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author | Radu Rendec <radu.rendec@gmail.com> | 2018-11-28 06:20:48 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-12-21 16:13:06 +0300 |
commit | e89aa818353bccf626c317f0dee0d1cd7cdc6772 (patch) | |
tree | 6e1078fb25808ce3fc611852b5c1810d23c0d66b /arch | |
parent | a28d5f3d9c08a160801754804490dbac4ef9e2e1 (diff) | |
download | linux-e89aa818353bccf626c317f0dee0d1cd7cdc6772.tar.xz |
powerpc/msi: Fix NULL pointer access in teardown code
commit 78e7b15e17ac175e7eed9e21c6f92d03d3b0a6fa upstream.
The arch_teardown_msi_irqs() function assumes that controller ops
pointers were already checked in arch_setup_msi_irqs(), but this
assumption is wrong: arch_teardown_msi_irqs() can be called even when
arch_setup_msi_irqs() returns an error (-ENOSYS).
This can happen in the following scenario:
- msi_capability_init() calls pci_msi_setup_msi_irqs()
- pci_msi_setup_msi_irqs() returns -ENOSYS
- msi_capability_init() notices the error and calls free_msi_irqs()
- free_msi_irqs() calls pci_msi_teardown_msi_irqs()
This is easier to see when CONFIG_PCI_MSI_IRQ_DOMAIN is not set and
pci_msi_setup_msi_irqs() and pci_msi_teardown_msi_irqs() are just
aliases to arch_setup_msi_irqs() and arch_teardown_msi_irqs().
The call to free_msi_irqs() upon pci_msi_setup_msi_irqs() failure
seems legit, as it does additional cleanup; e.g.
list_del(&entry->list) and kfree(entry) inside free_msi_irqs() do
happen (MSI descriptors are allocated before pci_msi_setup_msi_irqs()
is called and need to be cleaned up if that fails).
Fixes: 6b2fd7efeb88 ("PCI/MSI/PPC: Remove arch_msi_check_device()")
Cc: stable@vger.kernel.org # v3.18+
Signed-off-by: Radu Rendec <radu.rendec@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/powerpc/kernel/msi.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/msi.c b/arch/powerpc/kernel/msi.c index dab616a33b8d..f2197654be07 100644 --- a/arch/powerpc/kernel/msi.c +++ b/arch/powerpc/kernel/msi.c @@ -34,5 +34,10 @@ void arch_teardown_msi_irqs(struct pci_dev *dev) { struct pci_controller *phb = pci_bus_to_host(dev->bus); - phb->controller_ops.teardown_msi_irqs(dev); + /* + * We can be called even when arch_setup_msi_irqs() returns -ENOSYS, + * so check the pointer again. + */ + if (phb->controller_ops.teardown_msi_irqs) + phb->controller_ops.teardown_msi_irqs(dev); } |