-syzkaller-00218-g2a520073e74f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:afs_split_string fs/afs/addr_prefs.c:51 [inline]
RIP: 0010:afs_proc_addr_prefs_write+0x6ad/0x15d0 fs/afs/addr_prefs.c:415
Code: 00 00 00 e8 25 e6 3e fe 48 83 c3 01 48 89 d8 48 89 da 48 c1 e8 03 83 e2 07 42 0f b6 04 38 38 d0 7f 08 84 c0 0f 85 cb 0c 00 00 <44> 0f b6 2b 49 8d bd 20 c8 ce 8c 4d 89 ec 48 89 f8 48 89 fa 48 c1
RSP: 0018:ffffc90003327af0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88823bf9d000 RCX: ffffc9000c9f2000
RDX: 0000000000000000 RSI: ffffffff837af9db RDI: 0000000000000001
RBP: ffffc90003327c90 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff81000130 R12: 00000000000000ad
R13: 0000000000000000 R14: 0000000000000001 R15: dffffc0000000000
FS:  00007fd0b7fc26c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff88823bf9d000 CR3: 000000007de30000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 proc_simple_write+0x114/0x1b0 fs/proc/generic.c:817
 pde_write fs/proc/inode.c:330 [inline]
 proc_reg_write+0x23d/0x330 fs/proc/inode.c:342
 vfs_write+0x24c/0x1150 fs/read_write.c:677
 ksys_write+0x12b/0x250 fs/read_write.c:731
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd0b718d169
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd0b7fc2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fd0b73a5fa0 RCX: 00007fd0b718d169
RDX: 0000000000000006 RSI: 0000000000000000 RDI: 000000000000000c
RBP: 00007fd0b720e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fd0b73a5fa0 R15: 00007ffda1a584b8
 </TASK>
==================================================================
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	00 e8                	add    %ch,%al
   4:	25 e6 3e fe 48       	and    $0x48fe3ee6,%eax
   9:	83 c3 01             	add    $0x1,%ebx
   c:	48 89 d8             	mov    %rbx,%rax
   f:	48 89 da             	mov    %rbx,%rdx
  12:	48 c1 e8 03          	shr    $0x3,%rax
  16:	83 e2 07             	and    $0x7,%edx
  19:	42 0f b6 04 38       	movzbl (%rax,%r15,1),%eax
  1e:	38 d0                	cmp    %dl,%al
  20:	7f 08                	jg     0x2a
  22:	84 c0                	test   %al,%al
  24:	0f 85 cb 0c 00 00    	jne    0xcf5
* 2a:	44 0f b6 2b          	movzbl (%rbx),%r13d <-- trapping instruction
  2e:	49 8d bd 20 c8 ce 8c 	lea    -0x733137e0(%r13),%rdi
  35:	4d 89 ec             	mov    %r13,%r12
  38:	48 89 f8             	mov    %rdi,%rax
  3b:	48 89 fa             	mov    %rdi,%rdx
  3e:	48                   	rex.W
  3f:	c1                   	.byte 0xc1