EXT4-fs error (device loop1): mb_free_blocks:2047: group 0, inode 15: block 305:freeing already freed block (bit 19); block bitmap corrupt. ------------[ cut here ]------------ kernel BUG at fs/ext4/extents.c:2158! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 1 UID: 0 PID: 6100 Comm: syz.1.26 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:ext4_ext_insert_extent+0x4b19/0x4b50 fs/ext4/extents.c:2158 Code: 89 d9 80 e1 07 fe c1 38 c1 0f 8c 98 e7 ff ff 48 89 df e8 1a 57 b0 ff e9 8b e7 ff ff e8 70 74 46 ff 90 0f 0b e8 68 74 46 ff 90 <0f> 0b e8 60 74 46 ff 90 0f 0b 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c RSP: 0018:ffffc9000371ec20 EFLAGS: 00010293 RAX: ffffffff827f2968 RBX: 0000000000000021 RCX: ffff888035e8bc80 RDX: 0000000000000000 RSI: 0000000000000021 RDI: 0000000000000021 RBP: ffffc9000371edd0 R08: ffff8880766ff1d7 R09: 1ffff1100ecdfe3a R10: dffffc0000000000 R11: ffffed100ecdfe3b R12: 0000000000000021 R13: dffffc0000000000 R14: ffff88804322543c R15: ffff88807c3d3200 FS: 00007f39b3a246c0(0000) GS:ffff88812556d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000003000 CR3: 0000000077b4a000 CR4: 00000000003526f0 Call Trace: ext4_ext_map_blocks+0x1696/0x58b0 fs/ext4/extents.c:4459 ext4_map_create_blocks+0x11d/0x540 fs/ext4/inode.c:616 ext4_map_blocks+0x7cd/0x11d0 fs/ext4/inode.c:809 _ext4_get_block+0x1e3/0x470 fs/ext4/inode.c:909 ext4_get_block_unwritten+0x2e/0x100 fs/ext4/inode.c:942 ext4_block_write_begin+0xb14/0x1950 fs/ext4/inode.c:1196 ext4_write_begin+0xb40/0x18c0 fs/ext4/ext4_jbd2.h:-1 ext4_da_write_begin+0x355/0xd80 fs/ext4/inode.c:3123 generic_perform_write+0x2e2/0x8f0 mm/filemap.c:4314 ext4_buffered_write_iter+0xce/0x3a0 fs/ext4/file.c:300 ext4_file_write_iter+0x298/0x1bf0 fs/ext4/file.c:-1 do_iter_readv_writev+0x619/0x8c0 fs/read_write.c:-1 vfs_writev+0x33c/0x990 fs/read_write.c:1059 do_pwritev fs/read_write.c:1155 [inline] __do_sys_pwritev2 fs/read_write.c:1213 [inline] __se_sys_pwritev2+0x184/0x2a0 fs/read_write.c:1204 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f39b2b9aeb9 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:00007f39b3a24028 EFLAGS: 00000246 ORIG_RAX: 0000000000000148 RAX: ffffffffffffffda RBX: 00007f39b2e15fa0 RCX: 00007f39b2b9aeb9 RDX: 0000000000000001 RSI: 0000200000000100 RDI: 0000000000000004 RBP: 00007f39b2c08c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000005412 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f39b2e16038 R14: 00007f39b2e15fa0 R15: 00007ffc7ff48358 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:ext4_ext_insert_extent+0x4b19/0x4b50 fs/ext4/extents.c:2158 Code: 89 d9 80 e1 07 fe c1 38 c1 0f 8c 98 e7 ff ff 48 89 df e8 1a 57 b0 ff e9 8b e7 ff ff e8 70 74 46 ff 90 0f 0b e8 68 74 46 ff 90 <0f> 0b e8 60 74 46 ff 90 0f 0b 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c RSP: 0018:ffffc9000371ec20 EFLAGS: 00010293 RAX: ffffffff827f2968 RBX: 0000000000000021 RCX: ffff888035e8bc80 RDX: 0000000000000000 RSI: 0000000000000021 RDI: 0000000000000021 RBP: ffffc9000371edd0 R08: ffff8880766ff1d7 R09: 1ffff1100ecdfe3a R10: dffffc0000000000 R11: ffffed100ecdfe3b R12: 0000000000000021 R13: dffffc0000000000 R14: ffff88804322543c R15: ffff88807c3d3200 FS: 00007f39b3a246c0(0000) GS:ffff88812556d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fff246ef008 CR3: 0000000077b4a000 CR4: 00000000003526f0