From: LKML haiyangz lkmlhyz@microsoft.com On Behalf Of Haiyang Zhang Sent: Wednesday, February 1, 2023 1:47 PM

After calling irq_set_affinity_and_hint(), the cpumask pointer is saved in desc->affinity_hint, and will be used later when reading /proc/irq/<num>/affinity_hint. So the cpumask variable needs to be persistent. Otherwise, we are accessing freed memory when reading the affinity_hint file.

Also, need to clear affinity_hint before free_irq(), otherwise there is a one-time warning and stack trace during module unloading:

[ 243.948687] WARNING: CPU: 10 PID: 1589 at kernel/irq/manage.c:1913 free_irq+0x318/0x360 ... [ 243.948753] Call Trace: [ 243.948754] <TASK> [ 243.948760] mana_gd_remove_irqs+0x78/0xc0 [mana] [ 243.948767] mana_gd_remove+0x3e/0x80 [mana] [ 243.948773] pci_device_remove+0x3d/0xb0 [ 243.948778] device_remove+0x46/0x70 [ 243.948782] device_release_driver_internal+0x1fe/0x280 [ 243.948785] driver_detach+0x4e/0xa0 [ 243.948787] bus_remove_driver+0x70/0xf0 [ 243.948789] driver_unregister+0x35/0x60 [ 243.948792] pci_unregister_driver+0x44/0x90 [ 243.948794] mana_driver_exit+0x14/0x3fe [mana] [ 243.948800] __do_sys_delete_module.constprop.0+0x185/0x2f0

To fix the bug, use the persistent mask, cpumask_of(cpu#), and set affinity_hint to NULL before freeing the IRQ, as required by free_irq().

Cc: stable@vger.kernel.org Fixes: 71fa6887eeca ("net: mana: Assign interrupts to CPUs based on NUMA nodes") Signed-off-by: Haiyang Zhang haiyangz@microsoft.com

---

.../net/ethernet/microsoft/mana/gdma_main.c | 35 ++++++------------- 1 file changed, 10 insertions(+), 25 deletions(-)

diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c index b144f2237748..a55d42332e20 100644 --- a/drivers/net/ethernet/microsoft/mana/gdma_main.c +++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c @@ -1218,8 +1218,6 @@ static int mana_gd_setup_irqs(struct pci_dev *pdev) struct gdma_context *gc = pci_get_drvdata(pdev); struct gdma_irq_context *gic; unsigned int max_irqs;

• u16 *cpus;
• cpumask_var_t req_mask; int nvec, irq; int err, i = 0, j;

@@ -1240,21 +1238,7 @@ static int mana_gd_setup_irqs(struct pci_dev *pdev) goto free_irq_vector; }

• if (!zalloc_cpumask_var(&req_mask, GFP_KERNEL)) {

• err = -ENOMEM;
  

• goto free_irq;
  

• }
• cpus = kcalloc(nvec, sizeof(*cpus), GFP_KERNEL);
• if (!cpus) {

• err = -ENOMEM;
  

• goto free_mask;
  

• }
• for (i = 0; i < nvec; i++)

• cpus[i] = cpumask_local_spread(i, gc->numa_node);
  

• for (i = 0; i < nvec; i++) {

• cpumask_set_cpu(cpus[i], req_mask);
  

  gic = &gc->irq_contexts[i]; gic->handler = NULL; gic->arg = NULL;

@@ -1269,17 +1253,16 @@ static int mana_gd_setup_irqs(struct pci_dev *pdev) irq = pci_irq_vector(pdev, i); if (irq < 0) { err = irq;

• 	goto free_mask;
  

• 	goto free_irq;
  

  }

  err = request_irq(irq, mana_gd_intr, 0, gic->name, gic); if (err)

• 	goto free_mask;
  

• irq_set_affinity_and_hint(irq, req_mask);
  

• cpumask_clear(req_mask);
  

• 	goto free_irq;
  

• irq_set_affinity_and_hint(irq, cpumask_of(cpumask_local_spread
  

• 			  (i, gc->numa_node)));
  

  }

• free_cpumask_var(req_mask);

• kfree(cpus);

  err = mana_gd_alloc_res_map(nvec, &gc->msix_resource); if (err)

@@ -1290,13 +1273,12 @@ static int mana_gd_setup_irqs(struct pci_dev *pdev)

return 0;

-free_mask:

• free_cpumask_var(req_mask);
• kfree(cpus);

free_irq: 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 +1306,9 @@ static void mana_gd_remove_irqs(struct pci_dev *pdev) 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

Reviewed-by: Michael Kelley