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: 11712 Comm: syz.0.2065 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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+0x2d04/0x6800 fs/ext4/extents.c:4513
Code: 8b 04 24 89 18 89 9c 24 38 01 00 00 4c 8b 7c 24 10 4d 85 ff 0f 84 bd 00 00 00 e8 77 d5 58 ff 49 8d 7f 08 48 89 f8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 0f 85 3d 1e 00 00 41 0f b7 47 08 c1 e0 04 48
RSP: 0018:ffffc9000c46f800 EFLAGS: 00010246
RAX: 0000000000000000 RBX: fffffffffffffffb RCX: 0000000000080000
RDX: ffffc9000e7f9000 RSI: 0000000000001fda RDI: 0000000000000003
RBP: ffffc9000c46fab0 R08: ffff88802c919e00 R09: 0000000000000002
R10: 00000000ffffffe4 R11: 0000000000000002 R12: 0000000000000001
R13: 1ffff9200188df2c R14: dffffc0000000000 R15: fffffffffffffffb
FS:  00007efd85ddb6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34b1fff8 CR3: 0000000067855000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 ext4_map_blocks+0x9e2/0x1b80 fs/ext4/inode.c:654
 ext4_alloc_file_blocks+0x3df/0xc50 fs/ext4/extents.c:4597
 ext4_fallocate+0xa7f/0x1d40 fs/ext4/extents.c:4890
 vfs_fallocate+0x58e/0x700 fs/open.c:324
 ksys_fallocate fs/open.c:347 [inline]
 __do_sys_fallocate fs/open.c:355 [inline]
 __se_sys_fallocate fs/open.c:353 [inline]
 __x64_sys_fallocate+0xc1/0x110 fs/open.c:353
 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: 0033:0x7efd84f9ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007efd85ddb028 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007efd85216090 RCX: 00007efd84f9ce59
RDX: 0000000000000bf5 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007efd85032d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000002000402 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efd85216128 R14: 00007efd85216090 R15: 00007ffe53ea5918
 </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+0x2d04/0x6800 fs/ext4/extents.c:4513
Code: 8b 04 24 89 18 89 9c 24 38 01 00 00 4c 8b 7c 24 10 4d 85 ff 0f 84 bd 00 00 00 e8 77 d5 58 ff 49 8d 7f 08 48 89 f8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 0f 85 3d 1e 00 00 41 0f b7 47 08 c1 e0 04 48
RSP: 0018:ffffc9000c46f800 EFLAGS: 00010246
RAX: 0000000000000000 RBX: fffffffffffffffb RCX: 0000000000080000
RDX: ffffc9000e7f9000 RSI: 0000000000001fda RDI: 0000000000000003
RBP: ffffc9000c46fab0 R08: ffff88802c919e00 R09: 0000000000000002
R10: 00000000ffffffe4 R11: 0000000000000002 R12: 0000000000000001
R13: 1ffff9200188df2c R14: dffffc0000000000 R15: fffffffffffffffb
FS:  00007efd85ddb6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fba46b93d58 CR3: 0000000067855000 CR4: 00000000003506e0
----------------
Code disassembly (best guess):
   0:	8b 04 24             	mov    (%rsp),%eax
   3:	89 18                	mov    %ebx,(%rax)
   5:	89 9c 24 38 01 00 00 	mov    %ebx,0x138(%rsp)
   c:	4c 8b 7c 24 10       	mov    0x10(%rsp),%r15
  11:	4d 85 ff             	test   %r15,%r15
  14:	0f 84 bd 00 00 00    	je     0xd7
  1a:	e8 77 d5 58 ff       	call   0xff58d596
  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 3d 1e 00 00    	jne    0x1e74
  37:	41 0f b7 47 08       	movzwl 0x8(%r15),%eax
  3c:	c1 e0 04             	shl    $0x4,%eax
  3f:	48                   	rex.W