Messages in this thread | | | Subject | Re: [PATCH] iommu/arm: Cleanup resources in case of probe error path | From | Robin Murphy <> | Date | Wed, 30 Jun 2021 15:01:56 +0100 |
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On 2021-06-30 14:48, Marek Szyprowski wrote: > On 30.06.2021 14:59, Will Deacon wrote: >> On Wed, Jun 30, 2021 at 02:48:15PM +0200, Marek Szyprowski wrote: >>> On 08.06.2021 18:45, Amey Narkhede wrote: >>>> If device registration fails, remove sysfs attribute >>>> and if setting bus callbacks fails, unregister the device >>>> and cleanup the sysfs attribute. >>>> >>>> Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com> >>> This patch landed in linux-next some time ago as commit 249c9dc6aa0d >>> ("iommu/arm: Cleanup resources in case of probe error path"). After >>> bisecting and some manual searching I finally found that it is >>> responsible for breaking s2idle on DragonBoard 410c. Here is the log >>> (captured with no_console_suspend): >>> >>> # time rtcwake -s10 -mmem >>> rtcwake: wakeup from "mem" using /dev/rtc0 at Thu Jan 1 00:02:13 1970 >>> PM: suspend entry (s2idle) >>> Filesystems sync: 0.002 seconds >>> Freezing user space processes ... (elapsed 0.006 seconds) done. >>> OOM killer disabled. >>> Freezing remaining freezable tasks ... (elapsed 0.004 seconds) done. >>> Unable to handle kernel NULL pointer dereference at virtual address >>> 0000000000000070 >>> Mem abort info: >>> ESR = 0x96000006 >>> EC = 0x25: DABT (current EL), IL = 32 bits >>> SET = 0, FnV = 0 >>> EA = 0, S1PTW = 0 >>> FSC = 0x06: level 2 translation fault >>> Data abort info: >>> ISV = 0, ISS = 0x00000006 >>> CM = 0, WnR = 0 >>> user pgtable: 4k pages, 48-bit VAs, pgdp=000000008ad08000 >>> [0000000000000070] pgd=0800000085c3c003, p4d=0800000085c3c003, >>> pud=0800000088dcf003, pmd=0000000000000000 >>> Internal error: Oops: 96000006 [#1] PREEMPT SMP >>> Modules linked in: bluetooth ecdh_generic ecc rfkill ipv6 ax88796b >>> venus_enc venus_dec videobuf2_dma_contig asix crct10dif_ce adv7511 >>> snd_soc_msm8916_analog qcom_spmi_temp_alarm rtc_pm8xxx qcom_pon >>> qcom_camss qcom_spmi_vadc videobuf2_dma_sg qcom_vadc_common msm >>> venus_core v4l2_fwnode v4l2_async snd_soc_msm8916_digital >>> videobuf2_memops snd_soc_lpass_apq8016 snd_soc_lpass_cpu v4l2_mem2mem >>> snd_soc_lpass_platform snd_soc_apq8016_sbc videobuf2_v4l2 >>> snd_soc_qcom_common qcom_rng videobuf2_common i2c_qcom_cci qnoc_msm8916 >>> videodev mc icc_smd_rpm mdt_loader socinfo display_connector rmtfs_mem >>> CPU: 1 PID: 1522 Comm: rtcwake Not tainted 5.13.0-next-20210629 #3592 >>> Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT) >>> pstate: 80000005 (Nzcv daif -PAN -UAO -TCO BTYPE=--) >>> pc : msm_runtime_suspend+0x1c/0x60 [msm] >>> lr : msm_pm_suspend+0x18/0x38 [msm] >>> ... >>> Call trace: >>> msm_runtime_suspend+0x1c/0x60 [msm] >>> msm_pm_suspend+0x18/0x38 [msm] >>> dpm_run_callback+0x84/0x378 >> I wonder if we're missing a pm_runtime_disable() call on the failure path? >> i.e. something like the diff below... > > I've checked and it doesn't fix anything.
What's happened previously? Has an IOMMU actually failed to probe, or is this a fiddly "code movement unveils latent bug elsewhere" kind of thing? There doesn't look to be much capable of going wrong in msm_runtime_suspend() itself, so is the DRM driver also in a broken half-probed state where it's left its pm_runtime_ops behind without its drvdata being valid?
Robin.
> >> Will >> >> --->8 >> >> diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c >> index 25ed444ff94d..ce8f354755d0 100644 >> --- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c >> +++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c >> @@ -836,14 +836,14 @@ static int qcom_iommu_device_probe(struct platform_device *pdev) >> ret = devm_of_platform_populate(dev); >> if (ret) { >> dev_err(dev, "Failed to populate iommu contexts\n"); >> - return ret; >> + goto err_pm_disable; >> } >> >> ret = iommu_device_sysfs_add(&qcom_iommu->iommu, dev, NULL, >> dev_name(dev)); >> if (ret) { >> dev_err(dev, "Failed to register iommu in sysfs\n"); >> - return ret; >> + goto err_pm_disable; >> } >> >> ret = iommu_device_register(&qcom_iommu->iommu, &qcom_iommu_ops, dev); >> @@ -869,6 +869,9 @@ static int qcom_iommu_device_probe(struct platform_device *pdev) >> >> err_sysfs_remove: >> iommu_device_sysfs_remove(&qcom_iommu->iommu); >> + >> +err_pm_disable: >> + pm_runtime_disable(dev); >> return ret; >> } >> > Best regards >
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