From: Timur Tabi Date: Thu, 29 Mar 2018 18:29:12 +0000 (-0500) Subject: gpioib: do not free unrequested descriptors X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=0f40bb84e25e591e35741979c578ce931818308b;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git gpioib: do not free unrequested descriptors commit ab3dbcf78f60f46d6a0ad63b1f4b690b7a427140 upstream. If the main loop in linehandle_create() encounters an error, it unwinds completely by freeing all previously requested GPIO descriptors. However, if the error occurs in the beginning of the loop before that GPIO is requested, then the exit code attempts to free a null descriptor. If extrachecks is enabled, gpiod_free() triggers a WARN_ON. Instead, keep a separate count of legitimate GPIOs so that only those are freed. Cc: stable@vger.kernel.org Fixes: d7c51b47ac11 ("gpio: userspace ABI for reading/writing GPIO lines") Reviewed-by: Bjorn Andersson Signed-off-by: Timur Tabi Signed-off-by: Linus Walleij Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index b4c8b25453a6..65f751adb1cd 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -443,7 +443,7 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip) struct gpiohandle_request handlereq; struct linehandle_state *lh; struct file *file; - int fd, i, ret; + int fd, i, count = 0, ret; if (copy_from_user(&handlereq, ip, sizeof(handlereq))) return -EFAULT; @@ -489,6 +489,7 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip) if (ret) goto out_free_descs; lh->descs[i] = desc; + count = i; if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW) set_bit(FLAG_ACTIVE_LOW, &desc->flags); @@ -555,7 +556,7 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip) out_put_unused_fd: put_unused_fd(fd); out_free_descs: - for (; i >= 0; i--) + for (i = 0; i < count; i++) gpiod_free(lh->descs[i]); kfree(lh->label); out_free_lh: