Julian Margetson <runaway@xxxxxxxx> writes: > On 12/18/2015 10:34 PM, Andy Shevchenko wrote: >> On Sat, Dec 19, 2015 at 1:16 AM, Måns Rullgård <mans@xxxxxxxxx> wrote: >>> Julian Margetson <runaway@xxxxxxxx> writes: >>> >>>> On 12/18/2015 6:33 PM, Måns Rullgård wrote: >>>>> Julian Margetson <runaway@xxxxxxxx> writes: >>>>> >>>>>> On 12/18/2015 1:18 PM, Måns Rullgård wrote: >>>>>>> Julian Margetson <runaway@xxxxxxxx> writes: >>>>>>> >>>>>>>> On 12/18/2015 8:49 AM, Måns Rullgård wrote: >>>>>>>>> Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> writes: >>>>>>>>> >>>>>>>>>>>> [ 5.206125] Unable to handle kernel paging request for data at >>>>>>>>>>>> address 0x00000000 >>>>>>>>>>>> [ 5.228546] Faulting instruction address: 0xc043a2c8 >>>>>>>>>>>> [ 5.248577] Vector: 300 (Data Access) at [eddafae0] >>>>>>>>>>>> [ 5.268658] pc: c043a2c8: sata_dwc_qc_issue+0xb8/0x204 >>>>>>>>>>> Well, that's not good. Can you translate that address to a line of >>>>>>>>>>> code? >>>>>>>>>> Besides that, can you enable DYNAMIC_DEBUG in the config and append >>>>>>>>>> 'dw_dmac_core.dyndbg dw_dmac.dyndbg' to the kernel cmdline? >>>>>>>>> Enabling debug messages in the sata_dwc driver might also be informative. >>>>>>>>> >>>>>>>> Changed the sata-dwc to a module . >>>>>>>> >>>>>>>> [ 18.475140] sata-dwc 4bffd1000.sata: sata_dwc_qc_prep_by_tag: dma_dwc_xfer_setup returns NULL >>>>>>>> [ 18.535698] sata-dwc 4bffd1000.sata: sata_dwc_qc_prep_by_tag: dma_dwc_xfer_setup returns NULL >>>>>>> That's strange. The only way that can happen is if >>>>>>> dmaengine_prep_slave_sg() return NULL, and that really shouldn't be >>>>>>> happening. Did you turn on debug messages in dw_dma? You can enable >>>>>>> some extra debug messages by adding "#define VERBOSE_DEBUG" at the top >>>>>>> of drivers/dma/dw/core.c >>>>>>> >>>>>> [ 17.526173] sata-dwc 4bffd1000.sata: sata_dwc_qc_prep_by_tag: dma_dwc_xfer_setup returns NULL >>>>>> [ 17.600124] sata-dwc 4bffd1000.sata: sata_dwc_qc_prep_by_tag: dma_dwc_xfer_setup returns NULL >>>>>> [ 17.662978] sata-dwc 4bffd1000.sata: sata_dwc_qc_prep_by_tag: dma_dwc_xfer_setup returns NULL >>>>> Could you post the entire kernel log? There might be important >>>>> information before the errors start. >>>>> >>>> >>>> =~=~=~=~=~=~=~=~=~=~=~= PuTTY log 2015.12.18 15:01:48 =~=~=~=~=~=~=~=~=~=~=~= >>>> [ 0.000000] Using Canyonlands machine description >>>> [ 0.000000] Initializing cgroup subsys cpu >>>> [ 0.000000] Linux version 4.4.0-rc5-Sam460ex (root@julian-VirtualBox) (gcc version 4.8.2 (Ubuntu 4.8.2-16ubuntu3) ) #8 PREEMPT Fri Dec 18 13:36:34 AST 2015 >>>> [ 0.000000] Zone ranges: >>>> [ 0.000000] DMA [mem 0x0000000000000000-0x000000002fffffff] >>>> [ 0.000000] Normal empty >>>> [ 0.000000] HighMem [mem 0x0000000030000000-0x000000007fffffff] >>>> [ 0.000000] Movable zone start for each node >>>> [ 0.000000] Early memory node ranges >>>> [ 0.000000] node 0: [mem 0x0000000000000000-0x000000007fffffff] >>>> [ 0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x000000007fffffff] >>>> [ 0.000000] MMU: Allocated 1088 bytes of context maps for 255 contexts >>>> [ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 522752 >>>> [ 0.000000] Kernel command line: root=/dev/sda8 console=ttyS0,115200 console=tty0 dw_dmac_core.dyndbg dw_dmac.dyndbg >> I would suggest to use console=tty1 instead of console=tty0. >> >>> [...] >>> >>>> [ 13.643415] systemd[1]: Mounted Configuration File System. >>>> [ 17.526173] sata-dwc 4bffd1000.sata: sata_dwc_qc_prep_by_tag: dma_dwc_xfer_setup returns NULL >>>> [ 17.600124] sata-dwc 4bffd1000.sata: sata_dwc_qc_prep_by_tag: dma_dwc_xfer_setup returns NULL >>>> [ 17.662978] sata-dwc 4bffd1000.sata: sata_dwc_qc_prep_by_tag: dma_dwc_xfer_setup returns NULL >>> This log is weird. The sata_dwc_probe() function prints several things >>> (one using dev_notice()), for instance this: >>> >>> /* Read the ID and Version Registers */ >>> idr = in_le32(&hsdev->sata_dwc_regs->idr); >>> versionr = in_le32(&hsdev->sata_dwc_regs->versionr); >>> dev_notice(&ofdev->dev, "id %d, controller version %c.%c%c\n", >>> idr, ver[0], ver[1], ver[2]); >>> >>> The dw_dma_probe() function also prints a line: >>> >>> dev_info(chip->dev, "DesignWare DMA Controller, %d channels\n", >>> pdata->nr_channels); >>> >>> These messages are nowhere to be seen in your log, nor are numerous >>> others that really must appear before before sata_dwc_qc_prep_by_tag() >>> can be called. >>> >> It would be better to add 'ignore_loglevel' to the cmdline as well. OK, I've found something. The dma setup errors are benign, caused by the driver calling dmaengine_prep_slave_sg() even for non-dma operations. The real error is the lock recursion that's reported later. I wasn't seeing it since I was running a UP non-preempt kernel. With lock debugging enabled, I get the same error. This patch should fix it. ---8<--- >From 94c4769d2171ce66079fd486a45e09dd64db62c0 Mon Sep 17 00:00:00 2001 From: Mans Rullgard <mans@xxxxxxxxx> Date: Sat, 19 Dec 2015 15:26:23 +0000 Subject: [PATCH] ata: sata_dwc_460ex: remove incorrect locking This lock is already taken in ata_scsi_queuecmd() a few levels up the call stack so attempting to take it here is an error. Moreover, it is pointless in the first place since it only protects a single, atomic assignment. Signed-off-by: Mans Rullgard <mans@xxxxxxxxx> --- drivers/ata/sata_dwc_460ex.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/ata/sata_dwc_460ex.c b/drivers/ata/sata_dwc_460ex.c index 799df86..5696f39 100644 --- a/drivers/ata/sata_dwc_460ex.c +++ b/drivers/ata/sata_dwc_460ex.c @@ -1001,16 +1001,14 @@ static void sata_dwc_exec_command_by_tag(struct ata_port *ap, struct ata_taskfile *tf, u8 tag, u32 cmd_issued) { - unsigned long flags; struct sata_dwc_device_port *hsdevp = HSDEVP_FROM_AP(ap); struct sata_dwc_device *hsdev = HSDEV_FROM_AP(ap); dev_dbg(ap->dev, "%s cmd(0x%02x): %s tag=%d\n", __func__, tf->command, ata_get_cmd_descript(tf->command), tag); - spin_lock_irqsave(&ap->host->lock, flags); hsdevp->cmd_issued[tag] = cmd_issued; - spin_unlock_irqrestore(&ap->host->lock, flags); + /* * Clear SError before executing a new command. * sata_dwc_scr_write and read can not be used here. Clearing the PM -- 2.6.3 -- Måns Rullgård -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html