diff options
| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2026-03-05 00:36:39 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-03-11 16:18:48 +0100 |
| commit | ae4ff9dead5efa2025eddfcdb29411432bf40a7c (patch) | |
| tree | d4c0daaba0dd0cbaae1b33584f14e5345ce7b994 | |
| parent | d6d5febd12452b7fd951fdd15c3ec262f01901a4 (diff) | |
xhci: Fix NULL pointer dereference when reading portli debugfs files
Michal reported and debgged a NULL pointer dereference bug in the
recently added portli debugfs files
Oops is caused when there are more port registers counted in
xhci->max_ports than ports reported by Supported Protocol capabilities.
This is possible if max_ports is more than maximum port number, or
if there are gaps between ports of different speeds the 'Supported
Protocol' capabilities.
In such cases port->rhub will be NULL so we can't reach xhci behind it.
Add an explicit NULL check for this case, and print portli in hex
without dereferencing port->rhub.
Reported-by: Michal Pecio <michal.pecio@gmail.com>
Closes: https://lore.kernel.org/linux-usb/20260304103856.48b785fd.michal.pecio@gmail.com
Fixes: 384c57ec7205 ("usb: xhci: Add debugfs support for xHCI Port Link Info (PORTLI) register.")
Cc: stable@vger.kernel.org
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://patch.msgid.link/20260304223639.3882398-4-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/host/xhci-debugfs.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/usb/host/xhci-debugfs.c b/drivers/usb/host/xhci-debugfs.c index 890fc5e892f1..ade178ab34a7 100644 --- a/drivers/usb/host/xhci-debugfs.c +++ b/drivers/usb/host/xhci-debugfs.c @@ -386,11 +386,19 @@ static const struct file_operations port_fops = { static int xhci_portli_show(struct seq_file *s, void *unused) { struct xhci_port *port = s->private; - struct xhci_hcd *xhci = hcd_to_xhci(port->rhub->hcd); + struct xhci_hcd *xhci; u32 portli; portli = readl(&port->port_reg->portli); + /* port without protocol capability isn't added to a roothub */ + if (!port->rhub) { + seq_printf(s, "0x%08x\n", portli); + return 0; + } + + xhci = hcd_to_xhci(port->rhub->hcd); + /* PORTLI fields are valid if port is a USB3 or eUSB2V2 port */ if (port->rhub == &xhci->usb3_rhub) seq_printf(s, "0x%08x LEC=%u RLC=%u TLC=%u\n", portli, |