Re: [PATCH] iio: chemical: scd30: fix Oops due to missing parent device
From: Jonathan Cameron <jic23@kernel.org>
Date: 2021-02-12 19:13:25
Also in:
linux-iio, lkml
On Mon, 8 Feb 2021 23:39:47 +0100 Petr Štetiar [off-list ref] wrote:
My machine Oopsed while testing SCD30 sensor in interrupt driven mode:
Unable to handle kernel NULL pointer dereference at virtual address 00000188
pgd = (ptrval)
[00000188] *pgd=00000000
Internal error: Oops: 5 [#1] SMP ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.4.96+ #473
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
PC is at _raw_spin_lock_irqsave+0x10/0x4c
LR is at devres_add+0x18/0x38
...
[<8070ecac>] (_raw_spin_lock_irqsave) from [<804916a8>] (devres_add+0x18/0x38)
[<804916a8>] (devres_add) from [<805ef708>] (devm_iio_trigger_alloc+0x5c/0x7c)
[<805ef708>] (devm_iio_trigger_alloc) from [<805f0a90>] (scd30_probe+0x1d4/0x3f0)
[<805f0a90>] (scd30_probe) from [<805f10fc>] (scd30_i2c_probe+0x54/0x64)
[<805f10fc>] (scd30_i2c_probe) from [<80583390>] (i2c_device_probe+0x150/0x278)
[<80583390>] (i2c_device_probe) from [<8048e6c0>] (really_probe+0x1f8/0x360)
I've found out, that it's due to missing parent/owner device in iio_dev struct
which then leads to NULL pointer dereference during spinlock while registering
the device resource via devres_add().
Cc: <redacted> # v5.9+
Fixes: 64b3d8b1b0f5 ("iio: chemical: scd30: add core driver")
Signed-off-by: Petr Štetiar <redacted>Hi Petr, So, we moved this into the core a while back (to avoid exactly this sort of issue). That change predates this introduction of this driver as it went in in v5.8 So I think you've hit an issue with a backport here to an earlier kernel? Jonathan
quoted hunk ↗ jump to hunk
--- drivers/iio/chemical/scd30_core.c | 1 + 1 file changed, 1 insertion(+)diff --git a/drivers/iio/chemical/scd30_core.c b/drivers/iio/chemical/scd30_core.c index 4d0d798c7cd3..33aa6eb1963d 100644 --- a/drivers/iio/chemical/scd30_core.c +++ b/drivers/iio/chemical/scd30_core.c@@ -697,6 +697,7 @@ int scd30_probe(struct device *dev, int irq, const char *name, void *priv, dev_set_drvdata(dev, indio_dev); + indio_dev->dev.parent = dev; indio_dev->info = &scd30_info; indio_dev->name = name; indio_dev->channels = scd30_channels;