loop0: detected capacity change from 0 to 4096
Zero length message leads to an empty skb
BUG: unable to handle page fault for address: ffffed1100024487
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 5ffcd067 P4D 5ffcd067 PUD 0 
Oops: Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 UID: 16895 PID: 5333 Comm: syz.0.0 Not tainted 6.12.0-syzkaller-09073-g9f16d5e6f220 #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:constant_test_bit arch/x86/include/asm/bitops.h:206 [inline]
RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:238 [inline]
RIP: 0010:tif_test_bit include/linux/thread_info.h:192 [inline]
RIP: 0010:tif_need_resched include/linux/thread_info.h:208 [inline]
RIP: 0010:need_resched include/linux/sched.h:2110 [inline]
RIP: 0010:__schedule_loop kernel/sched/core.c:6835 [inline]
RIP: 0010:schedule+0x155/0x320 kernel/sched/core.c:6848
Code: c1 eb 03 eb 0a 48 f7 45 00 08 00 00 00 74 2c bf 01 00 00 00 e8 9c 5c 94 f5 31 ff e8 75 b2 ff ff bf 01 00 00 00 e8 2b 5e 94 f5 <42> 80 3c 23 00 74 d4 48 89 ef e8 7c 31 31 f6 eb ca 4c 8d 75 2c 4d
RSP: 0018:ffffc9000d507130 EFLAGS: 00010297
RAX: 0000000080000001 RBX: 1ffff11000024488 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000001
RBP: ffff888000122440 R08: ffff88801211b0c3 R09: 1ffff11002423618
R10: dffffc0000000000 R11: ffffed1002423619 R12: dffffc00ffffffff
R13: 0000000000000000 R14: ffffffff8bcf8fe0 R15: ffff8880001236b8
FS:  00007fc95a4336c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffed1100024487 CR3: 0000000040580000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 io_schedule+0x8d/0x110 kernel/sched/core.c:7681
 folio_wait_bit_common+0x882/0x12b0 mm/filemap.c:1308
 __filemap_get_folio+0xaf/0xbd0 mm/filemap.c:1899
 filemap_lock_folio include/linux/pagemap.h:788 [inline]
 collapse_file mm/khugepaged.c:1910 [inline]
 hpage_collapse_scan_file+0x1d07/0x6880 mm/khugepaged.c:2332
 madvise_collapse+0x602/0xd30 mm/khugepaged.c:2774
 madvise_vma_behavior mm/madvise.c:1316 [inline]
 madvise_walk_vmas mm/madvise.c:1497 [inline]
 do_madvise+0x1833/0x4d10 mm/madvise.c:1684
 __do_sys_madvise mm/madvise.c:1700 [inline]
 __se_sys_madvise mm/madvise.c:1698 [inline]
 __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:1698
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc95957e819
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007fc95a433038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007fc959735fa0 RCX: 00007fc95957e819
RDX: 0000000000000019 RSI: 0000000000800000 RDI: 00000000207fe000
RBP: 00007fc9595f175e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fc959735fa0 R15: 00007ffc55a7d128
 </TASK>
Modules linked in:
CR2: ffffed1100024487
---[ end trace 0000000000000000 ]---
RIP: 0010:constant_test_bit arch/x86/include/asm/bitops.h:206 [inline]
RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:238 [inline]
RIP: 0010:tif_test_bit include/linux/thread_info.h:192 [inline]
RIP: 0010:tif_need_resched include/linux/thread_info.h:208 [inline]
RIP: 0010:need_resched include/linux/sched.h:2110 [inline]
RIP: 0010:__schedule_loop kernel/sched/core.c:6835 [inline]
RIP: 0010:schedule+0x155/0x320 kernel/sched/core.c:6848
Code: c1 eb 03 eb 0a 48 f7 45 00 08 00 00 00 74 2c bf 01 00 00 00 e8 9c 5c 94 f5 31 ff e8 75 b2 ff ff bf 01 00 00 00 e8 2b 5e 94 f5 <42> 80 3c 23 00 74 d4 48 89 ef e8 7c 31 31 f6 eb ca 4c 8d 75 2c 4d
RSP: 0018:ffffc9000d507130 EFLAGS: 00010297
RAX: 0000000080000001 RBX: 1ffff11000024488 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000001
RBP: ffff888000122440 R08: ffff88801211b0c3 R09: 1ffff11002423618
R10: dffffc0000000000 R11: ffffed1002423619 R12: dffffc00ffffffff
R13: 0000000000000000 R14: ffffffff8bcf8fe0 R15: ffff8880001236b8
FS:  00007fc95a4336c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffed1100024487 CR3: 0000000040580000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	c1 eb 03             	shr    $0x3,%ebx
   3:	eb 0a                	jmp    0xf
   5:	48 f7 45 00 08 00 00 	testq  $0x8,0x0(%rbp)
   c:	00
   d:	74 2c                	je     0x3b
   f:	bf 01 00 00 00       	mov    $0x1,%edi
  14:	e8 9c 5c 94 f5       	call   0xf5945cb5
  19:	31 ff                	xor    %edi,%edi
  1b:	e8 75 b2 ff ff       	call   0xffffb295
  20:	bf 01 00 00 00       	mov    $0x1,%edi
  25:	e8 2b 5e 94 f5       	call   0xf5945e55
* 2a:	42 80 3c 23 00       	cmpb   $0x0,(%rbx,%r12,1) <-- trapping instruction
  2f:	74 d4                	je     0x5
  31:	48 89 ef             	mov    %rbp,%rdi
  34:	e8 7c 31 31 f6       	call   0xf63131b5
  39:	eb ca                	jmp    0x5
  3b:	4c 8d 75 2c          	lea    0x2c(%rbp),%r14
  3f:	4d                   	rex.WRB