BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 8000000103f82067 P4D 8000000103f82067 PUD 0 
Oops: Oops: 0010 [#1] SMP PTI
CPU: 1 UID: 0 PID: 3355 Comm: syz.2.17 Not tainted 6.15.0-rc4-syzkaller #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc900032e36e8 EFLAGS: 00010206
RAX: 0000000000000000 RBX: ffff888175903d30 RCX: 0000000000000c40
RDX: c9b4080d09c2b886 RSI: 0000000000000000 RDI: 0000000000092800
RBP: 0000000000000c40 R08: 0000000000000000 R09: 00000000000000a5
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000004
R13: 0000000000000010 R14: 0000000000092c40 R15: 0000000000092800
FS:  0000000000000000(0000) GS:ffff8882b32e9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000104fa0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 mempool_alloc_noprof+0x8e/0x1e0 mm/mempool.c:402
 bch2_btree_update_start+0x369/0x830 fs/bcachefs/btree_update_interior.c:1187
 bch2_btree_node_rewrite+0x72/0x510 fs/bcachefs/btree_update_interior.c:2199
 bch2_move_btree+0x402/0x530 fs/bcachefs/move.c:1023
 bch2_scan_old_btree_nodes+0x8d/0x150 fs/bcachefs/move.c:1145
 bch2_data_job+0x16d/0x4e0 fs/bcachefs/move.c:1283
 bch2_data_thread+0x31/0x70 fs/bcachefs/chardev.c:315
 kthread+0x200/0x230 kernel/kthread.c:464
 ret_from_fork+0x32/0x40 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc900032e36e8 EFLAGS: 00010206
RAX: 0000000000000000 RBX: ffff888175903d30 RCX: 0000000000000c40
RDX: c9b4080d09c2b886 RSI: 0000000000000000 RDI: 0000000000092800
RBP: 0000000000000c40 R08: 0000000000000000 R09: 00000000000000a5
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000004
R13: 0000000000000010 R14: 0000000000092c40 R15: 0000000000092800
FS:  0000000000000000(0000) GS:ffff8882b32e9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000104fa0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400