BTRFS info (device loop0): using free space tree
BTRFS error (device loop0): failed to load root extent
BTRFS info (device loop0): enabling ssd optimizations
general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 PID: 5931 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:btrfs_root_node+0x7f/0x3a0 fs/btrfs/ctree.c:260
Code: e7 7c f7 fd 48 83 c4 08 e8 2e 01 f8 06 89 c5 31 ff 89 c6 e8 43 18 16 fe 85 ed 74 17 e8 8a 1d 00 fe 84 c0 74 1c e8 81 14 16 fe <42> 80 3c 2b 00 75 4b eb 51 e8 73 14 16 fe 42 80 3c 2b 00 75 3d eb
RSP: 0018:ffffc900032b7598 EFLAGS: 00010293
RAX: ffffffff836f7c3f RBX: 0000000000000003 RCX: ffff88802bf9bc00
RDX: 0000000000000000 RSI: ffffffff8afc6f60 RDI: ffffffff8afc6f20
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff21b28a0
R10: dffffc0000000000 R11: fffffbfff21b28a1 R12: ffffffff836f7bfc
R13: dffffc0000000000 R14: 0000000000000018 R15: 0000000000000038
FS:  0000555582ab6500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5302a5b000 CR3: 000000002f1ca000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 btrfs_read_lock_root_node+0x82/0x3a0 fs/btrfs/locking.c:278
 btrfs_build_ref_tree+0x11e/0x1200 fs/btrfs/ref-verify.c:1005
 open_ctree+0x22cc/0x2ce0 fs/btrfs/disk-io.c:3539
 btrfs_fill_super+0x1c2/0x300 fs/btrfs/super.c:1163
 btrfs_mount_root+0x8be/0x920 fs/btrfs/super.c:1527
 legacy_get_tree+0xea/0x180 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x280 fs/super.c:1764
 fc_mount fs/namespace.c:1117 [inline]
 vfs_kern_mount+0xbe/0x160 fs/namespace.c:1147
 btrfs_mount+0x2e1/0xa70 fs/btrfs/super.c:1587
 legacy_get_tree+0xea/0x180 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x280 fs/super.c:1764
 do_new_mount+0x24b/0xa40 fs/namespace.c:3386
 do_mount fs/namespace.c:3726 [inline]
 __do_sys_mount fs/namespace.c:3935 [inline]
 __se_sys_mount+0x2da/0x3c0 fs/namespace.c:3912
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4a58990eea
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007ffce34919c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffce3491a50 RCX: 00007f4a58990eea
RDX: 0000200000000000 RSI: 0000200000000040 RDI: 00007ffce3491a10
RBP: 0000200000000000 R08: 00007ffce3491a50 R09: 000000000001c005
R10: 000000000001c005 R11: 0000000000000246 R12: 0000200000000040
R13: 00007ffce3491a10 R14: 00000000000055ae R15: 00002000000003c0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:btrfs_root_node+0x7f/0x3a0 fs/btrfs/ctree.c:260
Code: e7 7c f7 fd 48 83 c4 08 e8 2e 01 f8 06 89 c5 31 ff 89 c6 e8 43 18 16 fe 85 ed 74 17 e8 8a 1d 00 fe 84 c0 74 1c e8 81 14 16 fe <42> 80 3c 2b 00 75 4b eb 51 e8 73 14 16 fe 42 80 3c 2b 00 75 3d eb
RSP: 0018:ffffc900032b7598 EFLAGS: 00010293
RAX: ffffffff836f7c3f RBX: 0000000000000003 RCX: ffff88802bf9bc00
RDX: 0000000000000000 RSI: ffffffff8afc6f60 RDI: ffffffff8afc6f20
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff21b28a0
R10: dffffc0000000000 R11: fffffbfff21b28a1 R12: ffffffff836f7bfc
R13: dffffc0000000000 R14: 0000000000000018 R15: 0000000000000038
FS:  0000555582ab6500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5302a5b000 CR3: 000000002f1ca000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
   0:	e7 7c                	out    %eax,$0x7c
   2:	f7 fd                	idiv   %ebp
   4:	48 83 c4 08          	add    $0x8,%rsp
   8:	e8 2e 01 f8 06       	call   0x6f8013b
   d:	89 c5                	mov    %eax,%ebp
   f:	31 ff                	xor    %edi,%edi
  11:	89 c6                	mov    %eax,%esi
  13:	e8 43 18 16 fe       	call   0xfe16185b
  18:	85 ed                	test   %ebp,%ebp
  1a:	74 17                	je     0x33
  1c:	e8 8a 1d 00 fe       	call   0xfe001dab
  21:	84 c0                	test   %al,%al
  23:	74 1c                	je     0x41
  25:	e8 81 14 16 fe       	call   0xfe1614ab
* 2a:	42 80 3c 2b 00       	cmpb   $0x0,(%rbx,%r13,1) <-- trapping instruction
  2f:	75 4b                	jne    0x7c
  31:	eb 51                	jmp    0x84
  33:	e8 73 14 16 fe       	call   0xfe1614ab
  38:	42 80 3c 2b 00       	cmpb   $0x0,(%rbx,%r13,1)
  3d:	75 3d                	jne    0x7c
  3f:	eb                   	.byte 0xeb