On Tue, Mar 15, 2022 at 12:38 PM Shreeya Patel
<shreeya.patel@xxxxxxxxxxxxx> wrote:
Thanks for the update, my comments below.
gc irq members are exposed before they could be completelygc --> GPIO chip
initialized and this leads to race conditions.Any example here. like ~3-4 lines of the Oops in question?
One such issue was observed for the gc->irq.domain variable whichgc --> GPIO chip
was accessed through the I2C interface in gpiochip_to_irq() before
it could be initialized by gpiochip_add_irqchip(). This resulted in
Kernel NULL pointer dereference.
To avoid such scenarios, restrict usage of gc irq members before
they are completely initialized....
+ /*There are too many duplications. Why not simply call it 'initialized'?
+ * Using barrier() here to prevent compiler from reordering
+ * gc->irq.gc_irq_initialized before initialization of above
+ * gc irq members.
+ */
+ barrier();
+
+ gc->irq.gc_irq_initialized = true;
- if (gc->to_irq) {Why can't this check be added into gpiochip_to_irq() ?
+ if (gc->to_irq && gc->irq.gc_irq_initialized) {
if (!gc->irq.initialized)
return -ENXIO;
...
+ bool gc_irq_initialized;Can you move it closer to .init_hw so it will be weakly grouped by
logic similarities?
Also see above.