syzbot

loop0: detected capacity change from 0 to 64
BFS-fs: bfs_fill_super(): loop0 is unclean, continuing
Unable to handle kernel paging request at virtual address dfff800000000005
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
Mem abort info:
  ESR = 0x0000000096000005
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x05: level 1 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[dfff800000000005] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1]  SMP
Modules linked in:
CPU: 1 UID: 0 PID: 6719 Comm: syz.0.17 Not tainted 6.17.0-rc1-syzkaller-g8f5ae30d69d7 #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : bfs_move_block fs/bfs/file.c:43 [inline]
pc : bfs_move_blocks fs/bfs/file.c:57 [inline]
pc : bfs_get_block+0x498/0x9d4 fs/bfs/file.c:126
lr : __getblk include/linux/buffer_head.h:380 [inline]
lr : sb_getblk include/linux/buffer_head.h:386 [inline]
lr : bfs_move_block fs/bfs/file.c:42 [inline]
lr : bfs_move_blocks fs/bfs/file.c:57 [inline]
lr : bfs_get_block+0x470/0x9d4 fs/bfs/file.c:126
sp : ffff8000a3d973f0
x29: ffff8000a3d97460 x28: ffff0000c70be160 x27: dfff800000000000
x26: 0000000000000028 x25: ffff0000e3808528 x24: 0000000000000000
x23: ffff0000c70be018 x22: ffff0000c176e828 x21: 1fffe00018e17c2c
x20: 0000000000000200 x19: 000000000000001b x18: 00000000ffffffff
x17: ffff800093507000 x16: ffff800080535980 x15: 0000000000000001
x14: 1fffffbff878c87e x13: 0000000000000000 x12: 0000000000000000
x11: ffff7fbff878c87f x10: 0000000000ff0100 x9 : 0000000000000000
x8 : 0000000000000005 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000020 x4 : 0000000000000008 x3 : ffff800080e6d698
x2 : 0000000000000001 x1 : 0000000000000040 x0 : 0000000000000000
Call trace:
 bfs_move_block fs/bfs/file.c:43 [inline] (P)
 bfs_move_blocks fs/bfs/file.c:57 [inline] (P)
 bfs_get_block+0x498/0x9d4 fs/bfs/file.c:126 (P)
 __block_write_begin_int+0x53c/0x15e8 fs/buffer.c:2145
 block_write_begin+0xa0/0x128 fs/buffer.c:2256
 bfs_write_begin+0x48/0xec fs/bfs/file.c:180
 generic_perform_write+0x244/0x7bc mm/filemap.c:4175
 __generic_file_write_iter+0xfc/0x204 mm/filemap.c:4292
 generic_file_write_iter+0x10c/0x47c mm/filemap.c:4318
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x540/0xa3c fs/read_write.c:686
 ksys_write+0x120/0x210 fs/read_write.c:738
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __arm64_sys_write+0x7c/0x90 fs/read_write.c:746
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x180 arch/arm64/kernel/entry-common.c:879
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
Code: 97e6ba62 9100a31a f94012d4 d343ff48 (387b6908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	97e6ba62 	bl	0xffffffffff9ae988
   4:	9100a31a 	add	x26, x24, #0x28
   8:	f94012d4 	ldr	x20, [x22, #32]
   c:	d343ff48 	lsr	x8, x26, #3
* 10:	387b6908 	ldrb	w8, [x8, x27] <-- trapping instruction