On 2/18/24 02:52, Bartosz Golaszewski wrote:
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On Sat, 17 Feb 2024 19:35:43 +0100, Bartosz Golaszewski <brgl@xxxxxxxx> said:
On Sat, Feb 17, 2024 at 2:53 PM Xiaolei Wang <xiaolei.wang@xxxxxxxxxxxxx> wrote:
The changes in commit 1f2bcb8c8ccd ("gpio: protect the
descriptor label with SRCU"), desc_set_label has already
allocated memory space for the label, so there is no need
to allocate it again. otherwise memory leaks will be
introduced.
No, we *want* to copy it if it's not in .rodata for the same reason we
introduced SRCU. This may be a valid report but the fix is wrong.
unreferenced object 0xffff0000c3e4d0c0 (size 32):
comm "kworker/u16:4", pid 60, jiffies 4294894555
hex dump (first 32 bytes):
72 65 67 75 6c 61 74 6f 72 2d 63 61 6e 32 2d 73 regulator-can2-s
74 62 79 00 00 00 ff ff ff ff ff ff eb db ff ff tby.............
backtrace (crc 2c3a0350):
[<00000000e93c5cf4>] kmemleak_alloc+0x34/0x40
[<0000000097a2657f>] __kmalloc_node_track_caller+0x2c4/0x524
[<000000000dd1c057>] kstrdup+0x4c/0x98
[<00000000b513a96a>] kstrdup_const+0x34/0x40
[<000000008a7f0feb>] gpiod_request_commit+0xdc/0x358
[<00000000fc71ad64>] gpiod_request+0xd8/0x204
[<00000000fa24b091>] gpiod_find_and_request+0x170/0x780
[<0000000086ecf92d>] gpiod_get_index+0x70/0xe0
[<000000004aef97f9>] gpiod_get_optional+0x18/0x30
[<00000000312f1b25>] reg_fixed_voltage_probe+0x58c/0xad8
[<00000000e6f47635>] platform_probe+0xc4/0x198
[<00000000cf78fbdb>] really_probe+0x204/0x5a8
[<00000000e28d05ec>] __driver_probe_device+0x158/0x2c4
[<00000000e4fe452b>] driver_probe_device+0x60/0x18c
[<00000000479fcf5d>] __device_attach_driver+0x168/0x208
[<000000007d389f38>] bus_for_each_drv+0x104/0x190
Can you post the full kmemleak report for this, please?
Bart
Ah, I think I see the problem. Can you test the following diff:
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 02be0ba1a402..0fdd4ad242bd 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -695,10 +695,15 @@ EXPORT_SYMBOL_GPL(gpiochip_line_is_valid);
static void gpiodev_release(struct device *dev)
{
struct gpio_device *gdev = to_gpio_device(dev);
+ struct gpio_desc *desc;
unsigned int i;
- for (i = 0; i < gdev->ngpio; i++)
- cleanup_srcu_struct(&gdev->descs[i].srcu);
+ for (i = 0; i < gdev->ngpio; i++) {
+ desc = &gdev->descs[i];
+
+ kfree_const(desc->label);
+ cleanup_srcu_struct(&desc->srcu);
+ }
ida_free(&gpio_ida, gdev->id);
kfree_const(gdev->label);
and let me know if it fixes the issue?
I tried the following modifications, which did not fix the problem,
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 02be0ba1a402..5940ef88399c 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -695,10 +695,14 @@ EXPORT_SYMBOL_GPL(gpiochip_line_is_valid);
static void gpiodev_release(struct device *dev)
{
struct gpio_device *gdev = to_gpio_device(dev);
+ struct gpio_desc *desc;
unsigned int i;
- for (i = 0; i < gdev->ngpio; i++)
- cleanup_srcu_struct(&gdev->descs[i].srcu);
+ for (i = 0; i < gdev->ngpio; i++) {
+ desc = &gdev->descs[i];
+ kfree_const(desc->label);
+ cleanup_srcu_struct(&desc->srcu);
+ }
ida_free(&gpio_ida, gdev->id);
kfree_const(gdev->label);
unreferenced object 0xffff0000c0e83740 (size 32):
comm "kworker/u16:0", pid 10, jiffies 4294894561
hex dump (first 32 bytes):
72 65 67 75 6c 61 74 6f 72 2d 75 73 64 68 63 32 regulator-usdhc2
00 37 e8 c0 00 00 ff ff 00 00 00 00 00 00 00 00 .7..............
backtrace (crc 222fadd4):
[<00000000cd106dac>] kmemleak_alloc+0x34/0x40
[<00000000e084cf5f>] __kmalloc_node_track_caller+0x2c4/0x524
[<00000000746173b0>] kstrdup+0x4c/0x98
[<00000000f79b3bf4>] kstrdup_const+0x34/0x40
[<00000000f47eb728>] gpiod_request_commit+0xdc/0x358
[<000000003a6899af>] gpiod_request+0xd8/0x204
[<00000000c93118be>] gpiod_find_and_request+0x170/0x780
[<00000000660eebdd>] gpiod_get_index+0x70/0xe0
[<00000000eb599be3>] gpiod_get_optional+0x18/0x30
[<00000000e8b3cfcb>] reg_fixed_voltage_probe+0x58c/0xad8
[<000000009737579a>] platform_probe+0xc4/0x198
[<00000000405158e3>] really_probe+0x204/0x5a8
[<00000000772dd378>] __driver_probe_device+0x158/0x2c4
[<00000000ddc25aba>] driver_probe_device+0x60/0x18c
[<00000000cc4413ff>] __device_attach_driver+0x168/0x208
[<00000000e04f3755>] bus_for_each_drv+0x104/0x190
I'm a little confused. In the gpiod_request_commit() function, if label
is true, we allocate space kstrdup_const() for it, but desc_set_label()
will still be called. If label is true, space will be allocated to it
again, desc-> label will be pointed to the place where new is allocated,
thanks
xiaolei
Bart
Fixes: 1f2bcb8c8ccd ("gpio: protect the descriptor label with SRCU")
Signed-off-by: Xiaolei Wang <xiaolei.wang@xxxxxxxxxxxxx>
---
drivers/gpio/gpiolib.c | 6 ------
1 file changed, 6 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 02be0ba1a402..32191547dece 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2250,12 +2250,6 @@ static int gpiod_request_commit(struct gpio_desc *desc, const char *label)
if (test_and_set_bit(FLAG_REQUESTED, &desc->flags))
return -EBUSY;
- if (label) {
- label = kstrdup_const(label, GFP_KERNEL);
- if (!label)
- return -ENOMEM;
- }
-
/* NOTE: gpio_request() can be called in early boot,
* before IRQs are enabled, for non-sleeping (SOC) GPIOs.
*/
--
2.25.1
