diff mbox series

[v2,1/3] spi: fix resource leak for drivers without .remove callback

Message ID 20201119161604.2633521-1-u.kleine-koenig@pengutronix.de
State Superseded
Headers show
Series [v2,1/3] spi: fix resource leak for drivers without .remove callback | expand

Commit Message

Uwe Kleine-König Nov. 19, 2020, 4:16 p.m. UTC 
Consider an spi driver with a .probe but without a .remove callback (e.g.
rtc-ds1347). The function spi_drv_probe() is called to bind a device and
so dev_pm_domain_attach() is called. As there is no remove callback
spi_drv_remove() isn't called at unbind time however and so calling
dev_pm_domain_detach() is missed and the pm domain keeps active.

To fix this always use both spi_drv_probe() and spi_drv_remove() and
make them handle the respective callback not being set. This has the
side effect that for a (hypothetical) driver that has neither .probe nor
remove the clk and pm domain setup is done.

Fixes: 33cf00e57082 ("spi: attach/detach SPI device to the ACPI power domain")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
Changes since (implicit) v1:

 - make use of spi_drv_probe and spi_drv_remove unconditionally.

 drivers/spi/spi.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)


base-commit: 09162bc32c880a791c6c0668ce0745cf7958f576

Comments

Marek Szyprowski Nov. 24, 2020, 12:03 p.m. UTC | #1 
Hi Uwe,

On 19.11.2020 17:16, Uwe Kleine-König wrote:
> The eventual goal is to get rid of the callbacks in struct

> device_driver. Other than not using driver callbacks there should be no

> side effect of this patch.

>

> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>


This patch landed recently in linux-next as commit 9db34ee64ce4 ("spi: 
Use bus_type functions for probe, remove and shutdown").

It causes a regression on some of my test boards:

Unable to handle kernel NULL pointer dereference at virtual address 
0000000000000018
Mem abort info:
   ESR = 0x96000004
   EC = 0x25: DABT (current EL), IL = 32 bits
   SET = 0, FnV = 0
   EA = 0, S1PTW = 0
Data abort info:
   ISV = 0, ISS = 0x00000004
   CM = 0, WnR = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=00000000318ed000
[0000000000000018] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 96000004 [#1] PREEMPT SMP
Modules linked in: cpufreq_powersave cpufreq_conservative brcmfmac 
brcmutil cfg80211 crct10dif_ce s3fwrn5_i2c s3fwrn5 nci nfc s5p_mfc 
s5p_jpeg hci_uart btqca btbc
buf2_dma_contig videobuf2_memops videobuf2_v4l2 bluetooth 
videobuf2_common videodev panfrost gpu_sched ecdh_generic mc ecc rfkill 
ip_tables x_tables ipv6
CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 
5.10.0-rc5-next-20201124+ #9771
Hardware name: Samsung TM2E board (DT)
pstate: 60000005 (nZCv daif -PAN -UAO -TCO BTYPE=--)
pc : spi_shutdown+0x10/0x38
lr : device_shutdown+0x10c/0x350
sp : ffff80001311bc70
...
Call trace:
  spi_shutdown+0x10/0x38
  kernel_restart_prepare+0x34/0x40
  kernel_restart+0x14/0x88
  __do_sys_reboot+0x148/0x248
  __arm64_sys_reboot+0x1c/0x28
  el0_svc_common.constprop.3+0x74/0x198
  do_el0_svc+0x20/0x98
  el0_sync_handler+0x140/0x1a8
  el0_sync+0x140/0x180
Code: f9403402 d1008041 f100005f 9a9f1021 (f9400c21)
---[ end trace 266c07205a2d632e ]---
Kernel panic - not syncing: Oops: Fatal exception
Kernel Offset: disabled
CPU features: 0x0240022,65006087
Memory Limit: none
---[ end Kernel panic - not syncing: Oops: Fatal exception ]---

> ---

>   drivers/spi/spi.c | 33 ++++++++++++++++-----------------

>   1 file changed, 16 insertions(+), 17 deletions(-)

>

> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c

> index 5becf6c2c409..e8c0a000ee19 100644

> --- a/drivers/spi/spi.c

> +++ b/drivers/spi/spi.c

> @@ -374,16 +374,7 @@ static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)

>   	return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);

>   }

>   

> -struct bus_type spi_bus_type = {

> -	.name		= "spi",

> -	.dev_groups	= spi_dev_groups,

> -	.match		= spi_match_device,

> -	.uevent		= spi_uevent,

> -};

> -EXPORT_SYMBOL_GPL(spi_bus_type);

> -

> -

> -static int spi_drv_probe(struct device *dev)

> +static int spi_probe(struct device *dev)

>   {

>   	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);

>   	struct spi_device		*spi = to_spi_device(dev);

> @@ -414,7 +405,7 @@ static int spi_drv_probe(struct device *dev)

>   	return ret;

>   }

>   

> -static int spi_drv_remove(struct device *dev)

> +static int spi_remove(struct device *dev)

>   {

>   	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);

>   	int ret = 0;

> @@ -426,13 +417,25 @@ static int spi_drv_remove(struct device *dev)

>   	return ret;

>   }

>   

> -static void spi_drv_shutdown(struct device *dev)

> +static void spi_shutdown(struct device *dev)

>   {

>   	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);

>   

> -	sdrv->shutdown(to_spi_device(dev));

> +	if (sdrv->shutdown)

> +		sdrv->shutdown(to_spi_device(dev));

>   }


In the above function dev->driver might be NULL, so its use in 
to_spi_driver() and sdrv->shutdown leads to NULL pointer dereference. I 
didn't check the details, but a simple check for NULL dev->driver and 
return is enough to fix this issue. I can send such fix if you want.

> +struct bus_type spi_bus_type = {

> +	.name		= "spi",

> +	.dev_groups	= spi_dev_groups,

> +	.match		= spi_match_device,

> +	.uevent		= spi_uevent,

> +	.probe		= spi_probe,

> +	.remove		= spi_remove,

> +	.shutdown	= spi_shutdown,

> +};

> +EXPORT_SYMBOL_GPL(spi_bus_type);

> +

>   /**

>    * __spi_register_driver - register a SPI driver

>    * @owner: owner module of the driver to register

> @@ -445,10 +448,6 @@ int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)

>   {

>   	sdrv->driver.owner = owner;

>   	sdrv->driver.bus = &spi_bus_type;

> -	sdrv->driver.probe = spi_drv_probe;

> -	sdrv->driver.remove = spi_drv_remove;

> -	if (sdrv->shutdown)

> -		sdrv->driver.shutdown = spi_drv_shutdown;

>   	return driver_register(&sdrv->driver);

>   }

>   EXPORT_SYMBOL_GPL(__spi_register_driver);


Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland
Uwe Kleine-König Nov. 24, 2020, 1:01 p.m. UTC | #2 
Hello Marek,

On Tue, Nov 24, 2020 at 01:03:25PM +0100, Marek Szyprowski wrote:
> On 19.11.2020 17:16, Uwe Kleine-König wrote:

> > The eventual goal is to get rid of the callbacks in struct

> > device_driver. Other than not using driver callbacks there should be no

> > side effect of this patch.

> >

> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

> 

> This patch landed recently in linux-next as commit 9db34ee64ce4 ("spi: 

> Use bus_type functions for probe, remove and shutdown").

> 

> It causes a regression on some of my test boards:

> 

> Unable to handle kernel NULL pointer dereference at virtual address 

> 0000000000000018

> Mem abort info:

>    ESR = 0x96000004

>    EC = 0x25: DABT (current EL), IL = 32 bits

>    SET = 0, FnV = 0

>    EA = 0, S1PTW = 0

> Data abort info:

>    ISV = 0, ISS = 0x00000004

>    CM = 0, WnR = 0

> user pgtable: 4k pages, 48-bit VAs, pgdp=00000000318ed000

> [0000000000000018] pgd=0000000000000000, p4d=0000000000000000

> Internal error: Oops: 96000004 [#1] PREEMPT SMP

> Modules linked in: cpufreq_powersave cpufreq_conservative brcmfmac 

> brcmutil cfg80211 crct10dif_ce s3fwrn5_i2c s3fwrn5 nci nfc s5p_mfc 

> s5p_jpeg hci_uart btqca btbc

> buf2_dma_contig videobuf2_memops videobuf2_v4l2 bluetooth 

> videobuf2_common videodev panfrost gpu_sched ecdh_generic mc ecc rfkill 

> ip_tables x_tables ipv6

> CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 

> 5.10.0-rc5-next-20201124+ #9771

> Hardware name: Samsung TM2E board (DT)

> pstate: 60000005 (nZCv daif -PAN -UAO -TCO BTYPE=--)

> pc : spi_shutdown+0x10/0x38

> lr : device_shutdown+0x10c/0x350

> sp : ffff80001311bc70

> ...

> Call trace:

>   spi_shutdown+0x10/0x38

>   kernel_restart_prepare+0x34/0x40

>   kernel_restart+0x14/0x88

>   __do_sys_reboot+0x148/0x248

>   __arm64_sys_reboot+0x1c/0x28

>   el0_svc_common.constprop.3+0x74/0x198

>   do_el0_svc+0x20/0x98

>   el0_sync_handler+0x140/0x1a8

>   el0_sync+0x140/0x180

> Code: f9403402 d1008041 f100005f 9a9f1021 (f9400c21)

> ---[ end trace 266c07205a2d632e ]---

> Kernel panic - not syncing: Oops: Fatal exception

> Kernel Offset: disabled

> CPU features: 0x0240022,65006087

> Memory Limit: none

> ---[ end Kernel panic - not syncing: Oops: Fatal exception ]---

> 

> > ---

> >   drivers/spi/spi.c | 33 ++++++++++++++++-----------------

> >   1 file changed, 16 insertions(+), 17 deletions(-)

> >

> > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c

> > index 5becf6c2c409..e8c0a000ee19 100644

> > --- a/drivers/spi/spi.c

> > +++ b/drivers/spi/spi.c

> > @@ -374,16 +374,7 @@ static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)

> >   	return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);

> >   }

> >   

> > -struct bus_type spi_bus_type = {

> > -	.name		= "spi",

> > -	.dev_groups	= spi_dev_groups,

> > -	.match		= spi_match_device,

> > -	.uevent		= spi_uevent,

> > -};

> > -EXPORT_SYMBOL_GPL(spi_bus_type);

> > -

> > -

> > -static int spi_drv_probe(struct device *dev)

> > +static int spi_probe(struct device *dev)

> >   {

> >   	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);

> >   	struct spi_device		*spi = to_spi_device(dev);

> > @@ -414,7 +405,7 @@ static int spi_drv_probe(struct device *dev)

> >   	return ret;

> >   }

> >   

> > -static int spi_drv_remove(struct device *dev)

> > +static int spi_remove(struct device *dev)

> >   {

> >   	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);

> >   	int ret = 0;

> > @@ -426,13 +417,25 @@ static int spi_drv_remove(struct device *dev)

> >   	return ret;

> >   }

> >   

> > -static void spi_drv_shutdown(struct device *dev)

> > +static void spi_shutdown(struct device *dev)

> >   {

> >   	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);

> >   

> > -	sdrv->shutdown(to_spi_device(dev));

> > +	if (sdrv->shutdown)

> > +		sdrv->shutdown(to_spi_device(dev));

> >   }

> 

> In the above function dev->driver might be NULL, so its use in 

> to_spi_driver() and sdrv->shutdown leads to NULL pointer dereference. I 

> didn't check the details, but a simple check for NULL dev->driver and 

> return is enough to fix this issue. I can send such fix if you want.


Ah, I see. shutdown is called for unbound devices, too. Assuming that
Mark prefers a fix on top instead of an updated patch: Yes, please send
a fix. Otherwise I can do this, too, as I introduced the problem.

Best regards and thanks,
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |
Mark Brown Nov. 24, 2020, 1:31 p.m. UTC | #3 
On Tue, Nov 24, 2020 at 02:01:07PM +0100, Uwe Kleine-König wrote:
> On Tue, Nov 24, 2020 at 01:03:25PM +0100, Marek Szyprowski wrote:


> > > +	if (sdrv->shutdown)

> > > +		sdrv->shutdown(to_spi_device(dev));

> > >   }


> > In the above function dev->driver might be NULL, so its use in 

> > to_spi_driver() and sdrv->shutdown leads to NULL pointer dereference. I 

> > didn't check the details, but a simple check for NULL dev->driver and 

> > return is enough to fix this issue. I can send such fix if you want.


> Ah, I see. shutdown is called for unbound devices, too. Assuming that

> Mark prefers a fix on top instead of an updated patch: Yes, please send

> a fix. Otherwise I can do this, too, as I introduced the problem.


Yes, please send an incremental fix (in general in a situation like this
I'd just send a fix as part of the original report, it's quicker if the
fix is OK).
diff mbox series

Patch

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 0cab239d8e7f..5becf6c2c409 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -405,9 +405,11 @@  static int spi_drv_probe(struct device *dev)
 	if (ret)
 		return ret;
 
-	ret = sdrv->probe(spi);
-	if (ret)
-		dev_pm_domain_detach(dev, true);
+	if (sdrv->probe) {
+		ret = sdrv->probe(spi);
+		if (ret)
+			dev_pm_domain_detach(dev, true);
+	}
 
 	return ret;
 }
@@ -415,9 +417,10 @@  static int spi_drv_probe(struct device *dev)
 static int spi_drv_remove(struct device *dev)
 {
 	const struct spi_driver		*sdrv = to_spi_driver(dev->driver);
-	int ret;
+	int ret = 0;
 
-	ret = sdrv->remove(to_spi_device(dev));
+	if (sdrv->remove)
+		ret = sdrv->remove(to_spi_device(dev));
 	dev_pm_domain_detach(dev, true);
 
 	return ret;
@@ -442,10 +445,8 @@  int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 {
 	sdrv->driver.owner = owner;
 	sdrv->driver.bus = &spi_bus_type;
-	if (sdrv->probe)
-		sdrv->driver.probe = spi_drv_probe;
-	if (sdrv->remove)
-		sdrv->driver.remove = spi_drv_remove;
+	sdrv->driver.probe = spi_drv_probe;
+	sdrv->driver.remove = spi_drv_remove;
 	if (sdrv->shutdown)
 		sdrv->driver.shutdown = spi_drv_shutdown;
 	return driver_register(&sdrv->driver);