Messages in this thread | | | From | Pascal Terjan <> | Date | Fri, 10 Jun 2022 15:00:14 +0000 | Subject | Re: [PATCH] vboxguest: add missing devm_free_irq |
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On Fri, 10 Jun 2022 at 13:50, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > On Thu, Jun 09, 2022 at 02:40:57PM +0100, Pascal Terjan wrote: > > This fixes the following warning when unloading the module: > > > > [249348.837181] remove_proc_entry: removing non-empty directory 'irq/20', leaking at least 'vboxguest' > > [249348.837219] WARNING: CPU: 0 PID: 6708 at fs/proc/generic.c:715 remove_proc_entry+0x119/0x140 > > > > [249348.837379] Call Trace: > > [249348.837385] unregister_irq_proc+0xbd/0xe0 > > [249348.837392] free_desc+0x23/0x60 > > [249348.837396] irq_free_descs+0x4a/0x70 > > [249348.837401] irq_domain_free_irqs+0x160/0x1a0 > > [249348.837452] mp_unmap_irq+0x5c/0x60 > > [249348.837458] acpi_unregister_gsi_ioapic+0x29/0x40 > > [249348.837463] acpi_unregister_gsi+0x17/0x30 > > [249348.837467] acpi_pci_irq_disable+0xbf/0xe0 > > [249348.837473] pcibios_disable_device+0x20/0x30 > > [249348.837478] pci_disable_device+0xef/0x120 > > [249348.837482] vbg_pci_remove+0x6c/0x70 [vboxguest] > > > > Signed-off-by: Pascal Terjan <pterjan@google.com> > > --- > > drivers/virt/vboxguest/vboxguest_linux.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/virt/vboxguest/vboxguest_linux.c b/drivers/virt/vboxguest/vboxguest_linux.c > > index 6e8c0f1c1056..faa4bc9f625c 100644 > > --- a/drivers/virt/vboxguest/vboxguest_linux.c > > +++ b/drivers/virt/vboxguest/vboxguest_linux.c > > @@ -423,6 +423,7 @@ static void vbg_pci_remove(struct pci_dev *pci) > > vbg_gdev = NULL; > > mutex_unlock(&vbg_gdev_mutex); > > > > + devm_free_irq(gdev->dev, pci->irq, gdev); > > The whope point of using devm_* calls is so you don't have to do stuff > like this. Perhaps this should not be using devm_() for the irq at all?
My initial assumption was that some sort of dependency was missing somewhere to ensure this gets freed first, but I failed to find any documentation on how this is supposed to work, so I went with a fix that would work.
But you are obviously right, if we manually free it in the normal path then using devm_{request,free}_irq sounds like just overhead without benefits.
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