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[3.5.y.z,extended,stable] Patch "iwlwifi: don't handle masked interrupt" has been added to staging queue

Message ID 1357591097-22011-1-git-send-email-herton.krzesinski@canonical.com
State New
Headers show

Commit Message

Herton Ronaldo Krzesinski Jan. 7, 2013, 8:38 p.m. UTC
This is a note to let you know that I have just added a patch titled

    iwlwifi: don't handle masked interrupt

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

From 3e8e8ab6e5cfd156d983d3b777c7552c57cda7da Mon Sep 17 00:00:00 2001
From: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Date: Wed, 28 Nov 2012 10:51:34 +0200
Subject: [PATCH] iwlwifi: don't handle masked interrupt

commit 25a172655f837bdb032e451f95441bb4acec51bb upstream.

This can lead to a panic if the driver isn't ready to
handle them. Since our interrupt line is shared, we can get
an interrupt at any time (and CONFIG_DEBUG_SHIRQ checks
that even when the interrupt is being freed).

If the op_mode has gone away, we musn't call it. To avoid
this the transport disables the interrupts when the hw is
stopped and the op_mode is leaving.
If there is an event that would cause an interrupt the INTA
register is updated regardless of the enablement of the
interrupts: even if the interrupts are disabled, the INTA
will be changed, but the device won't issue an interrupt.
But the ISR can be called at any time, so we ought ignore
the value in the INTA otherwise we can call the op_mode
after it was freed.

I found this bug when the op_mode_start failed, and called
iwl_trans_stop_hw(trans, true). Then I played with the
RFKILL button, and removed the module.
While removing the module, the IRQ is freed, and the ISR is
called (CONFIG_DEBUG_SHIRQ enabled). Panic.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Reviewed-by: Gregory Greenman <gregory.greenman@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
[ herton: code to patch is in drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c,
  under functions iwl_isr and iwl_isr_ict ]
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
---
 drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

--
1.7.9.5
diff mbox

Patch

diff --git a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
index f774778..34d35a7 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
@@ -919,12 +919,20 @@  static irqreturn_t iwl_isr(int irq, void *data)
 	 *    back-to-back ISRs and sporadic interrupts from our NIC.
 	 * If we have something to service, the tasklet will re-enable ints.
 	 * If we *don't* have something, we'll re-enable before leaving here. */
-	inta_mask = iwl_read32(trans, CSR_INT_MASK);  /* just for debug */
+	inta_mask = iwl_read32(trans, CSR_INT_MASK);
 	iwl_write32(trans, CSR_INT_MASK, 0x00000000);

 	/* Discover which interrupts are active/pending */
 	inta = iwl_read32(trans, CSR_INT);

+	if (inta & (~inta_mask)) {
+		IWL_DEBUG_ISR(trans,
+			      "We got a masked interrupt (0x%08x)...Ack and ignore\n",
+			      inta & (~inta_mask));
+		iwl_write32(trans, CSR_INT, inta & (~inta_mask));
+		inta &= inta_mask;
+	}
+
 	/* Ignore interrupt if there's nothing in NIC to service.
 	 * This may be due to IRQ shared with another device,
 	 * or due to sporadic interrupts thrown from our NIC. */
@@ -1008,7 +1016,7 @@  irqreturn_t iwl_isr_ict(int irq, void *data)
 	 * If we have something to service, the tasklet will re-enable ints.
 	 * If we *don't* have something, we'll re-enable before leaving here.
 	 */
-	inta_mask = iwl_read32(trans, CSR_INT_MASK);  /* just for debug */
+	inta_mask = iwl_read32(trans, CSR_INT_MASK);
 	iwl_write32(trans, CSR_INT_MASK, 0x00000000);