BUG: unable to handle kernel NULL pointer dereference in mempool_alloc

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	BUG: unable to handle kernel NULL pointer dereference in mempool_alloc_noprof block				3	304d	334d	0/28	auto-obsoleted due to no activity on 2024/09/23 15:37
bcachefs (loop0): compression opt none set but not marked in superblock, fixing
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 0 P4D 0 
Oops: Oops: 0010 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5341 Comm: bch-rebalance/l Not tainted 6.15.0-rc2-syzkaller-00488-g6fea5fabd332 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc9000d70ebd8 EFLAGS: 00010246
RAX: 1ffff1100a6c8e84 RBX: ffff888053647420 RCX: ffff888053647420
RDX: ffff8880007cc880 RSI: 0000000000000000 RDI: 0000000000092800
RBP: ffffc9000d70ed30 R08: ffffffff81fe7502 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000092800 R14: dffffc0000000000 R15: 0000000000092c40
FS:  0000000000000000(0000) GS:ffff88808c59a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000044068000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 mempool_alloc_noprof+0x199/0x5a0 mm/mempool.c:402
 __bio_compress fs/bcachefs/compress.c:461 [inline]
 bch2_bio_compress+0x3ca/0x15c0 fs/bcachefs/compress.c:555
 bch2_write_extent fs/bcachefs/io_write.c:1020 [inline]
 __bch2_write+0x117c/0x46c0 fs/bcachefs/io_write.c:1515
 bch2_write+0x834/0x15d0 fs/bcachefs/io_write.c:1681
 move_write fs/bcachefs/move.c:160 [inline]
 bch2_moving_ctxt_do_pending_writes+0x589/0xa70 fs/bcachefs/move.c:191
 bch2_moving_ctxt_flush_all+0x269/0x3a0 fs/bcachefs/move.c:206
 do_rebalance fs/bcachefs/rebalance.c:566 [inline]
 bch2_rebalance_thread+0x1a42/0x1fa0 fs/bcachefs/rebalance.c:588
 kthread+0x7b7/0x940 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 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:ffffc9000d70ebd8 EFLAGS: 00010246
RAX: 1ffff1100a6c8e84 RBX: ffff888053647420 RCX: ffff888053647420
RDX: ffff8880007cc880 RSI: 0000000000000000 RDI: 0000000000092800
RBP: ffffc9000d70ed30 R08: ffffffff81fe7502 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000092800 R14: dffffc0000000000 R15: 0000000000092c40
FS:  0000000000000000(0000) GS:ffff88808c59a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000044068000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400