summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2022-04-09 18:17:43 -1000
committerLinus Torvalds <torvalds@linux-foundation.org>2022-04-09 18:17:43 -1000
commitfa3b895da8e06d6e3dcf3e6941a3fd428343e3d7 (patch)
tree251dbd45b10536a157ff75e3835733c47a939e19
parente1f700ebd6bea293abe3c7e2807b252018efde01 (diff)
parent5467801f1fcbdc46bc7298a84dbf3ca1ff2a7320 (diff)
downloadlinux-fa3b895da8e06d6e3dcf3e6941a3fd428343e3d7.tar.bz2
Merge tag 'gpio-fixes-for-v5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux
Pull gpio fix from Bartosz Golaszewski: - fix a race condition with consumers accessing the fields of GPIO IRQ chips before they're fully initialized * tag 'gpio-fixes-for-v5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: gpio: Restrict usage of GPIO chip irq members before initialization
-rw-r--r--drivers/gpio/gpiolib.c19
-rw-r--r--include/linux/gpio/driver.h9
2 files changed, 28 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e59884cc12a7..085348e08986 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1404,6 +1404,16 @@ static int gpiochip_to_irq(struct gpio_chip *gc, unsigned int offset)
{
struct irq_domain *domain = gc->irq.domain;
+#ifdef CONFIG_GPIOLIB_IRQCHIP
+ /*
+ * Avoid race condition with other code, which tries to lookup
+ * an IRQ before the irqchip has been properly registered,
+ * i.e. while gpiochip is still being brought up.
+ */
+ if (!gc->irq.initialized)
+ return -EPROBE_DEFER;
+#endif
+
if (!gpiochip_irqchip_irq_valid(gc, offset))
return -ENXIO;
@@ -1593,6 +1603,15 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc,
acpi_gpiochip_request_interrupts(gc);
+ /*
+ * Using barrier() here to prevent compiler from reordering
+ * gc->irq.initialized before initialization of above
+ * GPIO chip irq members.
+ */
+ barrier();
+
+ gc->irq.initialized = true;
+
return 0;
}
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 98c93510640e..874aabd270c9 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -222,6 +222,15 @@ struct gpio_irq_chip {
bool per_parent_data;
/**
+ * @initialized:
+ *
+ * Flag to track GPIO chip irq member's initialization.
+ * This flag will make sure GPIO chip irq members are not used
+ * before they are initialized.
+ */
+ bool initialized;
+
+ /**
* @init_hw: optional routine to initialize hardware before
* an IRQ chip will be added. This is quite useful when
* a particular driver wants to clear IRQ related registers