EXT4-fs error (device loop0): ext4_mb_mark_diskspace_used:3861: comm syz.0.54: Allocating blocks 497-513 which overlap fs metadata EXT4-fs error (device loop0): ext4_mb_mark_diskspace_used:3861: comm syz.0.54: Allocating blocks 497-513 which overlap fs metadata BUG: unable to handle page fault for address: ffffffffffffffec #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: 568 Comm: syz.0.54 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:ffffc900014cef00 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000080000 RDX: ffffc90003ad3000 RSI: 00000000000032e8 RDI: ffffffffffffffec RBP: ffffc900014cf1b0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000299d18 R12: dffffc0000000000 R13: 1ffff92000299e0c R14: ffffffffffffffe4 R15: 0000000000000000 FS: 00007fb8f4de46c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffec CR3: 0000000120d2f000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 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] wp_page_shared+0x505/0x8d0 mm/memory.c:3432 do_wp_page+0xde4/0xfc0 mm/memory.c:3584 handle_pte_fault mm/memory.c:5201 [inline] __handle_mm_fault mm/memory.c:5325 [inline] handle_mm_fault+0x1124/0x26c0 mm/memory.c:5465 do_user_addr_fault+0x63b/0x1050 arch/x86/mm/fault.c:1372 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: 0010:copy_user_enhanced_fast_string+0x27/0x40 Code: ca eb 20 0f 01 cb 83 fa 40 72 38 89 d1 f3 a4 31 c0 0f 01 ca c3 89 ca eb 0a 90 90 90 90 90 90 90 90 90 90 83 f8 12 74 0a 89 d1 a4 89 c8 0f 01 ca c3 89 d0 0f 01 ca c3 01 ca eb e7 90 90 90 90 RSP: 0018:ffffc900014cfc08 EFLAGS: 00050287 RAX: 000000000000000e RBX: 0000000000000050 RCX: 0000000000000050 RDX: 0000000000000050 RSI: ffffc900014cfdb0 RDI: 0000200000000980 RBP: ffffc900014cfc30 R08: ffffc900014cfdff R09: 1ffff92000299fbf R10: dffffc0000000000 R11: fffff52000299fc0 R12: 00007fffffffefb0 R13: dffffc0000000000 R14: 0000200000000980 R15: ffffc900014cfdb0 copy_to_user include/linux/uaccess.h:169 [inline] seccomp_notify_recv kernel/seccomp.c:1500 [inline] seccomp_notify_ioctl+0x7a7/0x12d0 kernel/seccomp.c:1715 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0x12f/0x1b0 fs/ioctl.c:856 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856 x64_sys_call+0x58b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17 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: 0033:0x7fb8f3f9cdd9 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:00007fb8f4de4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fb8f4216090 RCX: 00007fb8f3f9cdd9 RDX: 0000200000000980 RSI: 00000000c0502100 RDI: 0000000000000006 RBP: 00007fb8f4032d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb8f4216128 R14: 00007fb8f4216090 R15: 00007ffcc4008118 Modules linked in: CR2: ffffffffffffffec ---[ 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:ffffc900014cef00 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000080000 RDX: ffffc90003ad3000 RSI: 00000000000032e8 RDI: ffffffffffffffec RBP: ffffc900014cf1b0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000299d18 R12: dffffc0000000000 R13: 1ffff92000299e0c R14: ffffffffffffffe4 R15: 0000000000000000 FS: 00007fb8f4de46c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffec CR3: 0000000120d2f000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 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