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SubjectRe: BUG: bad unlock balance detected! e1000e
On Tue, Dec 09, 2008 at 03:08:01PM -0800, Andrew Morton wrote:
> On Tue, 9 Dec 2008 12:03:37 +0100
> Frederik Deweerdt <frederik.deweerdt@xprog.eu> wrote:
>
> > It some error checking is missing in e1000e: debug contention on NVM
> > SWFLAG
> > On Mon, Dec 08, 2008 at 12:24:09PM +0100, Zdenek Kabelac wrote:
> > > Hi
> > >
> > > During occasional scan of message log - I've found out this BUG which
> > > happened on Dec3 with the -rc7 from that day.
> > > (So if it's now fixed in current git feel free to ignore :))
> > >
> > > My machine T61 - C2D, 2GB, 64bit kernel - message appeared during
> > > shutdown and was actually not noticed by me...
> > >
> > >
> > > NetworkManager: <WARN> nm_signal_handler(): Caught signal 15,
> > > shutting down normally.
> > > NetworkManager: <info> (eth0): now unmanaged
> > > NetworkManager: <info> (eth0): device state change: 3 -> 1
> > > NetworkManager: <info> (eth0): cleaning up...
> > > NetworkManager: <info> (eth0): taking down device.
> > >
> > > =====================================
> > > [ BUG: bad unlock balance detected! ]
> > > -------------------------------------
>
> (top-posting repaired. Please don't do that!!!).
Yep, sorry.
>
> > Hello Zdenek,
> >
> > This could be due to 717d438d1fde94decef874b9808379d1f4523453
> > "e1000e: debug contention on NVM SWFLAG"
> > Error handling is missing from e1000_reset_hw_ich8lan so it may happen
> > that we don't acquire the nvm_mutex if the card times out.
> >
> > Adding Thomas to CC.
>
> yup. 2.6.27 needs fixing also.
>
> Like this?
I don't think so, e1000_acquire_swflag_ich8lan() locks and
e1000_release_swflag_ich8lan() unlocks. I think it is more along the
lines of:


diff --git a/drivers/net/e1000e/ich8lan.c b/drivers/net/e1000e/ich8lan.c
index 523b971..f971b83 100644
--- a/drivers/net/e1000e/ich8lan.c
+++ b/drivers/net/e1000e/ich8lan.c
@@ -1892,7 +1892,13 @@ static s32 e1000_reset_hw_ich8lan(struct e1000_hw *hw)
*/
ctrl |= E1000_CTRL_PHY_RST;
}
+
ret_val = e1000_acquire_swflag_ich8lan(hw);
+ if (ret_val) {
+ hw_dbg(hw, "Failed to acquire NVM swflag");
+ return ret_val;
+ }
+
hw_dbg(hw, "Issuing a global reset to ich8lan");
ew32(CTRL, (ctrl | E1000_CTRL_RST));
msleep(20);

But I'm not sure we should cancel the ongoing reset if the card times
out...


Regards,
Frederik

>
> From: Andrew Morton <akpm@linux-foundation.org>
>
> =====================================
> [ BUG: bad unlock balance detected! ]
> -------------------------------------
>
> A regression added by 717d438d1fde94decef874b9808379d1f4523453 ("e1000e:
> debug contention on NVM SWFLAG").
>
> Reported-by: "Zdenek Kabelac" <zdenek.kabelac@gmail.com>
> Cc: Frederik Deweerdt <frederik.deweerdt@xprog.eu>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: <stable@kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
> drivers/net/e1000e/ich8lan.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff -puN drivers/net/e1000e/ich8lan.c~drivers-net-e1000e-ich8lanc-fix-locking drivers/net/e1000e/ich8lan.c
> --- a/drivers/net/e1000e/ich8lan.c~drivers-net-e1000e-ich8lanc-fix-locking
> +++ a/drivers/net/e1000e/ich8lan.c
> @@ -400,6 +400,7 @@ static s32 e1000_acquire_swflag_ich8lan(
> {
> u32 extcnf_ctrl;
> u32 timeout = PHY_CFG_TIMEOUT;
> + s32 ret = 0;
>
> might_sleep();
>
> @@ -427,11 +428,11 @@ static s32 e1000_acquire_swflag_ich8lan(
> extcnf_ctrl &= ~E1000_EXTCNF_CTRL_SWFLAG;
> ew32(EXTCNF_CTRL, extcnf_ctrl);
> nvm_owner = -1;
> - mutex_unlock(&nvm_mutex);
> - return -E1000_ERR_CONFIG;
> + ret = -E1000_ERR_CONFIG;
> }
>
> - return 0;
> + mutex_unlock(&nvm_mutex);
> + return ret;
> }
>
> /**
> _
>


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