On Tue, Jul 28, 2015 at 10:45:26AM -0700, Duc Dang wrote:

On Tue, Jul 28, 2015 at 9:43 AM, Bjorn Helgaas [off-list ref] wrote:

quoted

On Fri, Jul 24, 2015 at 7:05 PM, Duc Dang [off-list ref] wrote:

quoted

Hi Bjorn,

On Fri, Jul 24, 2015 at 3:42 PM, Bjorn Helgaas [off-list ref] wrote:

quoted

I regularly see faults like this on an APM X-Gene:

  U-Boot 2013.04-mustang_sw_1.14.14 (Dec 16 2014 - 15:59:33)
  CPU0: APM ARM 64-bit Potenza Rev B0 2400MHz PCP 2400MHz
       32 KB ICACHE, 32 KB DCACHE
       SOC 2000MHz IOBAXI 400MHz AXI 250MHz AHB 200MHz GFC 125MHz
  ...
  Unhandled fault: synchronous external abort (0x96000010) at 0xffffff8000110034
  Internal error: : 96000010 [#1] SMP
  Modules linked in:
  CPU: 0 PID: 3723 Comm: ... 4.1.0-smp-DEV #3
  Hardware name: APM X-Gene Mustang board (DT)
  task: ffffffc7dc1a4140 ti: ffffffc7dc118000 task.ti: ffffffc7dc118000
  PC is at pci_generic_config_read32+0x4c/0xb8
  LR is at pci_generic_config_read32+0x40/0xb8
  pc : [<ffffffc00033b90c>] lr : [<ffffffc00033b900>] pstate: 600001c5
  ...
  Call trace:
  [<ffffffc00033b90c>] pci_generic_config_read32+0x4c/0xb8
  [<ffffffc00033bf58>] pci_user_read_config_byte+0x60/0xc4
  [<ffffffc0003496a8>] pci_read_config+0x15c/0x238
  [<ffffffc0002393b4>] sysfs_kf_bin_read+0x68/0xa0
  [<ffffffc00023896c>] kernfs_fop_read+0x9c/0x1ac
  [<ffffffc0001c361c>] __vfs_read+0x44/0x128
  [<ffffffc0001c3e28>] vfs_read+0x84/0x144
  [<ffffffc0001c4764>] SyS_read+0x50/0xb0

The log shows kernel gets an exception when trying to access Mellanox
card configuration space. This is usually due to suboptimal PCIe
SerDes parameters are using in your board, which will cause bad link
quality.
The PCIe SerDes programming is done in U-Boot, so I suggest you do a
U-Boot upgrade to our latest X-Gene U-Boot release.

I installed U-Boot 1.15.12, which I thought was the latest.  I'm still
seeing this issue regularly, approx once/hour.

Our latest U-Boot is 1.15.15, but U-Boot 1.15.12 is already a good
version to use. Are you running any PCIe traffic test when the error
happens? 

Nope, the machine was either idle or running a reboot test; no PCIe stress
test or anything.

And it will be useful if you can share your "lspci -vvv" output when
the board is running, we can check to see if there is any error status
reported.

Here's some lspci output and info about the firmware I'm running.
Obviously this lspci output was collected before a crash.  I have also
seen lspci output where "CESta: RxErr+" was set on the 00:00.0 Root Port.

U-Boot 2013.04-mustang_sw_1.15.12 (May 20 2015 - 10:03:33)

CPU0: APM ARM 64-bit Potenza Rev B0 2400MHz PCP 2400MHz
     32 KB ICACHE, 32 KB DCACHE
     SOC 2000MHz IOBAXI 400MHz AXI 250MHz AHB 200MHz GFC 125MHz
Boot from SPI-NOR
Slimpro FW:
        Ver: 2.4 (build 01.15.12.00 2015/05/20)
        PMD: 970 mV
        SOC: 950 mV
Board: Mustang - AppliedMicro APM883208-xNA24SPT Reference Board
I2C:   ready
DRAM:  ECC 32 GiB @ 1600MHz
SF: Detected N25Q256 with page size 256 Bytes, total 32 MiB
MMC:   X-Gene SD/SDIO/eMMC: 0
PCIE0: (RC) X8 GEN-3 link up
  00:00.0     - 10e8:e004 - Bridge device
   01:00.0    - 15b3:1007 - Network controller

# lspci -vvv
00:00.0 PCI bridge: Applied Micro Circuits Corp. Device e004 (rev 04) (prog-if 00 [Normal decode])
	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
	Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
	I/O behind bridge: 0000f000-00000fff
	Memory behind bridge: 80000000-82ffffff
	Prefetchable memory behind bridge: 0000000083000000-00000000830fffff
	Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- <SERR- <PERR-
	BridgeCtl: Parity- SERR- NoISA- VGA- MAbort- >Reset- FastB2B-
		PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn-
	Capabilities: [40] Express (v2) Root Port (Slot+), MSI 00
		DevCap:	MaxPayload 512 bytes, PhantFunc 0, Latency L0s <1us, L1 unlimited
			ExtTag- 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 #0, Speed unknown, Width x8, ASPM L0s L1, Latency L0 unlimited, L1 unlimited
			ClockPM- Surprise+ LLActRep+ BwNot+
		LnkCtl:	ASPM Disabled; RCB 64 bytes Disabled- Retrain- CommClk+
			ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
		LnkSta:	Speed unknown, Width x8, TrErr- Train- SlotClk+ DLActive+ BWMgmt+ ABWMgmt-
		SltCap:	AttnBtn- PwrCtrl- MRL- AttnInd- PwrInd- HotPlug- Surprise-
			Slot #1, PowerLimit 10.000W; Interlock- NoCompl-
		SltCtl:	Enable: AttnBtn- PwrFlt- MRL- PresDet- CmdCplt- HPIrq- LinkChg-
			Control: AttnInd Off, PwrInd Off, Power- Interlock-
		SltSta:	Status: AttnBtn- PowerFlt- MRL- CmdCplt- PresDet- Interlock-
			Changed: MRL- PresDet- LinkState+
		RootCtl: ErrCorrectable- ErrNon-Fatal- ErrFatal- PMEIntEna- CRSVisible-
		RootCap: CRSVisible-
		RootSta: PME ReqID 0000, PMEStatus- PMEPending-
		DevCap2: Completion Timeout: Not Supported, TimeoutDis+ ARIFwd-
		DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis- ARIFwd-
		LnkCtl2: Target Link Speed: Unknown, EnterCompliance- SpeedDis-, Selectable De-emphasis: -3.5dB
			 Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
			 Compliance De-emphasis: -6dB
		LnkSta2: Current De-emphasis Level: -6dB
	Capabilities: [80] Power Management version 3
		Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
		Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
	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: [180 v1] #19
	Capabilities: [150 v1] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?>
	Kernel driver in use: pcieport

01:00.0 Ethernet controller: Mellanox Technologies MT27520 Family
	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-
	Interrupt: pin A routed to IRQ 226
	Region 0: [virtual] Memory at e182000000 (32-bit, non-prefetchable) [size=1M]
	Region 2: [virtual] Memory at e180000000 (32-bit, non-prefetchable) [size=32M]
	[virtual] Expansion ROM@e183000000 [disabled] [size=1M]
	Capabilities: [40] Power Management version 3
		Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
		Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
	Capabilities: [9c] MSI-X: Enable- Count=64 Masked-
		Vector table: BAR=0 offset=0007c000
		PBA: BAR=0 offset=0007d000
	Capabilities: [60] Express (v2) Endpoint, MSI 00
		DevCap:	MaxPayload 256 bytes, PhantFunc 0, Latency L0s <64ns, L1 unlimited
			ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset-
		DevCtl:	Report errors: Correctable- Non-Fatal- Fatal- Unsupported-
			RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop-
			MaxPayload 128 bytes, MaxReadReq 512 bytes
		DevSta:	CorrErr+ UncorrErr- FatalErr- UnsuppReq- AuxPwr- TransPend-
		LnkCap:	Port #8, Speed unknown, Width x8, ASPM L0s, Latency L0 unlimited, L1 unlimited
			ClockPM- Surprise- LLActRep- BwNot-
		LnkCtl:	ASPM Disabled; RCB 64 bytes Disabled- Retrain- CommClk-
			ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
		LnkSta:	Speed unknown, Width x8, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
		DevCap2: Completion Timeout: Range ABCD, TimeoutDis+
		DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-
		LnkCtl2: Target Link Speed: Unknown, EnterCompliance- SpeedDis-, Selectable De-emphasis: -6dB
			 Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
			 Compliance De-emphasis: -6dB
		LnkSta2: Current De-emphasis Level: -6dB
	Capabilities: [100 v1] Alternative Routing-ID Interpretation (ARI)
		ARICap:	MFVC- ACS-, Next Function: 0
		ARICtl:	MFVC- ACS-, Function Group: 0
	Capabilities: [148 v1] Device Serial Number xx-xx-xx-xx-xx-xx-xx-xx
	Capabilities: [154 v2] 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: [18c v1] #19
	Kernel modules: mlx4_core