Re: [PATCH 1/2] sh_eth: Fix sleeping function called from invalid context

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Yoshihiro Kaneko <ykaneko0929@gmail.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Simon Horman <horms@verge.net.au>,
	Magnus Damm <magnus.damm@gmail.com>,
	Linux-sh list <linux-sh@vger.kernel.org>
Subject: Re: [PATCH 1/2] sh_eth: Fix sleeping function called from invalid context
Date: Tue, 25 Nov 2014 13:35:53 +0000	[thread overview]
Message-ID: <CAMuHMdWJYuXES4g1-=H6xo=gVePPSUkybUhL0VjuKk7asE6syg@mail.gmail.com> (raw)
In-Reply-To: <1415862135-27972-2-git-send-email-ykaneko0929@gmail.com>

Hi Kaneko-san,

On Thu, Nov 13, 2014 at 8:02 AM, Yoshihiro Kaneko <ykaneko0929@gmail.com> wrote:
> From: Mitsuhiro Kimura <mitsuhiro.kimura.kc@renesas.com>
>
> Fix the bug as follows:
>
> ----
> [ 1238.161349] BUG: sleeping function called from invalid context at drivers/base/power/runtime.c:952
> [ 1238.188279] in_atomic(): 1, irqs_disabled(): 0, pid: 1388, name: cat
> [ 1238.207425] CPU: 0 PID: 1388 Comm: cat Not tainted 3.10.31-ltsi-00046-gefa0b46 #1087
> [ 1238.230737] Backtrace:
> [ 1238.238123] [<c0012e64>] (dump_backtrace+0x0/0x10c) from [<c0013000>] (show_stack+0x18/0x1c)
> [ 1238.263499]  r6:000003b8 r5:c06160c0 r4:c0669e00 r3:00404000
> [ 1238.280583] [<c0012fe8>] (show_stack+0x0/0x1c) from [<c04515a4>] (dump_stack+0x20/0x28)
> [ 1238.304631] [<c0451584>] (dump_stack+0x0/0x28) from [<c004970c>] (__might_sleep+0xf8/0x118)
> [ 1238.329734] [<c0049614>] (__might_sleep+0x0/0x118) from [<c02465ac>] (__pm_runtime_resume+0x38/0x90)
> [ 1238.357170]  r7:d616f000 r6:c049c458 r5:00000004 r4:d6a17210
> [ 1238.374251] [<c0246574>] (__pm_runtime_resume+0x0/0x90) from [<c029b1c4>] (sh_eth_get_stats+0x44/0x280)
> [ 1238.402468]  r7:d616f000 r6:c049c458 r5:d5c21000 r4:d5c21000
> [ 1238.419552] [<c029b180>] (sh_eth_get_stats+0x0/0x280) from [<c03ae39c>] (dev_get_stats+0x54/0x88)
> [ 1238.446204]  r5:d5c21000 r4:d5ed7e08
> [ 1238.456980] [<c03ae348>] (dev_get_stats+0x0/0x88) from [<c03c677c>] (netstat_show.isra.15+0x54/0x9c)
> [ 1238.484413]  r6:d5c21000 r5:d5c21238 r4:00000028 r3:00000001
> [ 1238.501495] [<c03c6728>] (netstat_show.isra.15+0x0/0x9c) from [<c03c69b8>] (show_tx_errors+0x18/0x1c)
> [ 1238.529196]  r7:d5f945d8 r6:d5f945c0 r5:c049716c r4:c0650e7c
> [ 1238.546279] [<c03c69a0>] (show_tx_errors+0x0/0x1c) from [<c023963c>] (dev_attr_show+0x24/0x50)
> [ 1238.572157] [<c0239618>] (dev_attr_show+0x0/0x50) from [<c010c148>] (sysfs_read_file+0xb0/0x140)
> [ 1238.598554]  r5:c049716c r4:d5c21240
> [ 1238.609326] [<c010c098>] (sysfs_read_file+0x0/0x140) from [<c00b9ee4>] (vfs_read+0xb0/0x13c)
> [ 1238.634679] [<c00b9e34>] (vfs_read+0x0/0x13c) from [<c00ba0ac>] (SyS_read+0x44/0x74)
> [ 1238.657944]  r8:bef45bf0 r7:00000000 r6:d6ac0600 r5:00000000 r4:00000000
> [ 1238.678172] [<c00ba068>] (SyS_read+0x0/0x74) from [<c000eec0>] (ret_fast_syscall+0x0/0x30)
> ----
>
> Signed-off-by: Mitsuhiro Kimura <mitsuhiro.kimura.kc@renesas.com>
> Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
> ---
>  drivers/net/ethernet/renesas/sh_eth.c | 64 +++++++++++++++++++----------------
>  drivers/net/ethernet/renesas/sh_eth.h |  1 +
>  2 files changed, 36 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
> index 60e9c2c..862a691 100644
> --- a/drivers/net/ethernet/renesas/sh_eth.c
> +++ b/drivers/net/ethernet/renesas/sh_eth.c
> @@ -2042,6 +2042,8 @@ static int sh_eth_open(struct net_device *ndev)
>         if (ret)
>                 goto out_free_irq;
>
> +       mdp->is_opened = 1;
> +
>         return ret;
>
>  out_free_irq:
> @@ -2131,6 +2133,36 @@ static int sh_eth_start_xmit(struct sk_buff *skb, struct net_device *ndev)
>         return NETDEV_TX_OK;
>  }
>
> +static struct net_device_stats *sh_eth_get_stats(struct net_device *ndev)
> +{
> +       struct sh_eth_private *mdp = netdev_priv(ndev);
> +
> +       if (sh_eth_is_rz_fast_ether(mdp))
> +               return &ndev->stats;
> +
> +       if (!mdp->is_opened)

Can't you use netif_running(ndev) instead?

That way you don't need the is_opened field and track open/close
calls.

> --- a/drivers/net/ethernet/renesas/sh_eth.h
> +++ b/drivers/net/ethernet/renesas/sh_eth.h
> @@ -508,6 +508,7 @@ struct sh_eth_private {
>         u32 rx_buf_sz;                  /* Based on MTU+slack. */
>         int edmac_endian;
>         struct napi_struct napi;
> +       bool is_opened;
>         /* MII transceiver section. */
>         u32 phy_id;                     /* PHY ID */
>         struct mii_bus *mii_bus;        /* MDIO bus control */

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds