EXT4-fs error (device loop8): ext4_do_update_inode:5255: inode #2: comm syz.8.6699: corrupted inode contents
EXT4-fs (loop8): Remounting filesystem read-only
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 28066 Comm: syz.8.6699 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/13/2026
RIP: 0010:ext4_ext_drop_refs fs/ext4/extents.c:119 [inline]
RIP: 0010:ext4_free_ext_path fs/ext4/extents.c:128 [inline]
RIP: 0010:ext4_ext_map_blocks+0x2d14/0x6890 fs/ext4/extents.c:4513
Code: 44 24 08 89 18 89 9c 24 38 01 00 00 4c 8b 7c 24 18 4d 85 ff 0f 84 b1 e2 ff ff e8 47 b5 58 ff 49 8d 7f 08 48 89 f8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 0f 85 e7 1d 00 00 41 0f b7 47 08 c1 e0 04 48
RSP: 0018:ffffc9000c737500 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000015 RCX: 0000000000080000
RDX: ffffc9000d64b000 RSI: 0000000000033b57 RDI: 0000000000000003
RBP: ffffc9000c7377b0 R08: ffff8880322d3c00 R09: 0000000000000002
R10: 00000000ffffffe4 R11: 0000000000000002 R12: 0000000000000001
R13: 1ffff920018e6ecc R14: dffffc0000000000 R15: fffffffffffffffb
FS:  00007fbbd3ff66c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f71b7dfdeec CR3: 000000002bb6f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 00000000000f010e DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ext4_map_blocks+0x9db/0x1a90 fs/ext4/inode.c:654
 ext4_getblk+0x1c9/0x720 fs/ext4/inode.c:864
 ext4_bread+0x2a/0x170 fs/ext4/inode.c:920
 ext4_append+0x2bf/0x560 fs/ext4/namei.c:83
 ext4_add_entry+0x9eb/0xd90 fs/ext4/namei.c:2511
 ext4_mkdir+0x524/0xc90 fs/ext4/namei.c:3081
 vfs_mkdir+0x2a5/0x470 fs/namei.c:4121
 do_mkdirat+0x1dc/0x450 fs/namei.c:4144
 __do_sys_mkdirat fs/namei.c:4159 [inline]
 __se_sys_mkdirat fs/namei.c:4157 [inline]
 __x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4157
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fbbd5d9cd07
Code: 00 66 90 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 db f7 ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 b8 02 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbbd3ff5e58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007fbbd3ff5ee0 RCX: 00007fbbd5d9cd07
RDX: 00000000000001ff RSI: 0000200000000000 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000000
R13: 00007fbbd3ff5ea0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_ext_drop_refs fs/ext4/extents.c:119 [inline]
RIP: 0010:ext4_free_ext_path fs/ext4/extents.c:128 [inline]
RIP: 0010:ext4_ext_map_blocks+0x2d14/0x6890 fs/ext4/extents.c:4513
Code: 44 24 08 89 18 89 9c 24 38 01 00 00 4c 8b 7c 24 18 4d 85 ff 0f 84 b1 e2 ff ff e8 47 b5 58 ff 49 8d 7f 08 48 89 f8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 0f 85 e7 1d 00 00 41 0f b7 47 08 c1 e0 04 48
RSP: 0018:ffffc9000c737500 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000015 RCX: 0000000000080000
RDX: ffffc9000d64b000 RSI: 0000000000033b57 RDI: 0000000000000003
RBP: ffffc9000c7377b0 R08: ffff8880322d3c00 R09: 0000000000000002
R10: 00000000ffffffe4 R11: 0000000000000002 R12: 0000000000000001
R13: 1ffff920018e6ecc R14: dffffc0000000000 R15: fffffffffffffffb
FS:  00007fbbd3ff66c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff0858d6ff8 CR3: 000000002bb6f000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 00000000000f010e DR6: 00000000ffff0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	44 24 08             	rex.R and $0x8,%al
   3:	89 18                	mov    %ebx,(%rax)
   5:	89 9c 24 38 01 00 00 	mov    %ebx,0x138(%rsp)
   c:	4c 8b 7c 24 18       	mov    0x18(%rsp),%r15
  11:	4d 85 ff             	test   %r15,%r15
  14:	0f 84 b1 e2 ff ff    	je     0xffffe2cb
  1a:	e8 47 b5 58 ff       	call   0xff58b566
  1f:	49 8d 7f 08          	lea    0x8(%r15),%rdi
  23:	48 89 f8             	mov    %rdi,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 30       	movzbl (%rax,%r14,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 e7 1d 00 00    	jne    0x1e1e
  37:	41 0f b7 47 08       	movzwl 0x8(%r15),%eax
  3c:	c1 e0 04             	shl    $0x4,%eax
  3f:	48                   	rex.W