BTRFS info (device loop0): clearing free space tree
BTRFS info (device loop0): clearing compat-ro feature flag for FREE_SPACE_TREE (0x1)
BTRFS info (device loop0): clearing compat-ro feature flag for FREE_SPACE_TREE_VALID (0x2)
==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: null-ptr-deref in atomic_inc_not_zero include/linux/atomic/atomic-instrumented.h:577 [inline]
BUG: KASAN: null-ptr-deref in btrfs_root_node+0xf6/0x350 fs/btrfs/ctree.c:140
Write of size 4 at addr 0000000000000060 by task syz.0.17/5083

CPU: 1 PID: 5083 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 __kasan_report mm/kasan/report.c:438 [inline]
 kasan_report+0xd5/0x130 mm/kasan/report.c:451
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x235/0x290 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
 atomic_inc_not_zero include/linux/atomic/atomic-instrumented.h:577 [inline]
 btrfs_root_node+0xf6/0x350 fs/btrfs/ctree.c:140
 btrfs_read_lock_root_node+0x75/0x390 fs/btrfs/locking.c:276
 btrfs_search_slot_get_root fs/btrfs/ctree.c:1654 [inline]
 btrfs_search_slot+0x4b5/0x20a0 fs/btrfs/ctree.c:1818
 btrfs_orphan_cleanup+0x1be/0x940 fs/btrfs/inode.c:3556
 btrfs_cleanup_fs_roots+0x64e/0x990 fs/btrfs/disk-io.c:4305
 btrfs_start_pre_rw_mount+0x18b/0x630 fs/btrfs/disk-io.c:3102
 open_ctree+0x28c0/0x32b0 fs/btrfs/disk-io.c:3634
 btrfs_fill_super+0x1c2/0x2e0 fs/btrfs/super.c:1387
 btrfs_mount_root+0x8c7/0x930 fs/btrfs/super.c:1751
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 fc_mount fs/namespace.c:1005 [inline]
 vfs_kern_mount+0xba/0x150 fs/namespace.c:1035
 btrfs_mount+0x342/0xb10 fs/btrfs/super.c:1811
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x24a/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f5f1912a90a
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5f1878ce58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f5f1878cee0 RCX: 00007f5f1912a90a
RDX: 00002000000051c0 RSI: 0000200000005200 RDI: 00007f5f1878cea0
RBP: 00002000000051c0 R08: 00007f5f1878cee0 R09: 0000000001204408
R10: 0000000001204408 R11: 0000000000000246 R12: 0000200000005200
R13: 00007f5f1878cea0 R14: 00000000000051be R15: 0000200000000180
 </TASK>
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