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 <[email protected]>
---
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(-)
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);
base-commit: 09162bc32c880a791c6c0668ce0745cf7958f576
--
2.28.0
The driver core ignores the return value of struct device_driver::remove
(because in general there is nothing that can be done about that). So
add a warning when an spi driver returns an error.
This simplifies the quest to make struct device_driver::remove return void.
A consequent change would be to make struct spi_driver::remove return void,
but I'm keeping this quest for later (or someone else).
Signed-off-by: Uwe Kleine-König <[email protected]>
---
drivers/spi/spi.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index e8c0a000ee19..6b7c19bf7715 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -408,13 +408,20 @@ static int spi_probe(struct device *dev)
static int spi_remove(struct device *dev)
{
const struct spi_driver *sdrv = to_spi_driver(dev->driver);
- int ret = 0;
- if (sdrv->remove)
+ if (sdrv->remove) {
+ int ret;
+
ret = sdrv->remove(to_spi_device(dev));
+ if (ret)
+ dev_warn(dev,
+ "Failed to unbind driver (%pe), ignoring\n",
+ ERR_PTR(ret));
+ }
+
dev_pm_domain_detach(dev, true);
- return ret;
+ return 0;
}
static void spi_shutdown(struct device *dev)
--
2.28.0
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 <[email protected]>
---
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));
}
+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);
--
2.28.0
Hello Marek,
On Tue, Nov 24, 2020 at 01:03:25PM +0100, Marek Szyprowski wrote:
> On 19.11.2020 17:16, Uwe Kleine-K?nig 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 <[email protected]>
>
> 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-K?nig |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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 <[email protected]>
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
On Tue, Nov 24, 2020 at 02:01:07PM +0100, Uwe Kleine-K?nig 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).