diff options
| author | Prashanth K <quic_prashk@quicinc.com> | 2023-02-13 23:00:38 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-02-14 14:41:32 +0100 |
| commit | 5ec63fdbca604568890c577753c6f66c5b3ef0b5 (patch) | |
| tree | 3d6f4add2c406a79c571ed405b7c1e9c800a16c9 /drivers/usb/gadget | |
| parent | 7ebb605d2283fb2647b4fa82030307ce00bee436 (diff) | |
usb: gadget: u_serial: Add null pointer check in gserial_resume
Consider a case where gserial_disconnect has already cleared
gser->ioport. And if a wakeup interrupt triggers afterwards,
gserial_resume gets called, which will lead to accessing of
gser->ioport and thus causing null pointer dereference.Add
a null pointer check to prevent this.
Added a static spinlock to prevent gser->ioport from becoming
null after the newly added check.
Fixes: aba3a8d01d62 ("usb: gadget: u_serial: add suspend resume callbacks")
Cc: stable <stable@kernel.org>
Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/1676309438-14922-1-git-send-email-quic_prashk@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/gadget')
| -rw-r--r-- | drivers/usb/gadget/function/u_serial.c | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c index 840626e064e1..a0ca47fbff0f 100644 --- a/drivers/usb/gadget/function/u_serial.c +++ b/drivers/usb/gadget/function/u_serial.c @@ -82,6 +82,9 @@ #define WRITE_BUF_SIZE 8192 /* TX only */ #define GS_CONSOLE_BUF_SIZE 8192 +/* Prevents race conditions while accessing gser->ioport */ +static DEFINE_SPINLOCK(serial_port_lock); + /* console info */ struct gs_console { struct console console; @@ -1375,8 +1378,10 @@ void gserial_disconnect(struct gserial *gser) if (!port) return; + spin_lock_irqsave(&serial_port_lock, flags); + /* tell the TTY glue not to do I/O here any more */ - spin_lock_irqsave(&port->port_lock, flags); + spin_lock(&port->port_lock); gs_console_disconnect(port); @@ -1391,7 +1396,8 @@ void gserial_disconnect(struct gserial *gser) tty_hangup(port->port.tty); } port->suspended = false; - spin_unlock_irqrestore(&port->port_lock, flags); + spin_unlock(&port->port_lock); + spin_unlock_irqrestore(&serial_port_lock, flags); /* disable endpoints, aborting down any active I/O */ usb_ep_disable(gser->out); @@ -1425,10 +1431,19 @@ EXPORT_SYMBOL_GPL(gserial_suspend); void gserial_resume(struct gserial *gser) { - struct gs_port *port = gser->ioport; + struct gs_port *port; unsigned long flags; - spin_lock_irqsave(&port->port_lock, flags); + spin_lock_irqsave(&serial_port_lock, flags); + port = gser->ioport; + + if (!port) { + spin_unlock_irqrestore(&serial_port_lock, flags); + return; + } + + spin_lock(&port->port_lock); + spin_unlock(&serial_port_lock); port->suspended = false; if (!port->start_delayed) { spin_unlock_irqrestore(&port->port_lock, flags); |