Re: [PATCH] ext4: fix hole length calculation overflow in non-extent inodes

[Theodore Ts'o]

On Mon, 11 Aug 2025 14:45:32 +0800, Zhang Yi wrote:
> In a filesystem with a block size larger than 4KB, the hole length
> calculation for a non-extent inode in ext4_ind_map_blocks() can easily
> exceed INT_MAX. Then it could return a zero length hole and trigger the
> following waring and infinite in the iomap infrastructure.
> 
>   ------------[ cut here ]------------
>   WARNING: CPU: 3 PID: 434101 at fs/iomap/iter.c:34 iomap_iter_done+0x148/0x190
>   CPU: 3 UID: 0 PID: 434101 Comm: fsstress Not tainted 6.16.0-rc7+ #128 PREEMPT(voluntary)
>   Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022
>   pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>   pc : iomap_iter_done+0x148/0x190
>   lr : iomap_iter+0x174/0x230
>   sp : ffff8000880af740
>   x29: ffff8000880af740 x28: ffff0000db8e6840 x27: 0000000000000000
>   x26: 0000000000000000 x25: ffff8000880af830 x24: 0000004000000000
>   x23: 0000000000000002 x22: 000001bfdbfa8000 x21: ffffa6a41c002e48
>   x20: 0000000000000001 x19: ffff8000880af808 x18: 0000000000000000
>   x17: 0000000000000000 x16: ffffa6a495ee6cd0 x15: 0000000000000000
>   x14: 00000000000003d4 x13: 00000000fa83b2da x12: 0000b236fc95f18c
>   x11: ffffa6a4978b9c08 x10: 0000000000001da0 x9 : ffffa6a41c1a2a44
>   x8 : ffff8000880af5c8 x7 : 0000000001000000 x6 : 0000000000000000
>   x5 : 0000000000000004 x4 : 000001bfdbfa8000 x3 : 0000000000000000
>   x2 : 0000000000000000 x1 : 0000004004030000 x0 : 0000000000000000
>   Call trace:
>    iomap_iter_done+0x148/0x190 (P)
>    iomap_iter+0x174/0x230
>    iomap_fiemap+0x154/0x1d8
>    ext4_fiemap+0x110/0x140 [ext4]
>    do_vfs_ioctl+0x4b8/0xbc0
>    __arm64_sys_ioctl+0x8c/0x120
>    invoke_syscall+0x6c/0x100
>    el0_svc_common.constprop.0+0x48/0xf0
>    do_el0_svc+0x24/0x38
>    el0_svc+0x38/0x120
>    el0t_64_sync_handler+0x10c/0x138
>    el0t_64_sync+0x198/0x1a0
>   ---[ end trace 0000000000000000 ]---
> 
> [...]

Applied, thanks!

[1/1] ext4: fix hole length calculation overflow in non-extent inodes
      commit: 02c7f7219ac0e2277b3379a3a0e9841ef464b6d4

Best regards,
-- 
Theodore Ts'o <tytso@xxxxxxx>