BUG: unable to handle page fault for address: fffff91ffffff920
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 23ffe5067 P4D 23ffe5067 PUD 1cb13067 PMD 1cb14067 PTE 0
Oops: Oops: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 7859 Comm: syz.2.478 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:rcu_segcblist_restempty kernel/rcu/rcu_segcblist.h:105 [inline]
RIP: 0010:rcu_segcblist_advance+0x7e/0x420 kernel/rcu/rcu_segcblist.c:474
Code: 48 8d 7b 08 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 1a 03 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 63 08 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 0f 85 0d 03 00 00 49 8b 04 24 48 85 c0 0f 84 93 01 00
RSP: 0018:ffffc9001f587748 EFLAGS: 00010012
RAX: dffffc0000000000 RBX: ffffe8ffffc835c0 RCX: dffffc0000000000
RDX: 1ffffd1ffffff920 RSI: fffffffffffffe70 RDI: ffffe8ffffc835c8
RBP: 0000000000000246 R08: 4b21b045db16ba9e R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: ffffe8ffffffc900
R13: ffff888047484388 R14: ffffe8ffffc83540 R15: ffffe8ffffc835c0
FS:  00007f8716a936c0(0000) GS:ffff8881247b3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffff91ffffff920 CR3: 00000000782f1000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 srcu_gp_start_if_needed+0x30f/0xe70 kernel/rcu/srcutree.c:1318
 __call_srcu kernel/rcu/srcutree.c:1391 [inline]
 __synchronize_srcu+0x257/0x290 kernel/rcu/srcutree.c:1443
 bch2_fs_btree_iter_exit+0x451/0x5f0 fs/bcachefs/btree_iter.c:3750
 __bch2_fs_free fs/bcachefs/super.c:617 [inline]
 bch2_fs_release+0x181/0xa10 fs/bcachefs/super.c:667
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1e7/0x5a0 lib/kobject.c:737
 bch2_fs_get_tree+0xd5e/0x1b70 fs/bcachefs/fs.c:2604
 vfs_get_tree+0x8e/0x340 fs/super.c:1815
 do_new_mount fs/namespace.c:3808 [inline]
 path_mount+0x1513/0x2000 fs/namespace.c:4123
 do_mount fs/namespace.c:4136 [inline]
 __do_sys_mount fs/namespace.c:4347 [inline]
 __se_sys_mount fs/namespace.c:4324 [inline]
 __x64_sys_mount+0x28d/0x310 fs/namespace.c:4324
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8715b9066a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8716a92e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f8716a92ef0 RCX: 00007f8715b9066a
RDX: 0000200000000100 RSI: 0000200000000180 RDI: 00007f8716a92eb0
RBP: 0000200000000100 R08: 00007f8716a92ef0 R09: 0000000000200414
R10: 0000000000200414 R11: 0000000000000246 R12: 0000200000000180
R13: 00007f8716a92eb0 R14: 0000000000005ad0 R15: 0000200000001440
 </TASK>
Modules linked in:
CR2: fffff91ffffff920
---[ end trace 0000000000000000 ]---
RIP: 0010:rcu_segcblist_restempty kernel/rcu/rcu_segcblist.h:105 [inline]
RIP: 0010:rcu_segcblist_advance+0x7e/0x420 kernel/rcu/rcu_segcblist.c:474
Code: 48 8d 7b 08 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 1a 03 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 63 08 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 0f 85 0d 03 00 00 49 8b 04 24 48 85 c0 0f 84 93 01 00
RSP: 0018:ffffc9001f587748 EFLAGS: 00010012
RAX: dffffc0000000000 RBX: ffffe8ffffc835c0 RCX: dffffc0000000000
RDX: 1ffffd1ffffff920 RSI: fffffffffffffe70 RDI: ffffe8ffffc835c8
RBP: 0000000000000246 R08: 4b21b045db16ba9e R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: ffffe8ffffffc900
R13: ffff888047484388 R14: ffffe8ffffc83540 R15: ffffe8ffffc835c0
FS:  00007f8716a936c0(0000) GS:ffff8881247b3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffff91ffffff920 CR3: 00000000782f1000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
   0:	48 8d 7b 08          	lea    0x8(%rbx),%rdi
   4:	48 89 fa             	mov    %rdi,%rdx
   7:	48 c1 ea 03          	shr    $0x3,%rdx
   b:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   f:	0f 85 1a 03 00 00    	jne    0x32f
  15:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  1c:	fc ff df
  1f:	4c 8b 63 08          	mov    0x8(%rbx),%r12
  23:	4c 89 e2             	mov    %r12,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2e:	0f 85 0d 03 00 00    	jne    0x341
  34:	49 8b 04 24          	mov    (%r12),%rax
  38:	48 85 c0             	test   %rax,%rax
  3b:	0f                   	.byte 0xf
  3c:	84                   	.byte 0x84
  3d:	93                   	xchg   %eax,%ebx
  3e:	01 00                	add    %eax,(%rax)