RE: [Intel-wired-lan] [PATCH net] e1000e: fix IRQ leak when request_irq() fails in e1000_request_msix()

[Kwapulinski, Piotr]

>-----Original Message-----
>From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf Of Jiayuan Chen
>Sent: Friday, June 26, 2026 10:39 AM
>To: netdev@xxxxxxxxxxxxxxx
>Cc: Jiayuan Chen <jiayuan.chen@xxxxxxxxx>; Nguyen, Anthony L <anthony.l.nguyen@xxxxxxxxx>; Kitszel, Przemyslaw <przemyslaw.kitszel@xxxxxxxxx>; Andrew Lunn <andrew+netdev@xxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; Eric Dumazet <edumazet@xxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>; Paolo Abeni <pabeni@xxxxxxxxxx>; Jeff Garzik <jgarzik@xxxxxxxxxx>; Bruce Allan <bruce.w.allan@xxxxxxxxx>; intel-wired-lan@xxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
>Subject: [Intel-wired-lan] [PATCH net] e1000e: fix IRQ leak when request_irq() fails in e1000_request_msix()
>
>An internal syzbot instance reported the warning below.
>
>comedi (comedi_parport) lets userspace request_irq() an arbitrary IRQ number and can thus grab one of e1000e's MSI-X vectors. When
>e1000_request_msix() then fails partway through, it returned without freeing the vectors it had already requested; pci_disable_msix() later tears those descriptors down while their irqaction is still attached, leaking the /proc/irq entry.
>
>Free the already requested IRQs on the error path.
>
>genirq: Flags mismatch irq 28. 00200000 (eth1-tx-0) vs. 00200000 (comedi_parport)
>
>remove_proc_entry: removing non-empty directory 'irq/27', leaking at least 'eth1-rx-0'
>WARNING: fs/proc/generic.c:742 at remove_proc_entry+0x436/0x560, CPU#3: ip/445 Modules linked in:
>CPU: 3 UID: 0 PID: 445 Comm: ip Not tainted 7.1.0+ #284 PREEMPT
>RIP: 0010:remove_proc_entry (fs/proc/generic.c:742 (discriminator 4))
>PKRU: 55555554
>Call Trace:
><TASK>
>unregister_irq_proc (kernel/irq/proc.c:406) free_desc (kernel/irq/irqdesc.c:482) irq_free_descs (kernel/irq/irqdesc.c:874 kernel/irq/irqdesc.c:865) irq_domain_free_irqs (kernel/irq/irqdomain.c:1917)
>msi_domain_free_locked.part.0 (kernel/irq/msi.c:1619 kernel/irq/msi.c:1645) msi_domain_free_irqs_all_locked (kernel/irq/msi.c:1632) pci_msi_teardown_msi_irqs (drivers/pci/msi/irqdomain.c:28) pci_free_msi_irqs (drivers/pci/msi/msi.c:925) pci_disable_msix (drivers/pci/msi/api.c:200 drivers/pci/msi/api.c:193) e1000_request_irq (drivers/net/ethernet/intel/e1000e/netdev.c:2028)
>e1000e_open (drivers/net/ethernet/intel/e1000e/netdev.c:4681)
>__dev_open (net/core/dev.c:1702)
>netif_change_flags (net/core/dev.c:9806)
>do_setlink.isra.0 (net/core/rtnetlink.c:3207 (discriminator 1)) rtnetlink_rcv_msg (net/core/rtnetlink.c:7068) netlink_rcv_skb (net/netlink/af_netlink.c:2556)
>
>Fixes: 4662e82b2cb4 ("e1000e: add support for new 82574L part")
>Signed-off-by: Jiayuan Chen <jiayuan.chen@xxxxxxxxx>
>Assisted-by: Claude:claude-opus-4-8
>---
> drivers/net/ethernet/intel/e1000e/netdev.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
>diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
>index 808e5cddd6a9..19b9823c5679 100644
>--- a/drivers/net/ethernet/intel/e1000e/netdev.c
>+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
>@@ -2099,7 +2099,7 @@ void e1000e_set_interrupt_capability(struct e1000_adapter *adapter)  static int e1000_request_msix(struct e1000_adapter *adapter)  {
> 	struct net_device *netdev = adapter->netdev;
>-	int err = 0, vector = 0;
>+	int err = 0, vector = 0, i;
Thank you for the patch.
I'd suggest to declare 'i' right in the loop, besides:
Reviewed-by: Piotr Kwapulinski <piotr.kwapulinski@xxxxxxxxx>

> 
> 	if (strlen(netdev->name) < (IFNAMSIZ - 5))
> 		snprintf(adapter->rx_ring->name,
>@@ -2111,7 +2111,7 @@ static int e1000_request_msix(struct e1000_adapter *adapter)
> 			  e1000_intr_msix_rx, 0, adapter->rx_ring->name,
> 			  netdev);
> 	if (err)
>-		return err;
>+		goto err_free;
> 	adapter->rx_ring->itr_register = adapter->hw.hw_addr +
> 	    E1000_EITR_82574(vector);
> 	adapter->rx_ring->itr_val = adapter->itr; @@ -2127,7 +2127,7 @@ static int e1000_request_msix(struct e1000_adapter *adapter)
> 			  e1000_intr_msix_tx, 0, adapter->tx_ring->name,
> 			  netdev);
> 	if (err)
>-		return err;
>+		goto err_free;
> 	adapter->tx_ring->itr_register = adapter->hw.hw_addr +
> 	    E1000_EITR_82574(vector);
> 	adapter->tx_ring->itr_val = adapter->itr; @@ -2136,11 +2136,16 @@ static int e1000_request_msix(struct e1000_adapter *adapter)
> 	err = request_irq(adapter->msix_entries[vector].vector,
> 			  e1000_msix_other, 0, netdev->name, netdev);
> 	if (err)
>-		return err;
>+		goto err_free;
> 
> 	e1000_configure_msix(adapter);
> 
> 	return 0;
>+
>+err_free:
>+	for (i = vector - 1; i >= 0; i--)
>+		free_irq(adapter->msix_entries[i].vector, netdev);
>+	return err;
> }
> 
> /**
>--
>2.43.0
>
>