lkml.org 
[lkml]   [2018]   [Nov]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH net] net: phy: mscc: fix deadlock in vsc85xx_default_config
Hi Andrew,

On Thu, Nov 22, 2018 at 08:28:37PM +0100, Andrew Lunn wrote:
> On Thu, Nov 22, 2018 at 02:12:32PM +0100, Quentin Schulz wrote:
> > The vsc85xx_default_config function called in the vsc85xx_config_init
> > function which is used by VSC8530, VSC8531, VSC8540 and VSC8541 PHYs
> > mistakenly calls phy_read and phy_write in-between phy_select_page and
> > phy_restore_page.
> >
> > phy_select_page and phy_restore_page actually take and release the MDIO
> > bus lock so __phy_write and __phy_read (which assume that you already
> > have the MDIO bus lock unlike phy_write and phy_read) should be used for
> > any call in between the two said functions.
> >
> > Let's fix this deadlock.
> >
> > Fixes: 6a0bfbbe20b0 ("net: phy: mscc: migrate to phy_select/restore_page functions")
> >
> > Signed-off-by: Quentin Schulz <quentin.schulz@bootlin.com>
> > ---
> > drivers/net/phy/mscc.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/phy/mscc.c b/drivers/net/phy/mscc.c
> > index 62269e578718..6856fe4d1a60 100644
> > --- a/drivers/net/phy/mscc.c
> > +++ b/drivers/net/phy/mscc.c
> > @@ -814,10 +814,10 @@ static int vsc85xx_default_config(struct phy_device *phydev)
> > if (rc < 0)
> > goto out_unlock;
> >
> > - reg_val = phy_read(phydev, MSCC_PHY_RGMII_CNTL);
> > + reg_val = __phy_read(phydev, MSCC_PHY_RGMII_CNTL);
> > reg_val &= ~(RGMII_RX_CLK_DELAY_MASK);
> > reg_val |= (RGMII_RX_CLK_DELAY_1_1_NS << RGMII_RX_CLK_DELAY_POS);
> > - phy_write(phydev, MSCC_PHY_RGMII_CNTL, reg_val);
> > + __phy_write(phydev, MSCC_PHY_RGMII_CNTL, reg_val);
>
> Hi Quentin
>
> You appear to be only accessing a single register, read/modify/write.
> I think you can use phy_modify_paged(), which will take care of all
> the locking for you.
>

Grmbl... Of course :)

Thanks,
Quentin
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2018-11-23 09:19    [W:0.036 / U:0.960 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site