syzbot

BTRFS info (device loop0): ignoring bad roots
BTRFS info (device loop0): disabling log replay at mount time
BTRFS info (device loop0): using free space tree
BTRFS info (device loop0: state C): scrub: started on devid 1
Unable to handle kernel paging request at virtual address dfff800000000041
KASAN: null-ptr-deref in range [0x0000000000000208-0x000000000000020f]
Mem abort info:
  ESR = 0x0000000096000006
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x06: level 2 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000006
  CM = 0, WnR = 0
[dfff800000000041] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 4463 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : btrfs_lookup_csums_range+0xb0/0xdf0 fs/btrfs/file-item.c:518
lr : btrfs_lookup_csums_range+0xa4/0xdf0 fs/btrfs/file-item.c:517
sp : ffff800020e76ec0
x29: ffff800020e77000 x28: ffff0000d22fe000 x27: dfff800000000000
x26: dfff800000000000 x25: ffff0000d7b0c210 x24: 0000000000000000
x23: 000000000050d000 x22: 0000000000000001 x21: 0000000000000208
x20: ffff800020e76fc0 x19: 0000000000000001 x18: ffff800011abbcc0
x17: ffff8000181fa000 x16: ffff8000082e7b1c x15: 0000000000000000
x14: ffff00019f6d5e58 x13: 0000000000003000 x12: 0000000000ff0100
x11: ff00800009f2048c x10: 0000000000000000 x9 : ffff800009f2048c
x8 : 0000000000000041 x7 : 00000000003000a8 x6 : 000000000050d000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff0000d7b0c2a8
x2 : 000000000050ffff x1 : 000000000050d000 x0 : 0000000000000000
Call trace:
 btrfs_lookup_csums_range+0xb0/0xdf0 fs/btrfs/file-item.c:518
 scrub_simple_mirror+0x54c/0x1128 fs/btrfs/scrub.c:3481
 scrub_stripe+0x7c8/0x1498 fs/btrfs/scrub.c:3666
 scrub_chunk+0x290/0x364 fs/btrfs/scrub.c:3801
 scrub_enumerate_chunks+0x934/0x1300 fs/btrfs/scrub.c:4070
 btrfs_scrub_dev+0x640/0xedc fs/btrfs/scrub.c:4411
 btrfs_ioctl_scrub+0x1dc/0x3d0 fs/btrfs/ioctl.c:4109
 btrfs_ioctl+0xa1c/0xbd0 fs/btrfs/ioctl.c:5564
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: 979605af f9001ff5 910822b5 d343fea8 (387a6908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	979605af 	bl	0xfffffffffe5816bc
   4:	f9001ff5 	str	x21, [sp, #56]
   8:	910822b5 	add	x21, x21, #0x208
   c:	d343fea8 	lsr	x8, x21, #3
* 10:	387a6908 	ldrb	w8, [x8, x26] <-- trapping instruction