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| author | Kent Gibson <warthog618@gmail.com> | 2022-07-06 16:45:07 +0800 |
|---|---|---|
| committer | Bartosz Golaszewski <brgl@bgdev.pl> | 2022-07-07 12:18:18 +0200 |
| commit | c8e27a4a5136e7230f9e4ffcf132705bf56864cc (patch) | |
| tree | 76b9c9125ccfb8459b96efd4e84951ac978adc9e | |
| parent | 8af3a0b23818af59971f538bf258c15e1033ea55 (diff) | |
| download | lwn-c8e27a4a5136e7230f9e4ffcf132705bf56864cc.tar.gz lwn-c8e27a4a5136e7230f9e4ffcf132705bf56864cc.zip | |
gpiolib: cdev: fix null pointer dereference in linereq_free()
Fix a kernel NULL pointer dereference reported by gpio kselftests.
linereq_free() can be called as part of the cleanup of a failed request,
at which time the desc for a line may not have been determined, so it
is unsafe to dereference without a check.
Add a check prior to dereferencing the line desc.
Fixes: 2068339a6c35 ("gpiolib: cdev: Add hardware timestamp clock type")
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
| -rw-r--r-- | drivers/gpio/gpiolib-cdev.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index f5aa5f93342a..0c9a63becfef 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -1460,11 +1460,12 @@ static ssize_t linereq_read(struct file *file, static void linereq_free(struct linereq *lr) { unsigned int i; - bool hte; + bool hte = false; for (i = 0; i < lr->num_lines; i++) { - hte = !!test_bit(FLAG_EVENT_CLOCK_HTE, - &lr->lines[i].desc->flags); + if (lr->lines[i].desc) + hte = !!test_bit(FLAG_EVENT_CLOCK_HTE, + &lr->lines[i].desc->flags); edge_detector_stop(&lr->lines[i], hte); if (lr->lines[i].desc) gpiod_free(lr->lines[i].desc); |