LinuxLists.cc - [PATCH] dsa: Fix conversion from host device to mii bus

2014-10-17 19:31:06

Subject: [PATCH] dsa: Fix conversion from host device to mii bus

Commit b4d2394d01bc ("dsa: Replace mii_bus with a generic host device")
replaces mii_bus with a generic host_dev, and introduces
dsa_host_dev_to_mii_bus() to support conversion from host_dev to mii_bus.
However, in some cases it uses to_mii_bus to perform that conversion.
Since host_dev is not the phy bus device but typically a platform device,
this fails and results in a crash with the affected drivers.

BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff81781d35>] __mutex_lock_slowpath+0x75/0x100
PGD 406783067 PUD 406784067 PMD 0
Oops: 0002 [#1] SMP
...
Call Trace:
[<ffffffff810a538b>] ? pick_next_task_fair+0x61b/0x880
[<ffffffff81781de3>] mutex_lock+0x23/0x37
[<ffffffff81533244>] mdiobus_read+0x34/0x60
[<ffffffff8153b95a>] __mv88e6xxx_reg_read+0x8a/0xa0
[<ffffffff8153b9bc>] mv88e6xxx_reg_read+0x4c/0xa0

Fixes: b4d2394d01bc ("dsa: Replace mii_bus with a generic host device")
Cc: Alexander Duyck <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>
---
drivers/net/dsa/mv88e6060.c | 16 ++++++++++++----
drivers/net/dsa/mv88e6xxx.c | 14 ++++++++++----
2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/drivers/net/dsa/mv88e6060.c b/drivers/net/dsa/mv88e6060.c
index 776e965..05b0ca3 100644
--- a/drivers/net/dsa/mv88e6060.c
+++ b/drivers/net/dsa/mv88e6060.c
@@ -21,8 +21,12 @@

static int reg_read(struct dsa_switch *ds, int addr, int reg)
{
- return mdiobus_read(to_mii_bus(ds->master_dev),
- ds->pd->sw_addr + addr, reg);
+ struct mii_bus *bus = dsa_host_dev_to_mii_bus(ds->master_dev);
+
+ if (bus == NULL)
+ return -EINVAL;
+
+ return mdiobus_read(bus, ds->pd->sw_addr + addr, reg);
}

#define REG_READ(addr, reg) \
@@ -38,8 +42,12 @@ static int reg_read(struct dsa_switch *ds, int addr, int reg)

static int reg_write(struct dsa_switch *ds, int addr, int reg, u16 val)
{
- return mdiobus_write(to_mii_bus(ds->master_dev),
- ds->pd->sw_addr + addr, reg, val);
+ struct mii_bus *bus = dsa_host_dev_to_mii_bus(ds->master_dev);
+
+ if (bus == NULL)
+ return -EINVAL;
+
+ return mdiobus_write(bus, ds->pd->sw_addr + addr, reg, val);
}

#define REG_WRITE(addr, reg, val) \
diff --git a/drivers/net/dsa/mv88e6xxx.c b/drivers/net/dsa/mv88e6xxx.c
index d6f6428..a6c90cf 100644
--- a/drivers/net/dsa/mv88e6xxx.c
+++ b/drivers/net/dsa/mv88e6xxx.c
@@ -75,11 +75,14 @@ int __mv88e6xxx_reg_read(struct mii_bus *bus, int sw_addr, int addr, int reg)
int mv88e6xxx_reg_read(struct dsa_switch *ds, int addr, int reg)
{
struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
+ struct mii_bus *bus = dsa_host_dev_to_mii_bus(ds->master_dev);
int ret;

+ if (bus == NULL)
+ return -EINVAL;
+
mutex_lock(&ps->smi_mutex);
- ret = __mv88e6xxx_reg_read(to_mii_bus(ds->master_dev),
- ds->pd->sw_addr, addr, reg);
+ ret = __mv88e6xxx_reg_read(bus, ds->pd->sw_addr, addr, reg);
mutex_unlock(&ps->smi_mutex);

return ret;
@@ -119,11 +122,14 @@ int __mv88e6xxx_reg_write(struct mii_bus *bus, int sw_addr, int addr,
int mv88e6xxx_reg_write(struct dsa_switch *ds, int addr, int reg, u16 val)
{
struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
+ struct mii_bus *bus = dsa_host_dev_to_mii_bus(ds->master_dev);
int ret;

+ if (bus == NULL)
+ return -EINVAL;
+
mutex_lock(&ps->smi_mutex);
- ret = __mv88e6xxx_reg_write(to_mii_bus(ds->master_dev),
- ds->pd->sw_addr, addr, reg, val);
+ ret = __mv88e6xxx_reg_write(bus, ds->pd->sw_addr, addr, reg, val);
mutex_unlock(&ps->smi_mutex);

return ret;
--
1.9.1

2014-10-17 23:02:12

by Alexander Duyck

[permalink] [raw]

Subject: Re: [PATCH] dsa: Fix conversion from host device to mii bus

2014-10-17 23:41:08

by Florian Fainelli

[permalink] [raw]

Subject: Re: [PATCH] dsa: Fix conversion from host device to mii bus

On 10/17/2014 12:30 PM, Guenter Roeck wrote:
> Commit b4d2394d01bc ("dsa: Replace mii_bus with a generic host device")
> replaces mii_bus with a generic host_dev, and introduces
> dsa_host_dev_to_mii_bus() to support conversion from host_dev to mii_bus.
> However, in some cases it uses to_mii_bus to perform that conversion.
> Since host_dev is not the phy bus device but typically a platform device,
> this fails and results in a crash with the affected drivers.
>
> BUG: unable to handle kernel NULL pointer dereference at (null)
> IP: [<ffffffff81781d35>] __mutex_lock_slowpath+0x75/0x100
> PGD 406783067 PUD 406784067 PMD 0
> Oops: 0002 [#1] SMP
> ...
> Call Trace:
> [<ffffffff810a538b>] ? pick_next_task_fair+0x61b/0x880
> [<ffffffff81781de3>] mutex_lock+0x23/0x37
> [<ffffffff81533244>] mdiobus_read+0x34/0x60
> [<ffffffff8153b95a>] __mv88e6xxx_reg_read+0x8a/0xa0
> [<ffffffff8153b9bc>] mv88e6xxx_reg_read+0x4c/0xa0
>
> Fixes: b4d2394d01bc ("dsa: Replace mii_bus with a generic host device")
> Cc: Alexander Duyck <[email protected]>
> Signed-off-by: Guenter Roeck <[email protected]>

Acked-by: Florian Fainelli <[email protected]>

> ---
> drivers/net/dsa/mv88e6060.c | 16 ++++++++++++----
> drivers/net/dsa/mv88e6xxx.c | 14 ++++++++++----
> 2 files changed, 22 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/dsa/mv88e6060.c b/drivers/net/dsa/mv88e6060.c
> index 776e965..05b0ca3 100644
> --- a/drivers/net/dsa/mv88e6060.c
> +++ b/drivers/net/dsa/mv88e6060.c
> @@ -21,8 +21,12 @@
>
> static int reg_read(struct dsa_switch *ds, int addr, int reg)
> {
> - return mdiobus_read(to_mii_bus(ds->master_dev),
> - ds->pd->sw_addr + addr, reg);
> + struct mii_bus *bus = dsa_host_dev_to_mii_bus(ds->master_dev);
> +
> + if (bus == NULL)
> + return -EINVAL;
> +
> + return mdiobus_read(bus, ds->pd->sw_addr + addr, reg);
> }
>
> #define REG_READ(addr, reg) \
> @@ -38,8 +42,12 @@ static int reg_read(struct dsa_switch *ds, int addr, int reg)
>
> static int reg_write(struct dsa_switch *ds, int addr, int reg, u16 val)
> {
> - return mdiobus_write(to_mii_bus(ds->master_dev),
> - ds->pd->sw_addr + addr, reg, val);
> + struct mii_bus *bus = dsa_host_dev_to_mii_bus(ds->master_dev);
> +
> + if (bus == NULL)
> + return -EINVAL;
> +
> + return mdiobus_write(bus, ds->pd->sw_addr + addr, reg, val);
> }
>
> #define REG_WRITE(addr, reg, val) \
> diff --git a/drivers/net/dsa/mv88e6xxx.c b/drivers/net/dsa/mv88e6xxx.c
> index d6f6428..a6c90cf 100644
> --- a/drivers/net/dsa/mv88e6xxx.c
> +++ b/drivers/net/dsa/mv88e6xxx.c
> @@ -75,11 +75,14 @@ int __mv88e6xxx_reg_read(struct mii_bus *bus, int sw_addr, int addr, int reg)
> int mv88e6xxx_reg_read(struct dsa_switch *ds, int addr, int reg)
> {
> struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
> + struct mii_bus *bus = dsa_host_dev_to_mii_bus(ds->master_dev);
> int ret;
>
> + if (bus == NULL)
> + return -EINVAL;
> +
> mutex_lock(&ps->smi_mutex);
> - ret = __mv88e6xxx_reg_read(to_mii_bus(ds->master_dev),
> - ds->pd->sw_addr, addr, reg);
> + ret = __mv88e6xxx_reg_read(bus, ds->pd->sw_addr, addr, reg);
> mutex_unlock(&ps->smi_mutex);
>
> return ret;
> @@ -119,11 +122,14 @@ int __mv88e6xxx_reg_write(struct mii_bus *bus, int sw_addr, int addr,
> int mv88e6xxx_reg_write(struct dsa_switch *ds, int addr, int reg, u16 val)
> {
> struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
> + struct mii_bus *bus = dsa_host_dev_to_mii_bus(ds->master_dev);
> int ret;
>
> + if (bus == NULL)
> + return -EINVAL;
> +
> mutex_lock(&ps->smi_mutex);
> - ret = __mv88e6xxx_reg_write(to_mii_bus(ds->master_dev),
> - ds->pd->sw_addr, addr, reg, val);
> + ret = __mv88e6xxx_reg_write(bus, ds->pd->sw_addr, addr, reg, val);
> mutex_unlock(&ps->smi_mutex);
>
> return ret;
>

2014-10-18 03:52:37

by David Miller

[permalink] [raw]

Subject: Re: [PATCH] dsa: Fix conversion from host device to mii bus

From: Guenter Roeck <[email protected]>
Date: Fri, 17 Oct 2014 12:30:58 -0700

> Commit b4d2394d01bc ("dsa: Replace mii_bus with a generic host device")
> replaces mii_bus with a generic host_dev, and introduces
> dsa_host_dev_to_mii_bus() to support conversion from host_dev to mii_bus.
> However, in some cases it uses to_mii_bus to perform that conversion.
> Since host_dev is not the phy bus device but typically a platform device,
> this fails and results in a crash with the affected drivers.
>
> BUG: unable to handle kernel NULL pointer dereference at (null)
> IP: [<ffffffff81781d35>] __mutex_lock_slowpath+0x75/0x100
> PGD 406783067 PUD 406784067 PMD 0
> Oops: 0002 [#1] SMP
> ...
> Call Trace:
> [<ffffffff810a538b>] ? pick_next_task_fair+0x61b/0x880
> [<ffffffff81781de3>] mutex_lock+0x23/0x37
> [<ffffffff81533244>] mdiobus_read+0x34/0x60
> [<ffffffff8153b95a>] __mv88e6xxx_reg_read+0x8a/0xa0
> [<ffffffff8153b9bc>] mv88e6xxx_reg_read+0x4c/0xa0
>
> Fixes: b4d2394d01bc ("dsa: Replace mii_bus with a generic host device")
> Cc: Alexander Duyck <[email protected]>
> Signed-off-by: Guenter Roeck <[email protected]>

Applied, thanks.