From: Simon Horman <horms@kernel.org>
To: Long Li <longli@microsoft.com>
Cc: Konstantin Taranov <kotaranov@microsoft.com>,
Jakub Kicinski <kuba@kernel.org>,
"David S . Miller" <davem@davemloft.net>,
Paolo Abeni <pabeni@redhat.com>,
Eric Dumazet <edumazet@google.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
Jason Gunthorpe <jgg@ziepe.ca>, Leon Romanovsky <leon@kernel.org>,
Haiyang Zhang <haiyangz@microsoft.com>,
"K . Y . Srinivasan" <kys@microsoft.com>,
Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
shradhagupta@linux.microsoft.com, ernis@linux.microsoft.com,
stephen@networkplumber.org, netdev@vger.kernel.org,
linux-rdma@vger.kernel.org, linux-hyperv@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] net: mana: Cap MSI-X vectors to the device MSI-X table size
Date: Mon, 24 Aug 2026 17:16:58 +0100 [thread overview]
Message-ID: <20260824161658.GY265046@horms.kernel.org> (raw)
In-Reply-To: <20260821183736.733296-1-longli@microsoft.com>
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 <longli@microsoft.com>
Reviewed-by: Simon Horman <horms@kernel.org>
next prev parent reply other threads:[~2026-08-24 16:17 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-21 18:37 [PATCH net] net: mana: Cap MSI-X vectors to the device MSI-X table size Long Li
2026-08-24 16:16 ` Simon Horman [this message]
2026-08-24 19:10 ` patchwork-bot+netdevbpf
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