EXT4-fs error (device loop6): ext4_mb_mark_diskspace_used:3861: comm syz.6.1534: Allocating blocks 497-513 which overlap fs metadata EXT4-fs error (device loop6): ext4_mb_mark_diskspace_used:3861: comm syz.6.1534: Allocating blocks 497-513 which overlap fs metadata BUG: unable to handle page fault for address: ffffffffffffff93 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 7012067 P4D 7012067 PUD 7014067 PMD 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 4990 Comm: syz.6.1534 Not tainted 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+0x2e59/0x6200 fs/ext4/extents.c:4497 Code: 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 8d 04 40 48 89 44 24 08 49 8d 46 28 48 RSP: 0018:ffffc9000157f300 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88810d133cc0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffffffff93 RBP: ffffc9000157f5b0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff520002afd98 R12: dffffc0000000000 R13: 1ffff920002afe8c R14: ffffffffffffff8b R15: 0000000000000000 FS: 000055558f188500(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffff93 CR3: 0000000135745000 CR4: 00000000003526a0 DR0: 0000000000000000 DR1: ffffffffffffffff DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: 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 __block_write_begin_int+0x482/0x1430 fs/buffer.c:2034 __block_write_begin fs/buffer.c:2084 [inline] block_page_mkwrite+0x281/0x300 fs/buffer.c:2558 ext4_page_mkwrite+0x4f8/0x1310 fs/ext4/inode.c:6330 do_page_mkwrite mm/memory.c:3039 [inline] do_shared_fault mm/memory.c:4823 [inline] do_fault+0xdb8/0x1ee0 mm/memory.c:4891 handle_pte_fault mm/memory.c:5183 [inline] __handle_mm_fault mm/memory.c:5325 [inline] handle_mm_fault+0x133a/0x26c0 mm/memory.c:5465 do_user_addr_fault+0x905/0x1050 arch/x86/mm/fault.c:1321 handle_page_fault arch/x86/mm/fault.c:1464 [inline] exc_page_fault+0x51/0xb0 arch/x86/mm/fault.c:1517 asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:608 RIP: 0033:0x7f762e466522 Code: 30 48 8b 14 24 48 85 d2 74 17 8b 44 24 10 0f c8 89 c0 48 89 44 24 10 48 83 fa 01 0f 85 aa 02 00 00 48 8b 44 24 18 8b 74 24 10 <89> 30 e9 1e fe ff ff 48 8b 44 24 18 8b 10 48 8b 04 24 48 85 c0 0f RSP: 002b:00007ffebdf46270 EFLAGS: 00010246 RAX: 0000200000000808 RBX: 0000000000000004 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000021 RDI: 000055558f1883d8 RBP: 00007ffebdf46390 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000021 R11: 0000000000000000 R12: 00007ffebdf463d0 R13: 00007f762e815fac R14: 00000000000316b9 R15: 00007f762e815fa0 Modules linked in: CR2: ffffffffffffff93 ---[ 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+0x2e59/0x6200 fs/ext4/extents.c:4497 Code: 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 8d 04 40 48 89 44 24 08 49 8d 46 28 48 RSP: 0018:ffffc9000157f300 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88810d133cc0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffffffff93 RBP: ffffc9000157f5b0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff520002afd98 R12: dffffc0000000000 R13: 1ffff920002afe8c R14: ffffffffffffff8b R15: 0000000000000000 FS: 000055558f188500(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffff93 CR3: 0000000135745000 CR4: 00000000003526a0 DR0: 0000000000000000 DR1: ffffffffffffffff DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 40 01 00 rex add %eax,(%rax) 3: 00 4d 85 add %cl,-0x7b(%rbp) 6: f6 0f 84 testb $0x84,(%rdi) 9: bc 00 00 00 48 mov $0x48000000,%esp e: 89 5c 24 20 mov %ebx,0x20(%rsp) 12: 49 8d 7e 08 lea 0x8(%r14),%rdi 16: 48 89 f8 mov %rdi,%rax 19: 48 c1 e8 03 shr $0x3,%rax 1d: 42 0f b6 04 20 movzbl (%rax,%r12,1),%eax 22: 84 c0 test %al,%al 24: 0f 85 38 16 00 00 jne 0x1662 * 2a: 41 0f b7 46 08 movzwl 0x8(%r14),%eax <-- trapping instruction 2f: c1 e0 04 shl $0x4,%eax 32: 48 8d 04 40 lea (%rax,%rax,2),%rax 36: 48 89 44 24 08 mov %rax,0x8(%rsp) 3b: 49 8d 46 28 lea 0x28(%r14),%rax 3f: 48 rex.W