diff options
| author | Tong Zhang <ztong0001@gmail.com> | 2021-05-13 00:07:33 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-20 16:10:41 +0200 |
| commit | d2639ffdcad463b358b6bef8645ff81715daffcb (patch) | |
| tree | 80543124864c43166ddb9a2c58d41ec5f9709e27 /drivers/misc | |
| parent | 38660031e80eaa6cc9370b031c180612f414b00d (diff) | |
misc: alcor_pci: fix null-ptr-deref when there is no PCI bridge
[ Upstream commit 3ce3e45cc333da707d4d6eb433574b990bcc26f5 ]
There is an issue with the ASPM(optional) capability checking function.
A device might be attached to root complex directly, in this case,
bus->self(bridge) will be NULL, thus priv->parent_pdev is NULL.
Since alcor_pci_init_check_aspm(priv->parent_pdev) checks the PCI link's
ASPM capability and populate parent_cap_off, which will be used later by
alcor_pci_aspm_ctrl() to dynamically turn on/off device, what we can do
here is to avoid checking the capability if we are on the root complex.
This will make pdev_cap_off 0 and alcor_pci_aspm_ctrl() will simply
return when bring called, effectively disable ASPM for the device.
[ 1.246492] BUG: kernel NULL pointer dereference, address: 00000000000000c0
[ 1.248731] RIP: 0010:pci_read_config_byte+0x5/0x40
[ 1.253998] Call Trace:
[ 1.254131] ? alcor_pci_find_cap_offset.isra.0+0x3a/0x100 [alcor_pci]
[ 1.254476] alcor_pci_probe+0x169/0x2d5 [alcor_pci]
Co-developed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Link: https://lore.kernel.org/r/20210513040732.1310159-1-ztong0001@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/misc')
| -rw-r--r-- | drivers/misc/cardreader/alcor_pci.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/misc/cardreader/alcor_pci.c b/drivers/misc/cardreader/alcor_pci.c index 259fe1dfec03..afd409a5efae 100644 --- a/drivers/misc/cardreader/alcor_pci.c +++ b/drivers/misc/cardreader/alcor_pci.c @@ -133,7 +133,13 @@ static void alcor_pci_init_check_aspm(struct alcor_pci_priv *priv) u32 val32; priv->pdev_cap_off = alcor_pci_find_cap_offset(priv, priv->pdev); - priv->parent_cap_off = alcor_pci_find_cap_offset(priv, + /* + * A device might be attached to root complex directly and + * priv->parent_pdev will be NULL. In this case we don't check its + * capability and disable ASPM completely. + */ + if (!priv->parent_pdev) + priv->parent_cap_off = alcor_pci_find_cap_offset(priv, priv->parent_pdev); if ((priv->pdev_cap_off == 0) || (priv->parent_cap_off == 0)) { |