From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: Re: [PATCH] dsa: Fix conversion from host device to mii bus Date: Fri, 17 Oct 2014 16:40:48 -0700 Message-ID: <5441A900.4030001@gmail.com> References: <1413574258-21766-1-git-send-email-linux@roeck-us.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: Alexander Duyck , netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Guenter Roeck , "David S. Miller" Return-path: In-Reply-To: <1413574258-21766-1-git-send-email-linux@roeck-us.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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: [] __mutex_lock_slowpath+0x75/0x100 > PGD 406783067 PUD 406784067 PMD 0 > Oops: 0002 [#1] SMP > ... > Call Trace: > [] ? pick_next_task_fair+0x61b/0x880 > [] mutex_lock+0x23/0x37 > [] mdiobus_read+0x34/0x60 > [] __mv88e6xxx_reg_read+0x8a/0xa0 > [] mv88e6xxx_reg_read+0x4c/0xa0 > > Fixes: b4d2394d01bc ("dsa: Replace mii_bus with a generic host device") > Cc: Alexander Duyck > Signed-off-by: Guenter Roeck Acked-by: Florian Fainelli > --- > 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; >