From: Gabriel Krisman Bertazi krisman@linux.vnet.ibm.com
This patch has been added to the stable tree. If you have any objections, please let us know.
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[ Upstream commit c130b666a9a711f985a0a44b58699ebe14bb7245 ]
Commit f209fa03fc9d ("serial: 8250_pci: Detach low-level driver during PCI error recovery") introduces a potential use-after-free in case the pciserial_init_ports call in serial8250_io_resume fails, which may happen if a memory allocation fails or if the .init quirk failed for whatever reason). If this happen, further pci_get_drvdata will return a pointer to freed memory.
This patch reworks the PCI recovery resume hook to restore the old priv structure in this case, which should be ok, since the ports were already detached. Such error during recovery causes us to give up on the recovery.
Fixes: f209fa03fc9d ("serial: 8250_pci: Detach low-level driver during PCI error recovery") Reported-by: Michal Suchanek msuchanek@suse.com Signed-off-by: Gabriel Krisman Bertazi krisman@linux.vnet.ibm.com Signed-off-by: Guilherme G. Piccoli gpiccoli@linux.vnet.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- drivers/tty/serial/8250/8250_pci.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c index bfd5e2afaeaf..933961968ec9 100644 --- a/drivers/tty/serial/8250/8250_pci.c +++ b/drivers/tty/serial/8250/8250_pci.c @@ -5967,17 +5967,15 @@ static pci_ers_result_t serial8250_io_slot_reset(struct pci_dev *dev) static void serial8250_io_resume(struct pci_dev *dev) { struct serial_private *priv = pci_get_drvdata(dev); - const struct pciserial_board *board; + struct serial_private *new;
if (!priv) return;
- board = priv->board; - kfree(priv); - priv = pciserial_init_ports(dev, board); - - if (!IS_ERR(priv)) { - pci_set_drvdata(dev, priv); + new = pciserial_init_ports(dev, priv->board); + if (!IS_ERR(new)) { + pci_set_drvdata(dev, new); + kfree(priv); } }