Thread (11 messages) 11 messages, 3 authors, 2023-01-29

RE: [PATCH net, 1/2] net: mana: Fix hint value before free irq

From: Haiyang Zhang <haiyangz@microsoft.com>
Date: 2023-01-29 18:54:38
Also in: linux-hyperv, lkml, stable

-----Original Message-----
From: Michael Kelley (LINUX) <redacted>
Sent: Sunday, January 29, 2023 9:26 AM
To: Haiyang Zhang <haiyangz@microsoft.com>; linux-hyperv@vger.kernel.org;
netdev@vger.kernel.org
Cc: Haiyang Zhang <haiyangz@microsoft.com>; Dexuan Cui
[off-list ref]; KY Srinivasan [off-list ref]; Paul Rosswurm
[off-list ref]; olaf@aepfle.de; vkuznets@redhat.com;
davem@davemloft.net; linux-kernel@vger.kernel.org; stable@vger.kernel.org
Subject: RE: [PATCH net, 1/2] net: mana: Fix hint value before free irq

From: LKML haiyangz <redacted> On Behalf Of Haiyang Zhang
Sent: Thursday, January 26, 2023 1:05 PM
quoted
Need to clear affinity_hint before free_irq(), otherwise there is a
one-time warning and stack trace during module unloading.

To fix this bug, set affinity_hint to NULL before free as required.

Cc: stable@vger.kernel.org
Fixes: 71fa6887eeca ("net: mana: Assign interrupts to CPUs based on NUMA
nodes")
quoted
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
---
 drivers/net/ethernet/microsoft/mana/gdma_main.c | 5 +++++
 1 file changed, 5 insertions(+)
diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c
b/drivers/net/ethernet/microsoft/mana/gdma_main.c
index b144f2237748..3bae9d4c1f08 100644
--- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
+++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
@@ -1297,6 +1297,8 @@ static int mana_gd_setup_irqs(struct pci_dev
*pdev)
quoted
 	for (j = i - 1; j >= 0; j--) {
 		irq = pci_irq_vector(pdev, j);
 		gic = &gc->irq_contexts[j];
+
+		irq_update_affinity_hint(irq, NULL);
 		free_irq(irq, gic);
 	}
@@ -1324,6 +1326,9 @@ static void mana_gd_remove_irqs(struct pci_dev
*pdev)
quoted
 			continue;

 		gic = &gc->irq_contexts[i];
+
+		/* Need to clear the hint before free_irq */
+		irq_update_affinity_hint(irq, NULL);
 		free_irq(irq, gic);
 	}

--
2.25.1
I think this patch should be folded into the second patch of this series.  While
this patch makes the warning go away, it doesn't really solve any problems by
itself.  It just papers over the warning.  My first reaction on seeing this patch
is that the warning exists because the memory for the mask likely had
been incorrectly managed, which is exactly the case.  Since this patch doesn't
really fix a problem on its own, I'd say merge it into the second patch.

That's just my $.02.  If you really want to keep it separate, that's not a
blocker for me.
Will do.

Thanks,
- Haiyang
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