Patchwork e1000e: fix double release of mutex

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Submitter Jeff Kirsher
Date Dec. 11, 2008, 9:58 p.m.
Message ID <20081211215806.1173.24413.stgit@lost.foo-projects.org>
Download mbox | patch
Permalink /patch/13585/
State Superseded
Delegated to: David Miller
Headers show

Comments

Jeff Kirsher - Dec. 11, 2008, 9:58 p.m.
During a reset, releasing the swflag after it failed to be acquired would
cause a double unlock of the mutex.  Instead, test whether acquisition of
the swflag was successful and if not, do not release the swflag.  The reset
must still be done to bring the device to a quiescent state.

This resolves [BUG 12200] BUG: bad unlock balance detected! e1000e
http://bugzilla.kernel.org/show_bug.cgi?id=12200

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---

 drivers/net/e1000e/ich8lan.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)


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David Miller - Dec. 12, 2008, 4:31 a.m.
From: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Date: Thu, 11 Dec 2008 13:58:07 -0800

> During a reset, releasing the swflag after it failed to be acquired would
> cause a double unlock of the mutex.  Instead, test whether acquisition of
> the swflag was successful and if not, do not release the swflag.  The reset
> must still be done to bring the device to a quiescent state.
> 
> This resolves [BUG 12200] BUG: bad unlock balance detected! e1000e
> http://bugzilla.kernel.org/show_bug.cgi?id=12200
> 
> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

If we're fixing a regression like this, you should make the
patch against net-2.6, and this one is against net-next-2.6

Please respin this for me, thanks Jeff.
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Jeff Kirsher - Dec. 12, 2008, 4:51 a.m.
On Thu, Dec 11, 2008 at 8:31 PM, David Miller <davem@davemloft.net> wrote:
> From: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
> Date: Thu, 11 Dec 2008 13:58:07 -0800
>
>> During a reset, releasing the swflag after it failed to be acquired would
>> cause a double unlock of the mutex.  Instead, test whether acquisition of
>> the swflag was successful and if not, do not release the swflag.  The reset
>> must still be done to bring the device to a quiescent state.
>>
>> This resolves [BUG 12200] BUG: bad unlock balance detected! e1000e
>> http://bugzilla.kernel.org/show_bug.cgi?id=12200
>>
>> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
>
> If we're fixing a regression like this, you should make the
> patch against net-2.6, and this one is against net-next-2.6
>
> Please respin this for me, thanks Jeff.
> --
>

Doh! Sorry Dave.  My bad, respinning now.

Patch

diff --git a/drivers/net/e1000e/ich8lan.c b/drivers/net/e1000e/ich8lan.c
index 92f2ace..f2a5963 100644
--- a/drivers/net/e1000e/ich8lan.c
+++ b/drivers/net/e1000e/ich8lan.c
@@ -1939,12 +1939,17 @@  static s32 e1000_reset_hw_ich8lan(struct e1000_hw *hw)
 		ctrl |= E1000_CTRL_PHY_RST;
 	}
 	ret_val = e1000_acquire_swflag_ich8lan(hw);
+	/* Whether or not the swflag was acquired, we need to reset the part */
 	hw_dbg(hw, "Issuing a global reset to ich8lan\n");
 	ew32(CTRL, (ctrl | E1000_CTRL_RST));
 	msleep(20);
 
-	/* release the swflag because it is not reset by hardware reset */
-	e1000_release_swflag_ich8lan(hw);
+	if (!ret_val) {
+		/* release the swflag because it is not reset by
+		 * hardware reset
+		 */
+		e1000_release_swflag_ich8lan(hw);
+	}
 
 	ret_val = e1000e_get_auto_rd_done(hw);
 	if (ret_val) {