BUG: unable to handle kernel paging request in bch2_btree_cache

Kernel	Title	Rank 🛈	Count	Last	Reported	Patched	Status
upstream	BUG: unable to handle kernel paging request in bch2_btree_cache_scan (3) bcachefs	8	14	215d	252d	0/29	auto-obsoleted due to no activity on 2025/06/01 22:28
upstream	BUG: unable to handle kernel paging request in bch2_btree_cache_scan (2) bcachefs	8	12	338d	347d	0/29	auto-obsoleted due to no activity on 2025/01/29 11:18
upstream	BUG: unable to handle kernel paging request in bch2_btree_cache_scan bcachefs	8	2	512d	514d	0/29	auto-obsoleted due to no activity on 2024/08/29 02:52

BTRFS info (device loop3): enabling free space tree
BTRFS info (device loop3): enabling auto defrag
Unable to handle kernel paging request at virtual address fffffdffbf6f10c0
KASAN: maybe wild-memory-access in range [0x0003effdfb788600-0x0003effdfb788607]
Mem abort info:
  ESR = 0x0000000096000007
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x07: level 3 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000007, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000206b5f000
[fffffdffbf6f10c0] pgd=0000000000000000, p4d=100000023ea69403, pud=10000001031ad403, pmd=10000001031ae403, pte=0000000000000000
Internal error: Oops: 0000000096000007 [#1]  SMP
Modules linked in:
CPU: 0 UID: 0 PID: 7608 Comm: syz.3.168 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 63400005 (nZCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : __percpu_add_case_64 arch/arm64/include/asm/percpu.h:127 [inline]
pc : bch2_btree_cache_scan+0x9f4/0xdc4 fs/bcachefs/btree_cache.c:560
lr : bch2_btree_cache_scan+0x984/0xdc4 fs/bcachefs/btree_cache.c:556
sp : ffff8000a52673c0
x29: ffff8000a5267470 x28: dfff800000000000 x27: 1ffff00014a4ced9
x26: ffff8000a52676c8 x25: 0000000000000000 x24: 1fffe0001a06db71
x23: ffff0000d036db80 x22: ffff0000f7b01ce8 x21: ffff0000f7b4b5c0
x20: ffff0000d036db88 x19: 00000000fffbffff x18: 1fffe00033771c88
x17: ffff80008f85e000 x16: ffff80008b065ce0 x15: 0000000000000001
x14: 1ffff00014a4ce60 x13: 0000000000000000 x12: 0000000000000000
x11: ffff700014a4ce61 x10: dfff800000000000 x9 : 0000000000000001
x8 : fffffdffbf6f10c0 x7 : ffff80008283cbc8 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff80008b075be8
x2 : 0000000000000001 x1 : 0000000000000008 x0 : 0000000000000001
Call trace:
 bch2_btree_cache_scan+0x9f4/0xdc4 fs/bcachefs/btree_cache.c:560 (P)
 do_shrink_slab+0x650/0x11b0 mm/shrinker.c:437
 shrink_slab+0xc68/0xfb8 mm/shrinker.c:664
 drop_slab_node mm/vmscan.c:441 [inline]
 drop_slab+0x120/0x248 mm/vmscan.c:459
 drop_caches_sysctl_handler+0x170/0x300 fs/drop_caches.c:68
 proc_sys_call_handler+0x460/0x7e8 fs/proc/proc_sysctl.c:600
 proc_sys_write+0x2c/0x3c fs/proc/proc_sysctl.c:626
 do_iter_readv_writev+0x4c0/0x724 fs/read_write.c:-1
 vfs_writev+0x29c/0x7cc fs/read_write.c:1057
 do_writev+0x128/0x290 fs/read_write.c:1103
 __do_sys_writev fs/read_write.c:1171 [inline]
 __se_sys_writev fs/read_write.c:1168 [inline]
 __arm64_sys_writev+0x80/0x94 fs/read_write.c:1168
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
Code: d538d089 8b090108 52800029 91030108 (f829011f) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	d538d089 	mrs	x9, tpidr_el1
   4:	8b090108 	add	x8, x8, x9
   8:	52800029 	mov	w9, #0x1                   	// #1
   c:	91030108 	add	x8, x8, #0xc0
* 10:	f829011f 	stadd	x9, [x8] <-- trapping instruction