loop0: detected capacity change from 0 to 1024
EXT4-fs (loop0): mounted filesystem without journal. Quota mode: none.
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 3232 Comm: syz.0.802 Tainted: G        W          syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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+0x2e4c/0x6200 fs/ext4/extents.c:4497
Code: 1a 00 00 48 8b 04 24 89 18 4c 8b b4 24 40 01 00 00 4d 85 f6 0f 84 bc 00 00 00 48 89 5c 24 20 49 8d 7e 08 48 89 f8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 38 16 00 00 41 0f b7 46 08 c1 e0 04 48
RSP: 0000:ffffc900074c6fc0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000080000
RDX: ffffc90000e09000 RSI: 0000000000003aa6 RDI: 0000000000000003
RBP: ffffc900074c7270 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000e98d30 R12: dffffc0000000000
R13: 1ffff92000e98e24 R14: fffffffffffffffb R15: 0000000000000000
FS:  00007f33d81406c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2bb00bb000 CR3: 000000010d730000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ext4_map_blocks+0x9d8/0x1b70 fs/ext4/inode.c:679
 _ext4_get_block+0x1ea/0x540 fs/ext4/inode.c:822
 ext4_get_block+0x39/0x50 fs/ext4/inode.c:839
 ext4_block_write_begin+0x594/0x1280 fs/ext4/inode.c:1124
 ext4_write_begin+0x600/0xf90 fs/ext4/ext4_jbd2.h:-1
 ext4_da_write_begin+0x3e7/0x8c0 fs/ext4/inode.c:3001
 generic_perform_write+0x32d/0x740 mm/filemap.c:3914
 ext4_buffered_write_iter+0x367/0x630 fs/ext4/file.c:285
 ext4_file_write_iter+0x191/0x1500 fs/ext4/file.c:-1
 call_write_iter include/linux/fs.h:2282 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x603/0xce0 fs/read_write.c:584
 ksys_pwrite64 fs/read_write.c:699 [inline]
 __do_sys_pwrite64 fs/read_write.c:709 [inline]
 __se_sys_pwrite64 fs/read_write.c:706 [inline]
 __x64_sys_pwrite64+0x197/0x220 fs/read_write.c:706
 x64_sys_call+0x36/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:19
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f33d719ce59
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:00007f33d8140028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f33d7415fa0 RCX: 00007f33d719ce59
RDX: 000000000000ff10 RSI: 0000200000000140 RDI: 0000000000000007
RBP: 00007f33d7232d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000008000c61 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f33d7416038 R14: 00007f33d7415fa0 R15: 00007fff08286e18
 </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+0x2e4c/0x6200 fs/ext4/extents.c:4497
Code: 1a 00 00 48 8b 04 24 89 18 4c 8b b4 24 40 01 00 00 4d 85 f6 0f 84 bc 00 00 00 48 89 5c 24 20 49 8d 7e 08 48 89 f8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 38 16 00 00 41 0f b7 46 08 c1 e0 04 48
RSP: 0000:ffffc900074c6fc0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000080000
RDX: ffffc90000e09000 RSI: 0000000000003aa6 RDI: 0000000000000003
RBP: ffffc900074c7270 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000e98d30 R12: dffffc0000000000
R13: 1ffff92000e98e24 R14: fffffffffffffffb R15: 0000000000000000
FS:  00007f33d81406c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7ee077b000 CR3: 000000010d730000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	1a 00                	sbb    (%rax),%al
   2:	00 48 8b             	add    %cl,-0x75(%rax)
   5:	04 24                	add    $0x24,%al
   7:	89 18                	mov    %ebx,(%rax)
   9:	4c 8b b4 24 40 01 00 	mov    0x140(%rsp),%r14
  10:	00
  11:	4d 85 f6             	test   %r14,%r14
  14:	0f 84 bc 00 00 00    	je     0xd6
  1a:	48 89 5c 24 20       	mov    %rbx,0x20(%rsp)
  1f:	49 8d 7e 08          	lea    0x8(%r14),%rdi
  23:	48 89 f8             	mov    %rdi,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 20       	movzbl (%rax,%r12,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 38 16 00 00    	jne    0x166f
  37:	41 0f b7 46 08       	movzwl 0x8(%r14),%eax
  3c:	c1 e0 04             	shl    $0x4,%eax
  3f:	48                   	rex.W