Re: [Intel-wired-lan] [PATCH v2] e1000e: free IRQ regardless of __E1000_DOWN

From: Baicar, Tyler
Date: Mon Nov 21 2016 - 15:40:33 EST

On 11/17/2016 6:31 AM, Neftin, Sasha wrote:
On 11/13/2016 10:34 AM, Neftin, Sasha wrote:
On 11/11/2016 12:35 AM, Baicar, Tyler wrote:
Hello Sasha,

On 11/9/2016 11:19 PM, Neftin, Sasha wrote:
On 11/9/2016 11:41 PM, Tyler Baicar wrote:
Move IRQ free code so that it will happen regardless of the
__E1000_DOWN bit. Currently the e1000e driver only releases its IRQ
if the __E1000_DOWN bit is cleared. This is not sufficient because
it is possible for __E1000_DOWN to be set without releasing the IRQ.
In such a situation, we will hit a kernel bug later in e1000_remove
because the IRQ still has action since it was never freed. A
secondary bus reset can cause this case to happen.

Signed-off-by: Tyler Baicar <tbaicar@xxxxxxxxxxxxxx>
drivers/net/ethernet/intel/e1000e/netdev.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c
index 7017281..36cfcb0 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -4679,12 +4679,13 @@ int e1000e_close(struct net_device *netdev)
if (!test_bit(__E1000_DOWN, &adapter->state)) {
e1000e_down(adapter, true);
- e1000_free_irq(adapter);
/* Link status message must follow this format */
pr_info("%s NIC Link is Down\n", adapter->netdev->name);
+ e1000_free_irq(adapter);

I would like not recommend insert this change. This change related
driver state machine, we afraid from lot of synchronization problem and
We need keep e1000_free_irq in loop and check for 'test_bit' ready.
What do you mean here? There is no loop. If __E1000_DOWN is set then we
will never free the IRQ.

Another point, does before execute secondary bus reset your SW back up
pcie configuration space as properly?
After a secondary bus reset, the link needs to recover and go back to a
working state after 1 second.

From the callstack, the issue is happening while removing the endpoint
from the system, before applying the secondary bus reset.

The order of events is
1. remove the drivers
2. cause a secondary bus reset
3. wait 1 second
Actually, this is too much, usually link up in less than 100ms.You can
check Data Link Layer indication.
4. recover the link



Hello Tyler,
Okay, we need consult more about this suggestion.
May I ask what is setup you run? Is there NIC or on board LAN? I would
like try reproduce this issue in our lab's too.
Also, is same issue observed with same scenario and others NIC's too?
Intel-wired-lan mailing list

Hello Tyler,
I see some in consistent implementation of __*_close methods in our
drivers. Do you have any igb NIC to check if same problem persist there?
Hello Sasha,

I couldn't find an igb NIC to test with, but I did find another e1000e card that does not cause the same issue. That card is:

0004:01:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection
Subsystem: Intel Corporation Gigabit CT Desktop Adapter
Physical Slot: 5-1
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx+
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 0, Cache Line Size: 64 bytes
Interrupt: pin A routed to IRQ 299
Region 0: Memory at c01001c0000 (32-bit, non-prefetchable) [size=128K]
Region 1: Memory at c0100100000 (32-bit, non-prefetchable) [size=512K]
Region 2: I/O ports at 1000 [size=32]
Region 3: Memory at c01001e0000 (32-bit, non-prefetchable) [size=16K]
Expansion ROM at c0100180000 [disabled] [size=256K]
Capabilities: [c8] Power Management version 2
Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=1 PME-
Capabilities: [d0] MSI: Enable+ Count=1/1 Maskable- 64bit+
Address: 00000000397f0040 Data: 0000
Capabilities: [e0] Express (v1) Endpoint, MSI 00
DevCap: MaxPayload 256 bytes, PhantFunc 0, Latency L0s <512ns, L1 <64us
ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset-
DevCtl: Report errors: Correctable+ Non-Fatal+ Fatal+ Unsupported+
RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+
MaxPayload 256 bytes, MaxReadReq 512 bytes
DevSta: CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr+ TransPend-
LnkCap: Port #8, Speed 2.5GT/s, Width x1, ASPM L0s L1, Exit Latency L0s <128ns, L1 <64us
ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp-
LnkCtl: ASPM L1 Enabled; RCB 64 bytes Disabled- CommClk+
ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
LnkSta: Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
Capabilities: [a0] MSI-X: Enable- Count=5 Masked-
Vector table: BAR=3 offset=00000000
PBA: BAR=3 offset=00002000
Capabilities: [100 v1] Advanced Error Reporting
UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
UESvrt: DLP+ SDES- TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr-
CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+
AERCap: First Error Pointer: 00, GenCap- CGenEn- ChkCap- ChkEn-
Capabilities: [140 v1] Device Serial Number 68-05-ca-ff-ff-29-47-34
Kernel driver in use: e1000e

Here are the kernel logs from first running the test on this card and then running the test on the Intel 82571EB card that I originally found the issue with (you can see the issue doesn't happen on this card but does on the other):

[ 44.146749] ACPI: \_SB_.PCI0: Device has suffered a power fault
[ 44.155238] pcieport 0000:00:00.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, id=0000(Requester ID)
[ 44.166111] pcieport 0000:00:00.0: device [17cb:0400] error status/mask=00004000/00400000
[ 44.174420] pcieport 0000:00:00.0: [14] Completion Timeout (First)
[ 44.401943] e1000e 0000:01:00.0 eth0: Timesync Tx Control register not set as expected
[ 82.445586] pcieport 0002:00:00.0: PCIe Bus Error: severity=Corrected, type=Physical Layer, id=0000(Receiver ID)
[ 82.454851] pcieport 0002:00:00.0: device [17cb:0400] error status/mask=00000001/00006000
[ 82.463209] pcieport 0002:00:00.0: [ 0] Receiver Error
[ 82.469355] pcieport 0002:00:00.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, id=0000(Requester ID)
[ 82.481026] pcieport 0002:00:00.0: device [17cb:0400] error status/mask=00004000/00400000
[ 82.489343] pcieport 0002:00:00.0: [14] Completion Timeout (First)
[ 82.504573] ACPI: \_SB_.PCI2: Device has suffered a power fault
[ 84.528036] kernel BUG at drivers/pci/msi.c:369!

I'm not sure why it reproduces on the 82571EB card and not the 82574L card. The only obvious difference is there is no Reciever Error on the 82574L card.

If you have a patch fixing the inconsistencies you mentioned with the __*_close methods I would certainly be willing to test it out!


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