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| author | Long Li <longli@microsoft.com> | 2026-08-21 11:37:36 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-08-24 12:00:31 -0700 |
| commit | 2c7493f980140a5c40eb4f98f97c557193a2c330 (patch) | |
| tree | 46e6a4e6cb5dbdf4b6ec91bf84353bcd18715e92 /drivers/net | |
| parent | 5b483f7791b079bb97d411f1066652ff659207ff (diff) | |
| download | lwn-2c7493f980140a5c40eb4f98f97c557193a2c330.tar.gz lwn-2c7493f980140a5c40eb4f98f97c557193a2c330.zip | |
net: mana: Cap MSI-X vectors to the device MSI-X table size
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>
Link: https://patch.msgid.link/20260821183736.733296-1-longli@microsoft.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/ethernet/microsoft/mana/gdma_main.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c index ed9af314e4ed..f92b2d0bf926 100644 --- a/drivers/net/ethernet/microsoft/mana/gdma_main.c +++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c @@ -182,6 +182,7 @@ static int mana_gd_query_max_resources(struct pci_dev *pdev) struct gdma_query_max_resources_resp resp = {}; struct gdma_general_req req = {}; unsigned int max_num_queues; + unsigned int msix_vec_count; u8 bm_hostmode; u16 num_ports; int err; @@ -218,6 +219,24 @@ static int mana_gd_query_max_resources(struct pci_dev *pdev) gc->num_msix_usable = min(resp.max_msix, num_online_cpus() + 1); } + /* MSI-X vectors are allocated by index into the device MSI-X table, so + * never ask for more than the table holds. It can be smaller than both + * resp.max_msix and the CPU count. + */ + err = pci_msix_vec_count(pdev); + if (err <= 0) { + dev_err(gc->dev, "Failed to query MSI-X table size: %d\n", err); + return err < 0 ? err : -ENOSPC; + } + msix_vec_count = err; + + if (gc->num_msix_usable > msix_vec_count) { + dev_info(gc->dev, + "Limiting MSI-X vectors from %u to table size %u\n", + gc->num_msix_usable, msix_vec_count); + gc->num_msix_usable = msix_vec_count; + } + if (gc->num_msix_usable <= 1) return -ENOSPC; |