Hi, please backport commit 99c515e3a860 "ext4: fix wrong unit use in ext4_mb_find_by_goal" to the 6.1 stable branch. Commit message """ ext4: fix wrong unit use in ext4_mb_find_by_goal We need start in block unit while fe_start is in cluster unit. Use ext4_grp_offs_to_block helper to convert fe_start to get start in block unit. """ We have seen Syzkaller reports for the 6.1 stable build and this patch fixes the issue. Best regards, Bjoern Report: ======================================================== BTRFS: device fsid a9dcbab4-6f10-4032-8efc-5ec83160ca20 devid 1 transid 11 /dev/loop3 scanned by (udev-worker) (4365) EXT4-fs (loop2): mounted filesystem without journal. Quota mode: writeback. EXT4-fs (loop6): unmounting filesystem. ------------[ cut here ]------------ kernel BUG at fs/ext4/extents.c:3181! invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 1 PID: 11259 Comm: syz.4.281 Not tainted 6.1.100 #6 Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:ext4_split_extent_at+0x854/0xec0 fs/ext4/extents.c:3181 Code: be d3 0c 00 00 48 c7 c7 80 68 1c 87 0f b7 43 08 4c 8d 04 40 49 c1 e0 04 49 01 d8 e8 e6 f5 fe ff e9 2f fe ff ff e8 ac 91 77 ff <0f> 0b e8 a5 91 77 ff 48 8b 74 24 30 44 8b 6c 24 24 48 b8 00 00 00 RSP: 0018:ffffc9000474fb28 EFLAGS: 00010283 RAX: 0000000000006e1a RBX: ffff8880431137ac RCX: ffffc90008a22000 RDX: 0000000000040000 RSI: ffffffff8205dc14 RDI: 0000000000000004 RBP: ffff8880440e6f00 R08: 0000000000000004 R09: 0000000000000000 R10: 0000000000000040 R11: 0000000007c7b872 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000040 FS: 00007f8933cc36c0(0000) GS:ffff88805ab00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2eada31000 CR3: 0000000030544001 CR4: 0000000000770ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: <TASK> ext4_force_split_extent_at fs/ext4/extents.c:338 [inline] ext4_ext_remove_space+0x145d/0x2320 fs/ext4/extents.c:2876 ext4_punch_hole+0x9b1/0x1020 fs/ext4/inode.c:4127 ext4_fallocate+0x6df/0x800 fs/ext4/extents.c:4737 vfs_fallocate+0x46f/0xca0 fs/open.c:323 ksys_fallocate fs/open.c:346 [inline] __do_sys_fallocate fs/open.c:354 [inline] __se_sys_fallocate fs/open.c:352 [inline] __x64_sys_fallocate+0xd6/0x140 fs/open.c:352 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 RIP: 0033:0x7f8932f75d39 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8933cc3048 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 00007f8933103fa0 RCX: 00007f8932f75d39 RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000009 RBP: 00007f8932ff6766 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000010001 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f8933103fa0 R15: 00007fff7b88cd48 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:ext4_split_extent_at+0x854/0xec0 fs/ext4/extents.c:3181 Code: be d3 0c 00 00 48 c7 c7 80 68 1c 87 0f b7 43 08 4c 8d 04 40 49 c1 e0 04 49 01 d8 e8 e6 f5 fe ff e9 2f fe ff ff e8 ac 91 77 ff <0f> 0b e8 a5 91 77 ff 48 8b 74 24 30 44 8b 6c 24 24 48 b8 00 00 00 RSP: 0018:ffffc9000474fb28 EFLAGS: 00010283 RAX: 0000000000006e1a RBX: ffff8880431137ac RCX: ffffc90008a22000 RDX: 0000000000040000 RSI: ffffffff8205dc14 RDI: 0000000000000004 RBP: ffff8880440e6f00 R08: 0000000000000004 R09: 0000000000000000 R10: 0000000000000040 R11: 0000000007c7b872 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000040 FS: 00007f8933cc36c0(0000) GS:ffff88805ab00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2eada31000 CR3: 0000000030544001 CR4: 0000000000770ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400 PKRU: 55555554 Amazon Web Services Development Center Germany GmbH Krausenstr. 38 10117 Berlin Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss Eingetragen am Amtsgericht Charlottenburg unter HRB 257764 B Sitz: Berlin Ust-ID: DE 365 538 597