linux-kernel - [PATCH v2] firewire: ohci: prevent leak of left-over IRQ on unbind

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Date: Thu, 29 Feb 2024 14:47:59 +0000
From: Edmund Raile <edmund.raile@...ton.me>
To: o-takashi@...amocchi.jp
Cc: linux1394-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org, Edmund Raile <edmund.raile@...ton.me>
Subject: [PATCH v2] firewire: ohci: prevent leak of left-over IRQ on unbind


Commit 5a95f1ded28691e6 ("firewire: ohci: use devres for requested IRQ")
also removed the call to free_irq() in pci_remove(), leading to a
leftover irq of devm_request_irq() at pci_disable_msi() in pci_remove()
when unbinding the driver from the device

remove_proc_entry: removing non-empty directory 'irq/136', leaking at
least 'firewire_ohci'
Call Trace:
 ? remove_proc_entry+0x19c/0x1c0
 ? __warn+0x81/0x130
 ? remove_proc_entry+0x19c/0x1c0
 ? report_bug+0x171/0x1a0
 ? console_unlock+0x78/0x120
 ? handle_bug+0x3c/0x80
 ? exc_invalid_op+0x17/0x70
 ? asm_exc_invalid_op+0x1a/0x20
 ? remove_proc_entry+0x19c/0x1c0
 unregister_irq_proc+0xf4/0x120
 free_desc+0x3d/0xe0
 ? kfree+0x29f/0x2f0
 irq_free_descs+0x47/0x70
 msi_domain_free_locked.part.0+0x19d/0x1d0
 msi_domain_free_irqs_all_locked+0x81/0xc0
 pci_free_msi_irqs+0x12/0x40
 pci_disable_msi+0x4c/0x60
 pci_remove+0x9d/0xc0 [firewire_ohci
     01b483699bebf9cb07a3d69df0aa2bee71db1b26]
 pci_device_remove+0x37/0xa0
 device_release_driver_internal+0x19f/0x200
 unbind_store+0xa1/0xb0

remove irq with devm_free_irq() before pci_disable_msi()
also remove it in fail_msi: of pci_probe() as this would lead to
an identical leak

Fixes: 5a95f1ded28691e6 ("firewire: ohci: use devres for requested IRQ")

Signed-off-by: Edmund Raile <edmund.raile@...ton.me>

---

Using FW643 with vfio-pci required unbinding from firewire_ohci,
doing so currently produces a memory leak due to a leftover irq
which this patch removes.

The irq can be observed while the driver is loaded and bound:
find /proc/irq -type d -name "firewire_ohci"

Is it a good idea to submit a patch to devm_request_irq() in
include/linux/interrupt.h to add the function comment
/*
 * counterpart: devm_free_irq()
 */
so LSPs show that hint?

v2 change: corrected patch title

 drivers/firewire/ohci.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 9db9290c3269..7bc71f4be64a 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -3773,6 +3773,7 @@ static int pci_probe(struct pci_dev *dev,
 	return 0;
 
  fail_msi:
+	devm_free_irq(&dev->dev, dev->irq, ohci);
 	pci_disable_msi(dev);
 
 	return err;
@@ -3800,6 +3801,7 @@ static void pci_remove(struct pci_dev *dev)
 
 	software_reset(ohci);
 
+	devm_free_irq(&dev->dev, dev->irq, ohci);
 	pci_disable_msi(dev);
 
 	dev_notice(&dev->dev, "removing fw-ohci device\n");
-- 
2.43.0