On 8/2/26 12:24 PM, Dongli Zhang wrote:
> vhost_scsi_open() allocates one "struct vhost_scsi_virtqueue" for each
> virtqueue. With large max_io_vqs values, this array can require a
> high-order contiguous allocation and trigger a page allocator warning.
>
> hv# cat /sys/module/vhost_scsi/parameters/max_io_vqs
> 256
>
> [ 766.075787] ------------[ cut here ]------------
> [ 766.077030] WARNING: mm/page_alloc.c:5280 at
> __alloc_frozen_pages_noprof+0x32c/0x15c0, CPU#23: qemu-system-x86/5964
> ... ...
> [ 766.080351] RIP: 0010:__alloc_frozen_pages_noprof+0x32c/0x15c0
> ... ...
> [ 766.085813] Call Trace:
> [ 766.085969] <TASK>
> [ 766.086098] ? srso_alias_return_thunk+0x5/0xfbef5
> [ 766.086365] ? context_struct_compute_av+0x38a/0x4b0
> [ 766.086652] alloc_pages_mpol+0x9f/0x170
> [ 766.086883] ___kmalloc_large_node+0xb6/0xd0
> [ 766.087124] ? srso_alias_return_thunk+0x5/0xfbef5
> [ 766.087389] __kmalloc_large_node_noprof+0x18/0xa0
> [ 766.087655] __kmalloc_noprof+0x3a0/0x440
> [ 766.087877] ? vhost_scsi_open+0xcb/0x2d0 [vhost_scsi]
> [ 766.088162] vhost_scsi_open+0xcb/0x2d0 [vhost_scsi]
> [ 766.088449] misc_open+0x123/0x160
> [ 766.088679] chrdev_open+0xb1/0x230
> [ 766.088885] ? __pfx_chrdev_open+0x10/0x10
> [ 766.089157] do_dentry_open+0x11a/0x470
> [ 766.089389] vfs_open+0x29/0xf0
> [ 766.089596] path_openat+0x7c0/0x1100
> [ 766.089821] do_file_open+0xdd/0x190
> [ 766.090032] ? srso_alias_return_thunk+0x5/0xfbef5
> [ 766.090332] do_sys_openat2+0x7e/0x100
> [ 766.090601] __x64_sys_openat+0x51/0xa0
> [ 766.090857] do_syscall_64+0xfe/0x590
> [ 766.091087] entry_SYSCALL_64_after_hwframe+0x77/0x7f
> [ 766.091411] RIP: 0033:0x7f9525a11fa6
>
> The array does not require physical contiguity, so allocate it with
> kvzalloc_objs() and free it with kvfree().
>
> Signed-off-by: Dongli Zhang <[email protected]>
Reviewed-by: Mike Christie <[email protected]>
