On Fri, Aug 21, 2026 at 11:37:36AM -0700, Long Li wrote:
> mana_gd_query_max_resources() sizes gc->num_msix_usable from resp.max_msix
> and the CPU count, but never from the device MSI-X table. On a 1792 vCPU
> M-series VM that yields 1793 while the table has 1024 entries, and
> mana_gd_setup_remaining_irqs() then walks indices 1..1792, running off the
> end of the region mapped by msix_map_region():
>
> BUG: unable to handle page fault for address: ff8e347f8b99800c
> RIP: 0010:msix_prepare_msi_desc+0x7a/0x90
> RAX: 0000000000004000 RBX: ff4330cb164ea780 RCX: ff8e347f8b998000
> Call Trace:
> <TASK>
> __msi_domain_alloc_irqs+0x13a/0x440
> msi_domain_alloc_irq_at+0x149/0x1b0
> mana_gd_setup+0x351/0x890
> mana_gd_probe+0x274/0x390
> </TASK>
>
> RAX is index 1024 * PCI_MSIX_ENTRY_SIZE, one entry past the table.
>
> msi_insert_desc() does range check the index, but only against the MSI
> domain hwsize, which matches the table only for devices on an MSI parent
> domain. With a global PCI/MSI domain hwsize is MSI_XA_DOMAIN_SIZE, so
> nothing bounds the request.
>
> Cap num_msix_usable with pci_msix_vec_count().
>
> Fixes: 755391121038 ("net: mana: Allocate MSI-X vectors dynamically")
> Signed-off-by: Long Li <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
