BUG: unable to handle page fault for address: ffffe8fffd451040
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 1b03f067 P4D 1b03f067 PUD 1ed11067 PMD 49f70067 PTE 0
Oops: Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 75 Comm: kswapd0 Not tainted 6.14.0-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:__btree_node_reclaim+0x647/0xa00 fs/bcachefs/btree_cache.c:444
Code: 00 49 8d 9f 48 b6 04 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 1c 0d e1 fd 48 8b 03 <65> 48 ff 40 40 0f 1f 44 00 00 e8 7a cd 79 fd 65 8b 1d 2f c4 bb 7b
RSP: 0018:ffffc9000106f270 EFLAGS: 00010246
RAX: 0000607fdd851000 RBX: ffff88804904b648 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 1db8f60c84bb244c RDI: 0000000000000000
RBP: 1db8f60c84bb244c R08: ffffffff84481215 R09: 1ffff11009433016
R10: dffffc0000000000 R11: ffffed1009433017 R12: ffff88804a198000
R13: ffffffff84480d4c R14: 1ffff11009433016 R15: ffff888049000000
FS:  0000000000000000(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffe8fffd451040 CR3: 0000000040926000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 btree_node_reclaim fs/bcachefs/btree_cache.c:456 [inline]
 bch2_btree_cache_scan+0x63e/0xec0 fs/bcachefs/btree_cache.c:525
 do_shrink_slab+0x72d/0x1160 mm/shrinker.c:437
 shrink_slab+0x1093/0x14d0 mm/shrinker.c:664
 shrink_one+0x43b/0x850 mm/vmscan.c:4868
 shrink_many mm/vmscan.c:4929 [inline]
 lru_gen_shrink_node mm/vmscan.c:5007 [inline]
 shrink_node+0x379b/0x3e20 mm/vmscan.c:5978
 kswapd_shrink_node mm/vmscan.c:6807 [inline]
 balance_pgdat mm/vmscan.c:6999 [inline]
 kswapd+0x20f3/0x3b10 mm/vmscan.c:7264
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Modules linked in:
CR2: ffffe8fffd451040
---[ end trace 0000000000000000 ]---
RIP: 0010:__btree_node_reclaim+0x647/0xa00 fs/bcachefs/btree_cache.c:444
Code: 00 49 8d 9f 48 b6 04 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 1c 0d e1 fd 48 8b 03 <65> 48 ff 40 40 0f 1f 44 00 00 e8 7a cd 79 fd 65 8b 1d 2f c4 bb 7b
RSP: 0018:ffffc9000106f270 EFLAGS: 00010246
RAX: 0000607fdd851000 RBX: ffff88804904b648 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 1db8f60c84bb244c RDI: 0000000000000000
RBP: 1db8f60c84bb244c R08: ffffffff84481215 R09: 1ffff11009433016
R10: dffffc0000000000 R11: ffffed1009433017 R12: ffff88804a198000
R13: ffffffff84480d4c R14: 1ffff11009433016 R15: ffff888049000000
FS:  0000000000000000(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffe8fffd451040 CR3: 0000000040926000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	49 8d 9f 48 b6 04 00 	lea    0x4b648(%r15),%rbx
   7:	48 89 d8             	mov    %rbx,%rax
   a:	48 c1 e8 03          	shr    $0x3,%rax
   e:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  15:	fc ff df
  18:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1)
  1c:	74 08                	je     0x26
  1e:	48 89 df             	mov    %rbx,%rdi
  21:	e8 1c 0d e1 fd       	call   0xfde10d42
  26:	48 8b 03             	mov    (%rbx),%rax
* 29:	65 48 ff 40 40       	incq   %gs:0x40(%rax) <-- trapping instruction
  2e:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  33:	e8 7a cd 79 fd       	call   0xfd79cdb2
  38:	65 8b 1d 2f c4 bb 7b 	mov    %gs:0x7bbbc42f(%rip),%ebx        # 0x7bbbc46e