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Date: Wed, 3 Apr 2019 09:02:36 +0100
From: John Garry <john.garry@...wei.com>
To: <rafael@...nel.org>, <gregkh@...uxfoundation.org>
CC: <linuxarm@...wei.com>, <chenxiang66@...ilicon.com>,
<robin.murphy@....com>, <geert@...ux-m68k.org>,
<linux-kernel@...r.kernel.org>, <iommu@...ts.linux-foundation.org>,
<linux-arm-kernel@...ts.infradead.org>, <robh@...nel.org>,
<hch@....de>
Subject: Re: [PATCH] driver core: Postpone DMA tear-down until after devres
release for probe failure
On 28/03/2019 10:08, John Garry wrote:
> In commit 376991db4b64 ("driver core: Postpone DMA tear-down until after
> devres release"), we changed the ordering of tearing down the device DMA
> ops and releasing all the device's resources; this was because the DMA ops
> should be maintained until we release the device's managed DMA memories.
>
Hi all,
A friendly reminder on this patch... I didn't see any update.
I thought that it had some importance.
Thanks,
John
> However, we have seen another crash on an arm64 system when a
> device driver probe fails:
>
> hisi_sas_v3_hw 0000:74:02.0: Adding to iommu group 2
> scsi host1: hisi_sas_v3_hw
> BUG: Bad page state in process swapper/0 pfn:313f5
> page:ffff7e0000c4fd40 count:1 mapcount:0
> mapping:0000000000000000 index:0x0
> flags: 0xfffe00000001000(reserved)
> raw: 0fffe00000001000 ffff7e0000c4fd48 ffff7e0000c4fd48
> 0000000000000000
> raw: 0000000000000000 0000000000000000 00000001ffffffff
> 0000000000000000
> page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
> bad because of flags: 0x1000(reserved)
> Modules linked in:
> CPU: 49 PID: 1 Comm: swapper/0 Not tainted
> 5.1.0-rc1-43081-g22d97fd-dirty #1433
> Hardware name: Huawei D06/D06, BIOS Hisilicon D06 UEFI
> RC0 - V1.12.01 01/29/2019
> Call trace:
> dump_backtrace+0x0/0x118
> show_stack+0x14/0x1c
> dump_stack+0xa4/0xc8
> bad_page+0xe4/0x13c
> free_pages_check_bad+0x4c/0xc0
> __free_pages_ok+0x30c/0x340
> __free_pages+0x30/0x44
> __dma_direct_free_pages+0x30/0x38
> dma_direct_free+0x24/0x38
> dma_free_attrs+0x9c/0xd8
> dmam_release+0x20/0x28
> release_nodes+0x17c/0x220
> devres_release_all+0x34/0x54
> really_probe+0xc4/0x2c8
> driver_probe_device+0x58/0xfc
> device_driver_attach+0x68/0x70
> __driver_attach+0x94/0xdc
> bus_for_each_dev+0x5c/0xb4
> driver_attach+0x20/0x28
> bus_add_driver+0x14c/0x200
> driver_register+0x6c/0x124
> __pci_register_driver+0x48/0x50
> sas_v3_pci_driver_init+0x20/0x28
> do_one_initcall+0x40/0x25c
> kernel_init_freeable+0x2b8/0x3c0
> kernel_init+0x10/0x100
> ret_from_fork+0x10/0x18
> Disabling lock debugging due to kernel taint
> BUG: Bad page state in process swapper/0 pfn:313f6
> page:ffff7e0000c4fd80 count:1 mapcount:0
> mapping:0000000000000000 index:0x0
> [ 89.322983] flags: 0xfffe00000001000(reserved)
> raw: 0fffe00000001000 ffff7e0000c4fd88 ffff7e0000c4fd88
> 0000000000000000
> raw: 0000000000000000 0000000000000000 00000001ffffffff
> 0000000000000000
>
> The crash occurs for the same reason.
>
> In this case, on the really_probe() failure path, we are still clearing
> the DMA ops prior to releasing the device's managed memories.
>
> This patch fixes this issue by reordering the DMA ops teardown and the
> call to devres_release_all() on the failure path.
>
> Reported-by: Xiang Chen <chenxiang66@...ilicon.com>
> Tested-by: Xiang Chen <chenxiang66@...ilicon.com>
> Signed-off-by: John Garry <john.garry@...wei.com>
> ---
>
> For convenience, here is the 2nd half of really_probe() now:
>
> atomic_inc(&probe_count);
> pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
> drv->bus->name, __func__, drv->name, dev_name(dev));
> WARN_ON(!list_empty(&dev->devres_head));
>
> re_probe:
> dev->driver = drv;
>
> /* If using pinctrl, bind pins now before probing */
> ret = pinctrl_bind_pins(dev);
> if (ret)
> goto pinctrl_bind_failed;
>
> if (dev->bus->dma_configure) {
> ret = dev->bus->dma_configure(dev);
> if (ret)
> goto probe_failed;
> }
>
> if (driver_sysfs_add(dev)) {
> printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
> __func__, dev_name(dev));
> goto probe_failed;
> }
>
> if (dev->pm_domain && dev->pm_domain->activate) {
> ret = dev->pm_domain->activate(dev);
> if (ret)
> goto probe_failed;
> }
>
> if (dev->bus->probe) {
> ret = dev->bus->probe(dev);
> if (ret)
> goto probe_failed;
> } else if (drv->probe) {
> ret = drv->probe(dev);
> if (ret)
> goto probe_failed;
> }
>
> if (test_remove) {
> test_remove = false;
>
> if (dev->bus->remove)
> dev->bus->remove(dev);
> else if (drv->remove)
> drv->remove(dev);
>
> devres_release_all(dev);
> driver_sysfs_remove(dev);
> dev->driver = NULL;
> dev_set_drvdata(dev, NULL);
> if (dev->pm_domain && dev->pm_domain->dismiss)
> dev->pm_domain->dismiss(dev);
> pm_runtime_reinit(dev);
>
> goto re_probe;
> }
>
> pinctrl_init_done(dev);
>
> if (dev->pm_domain && dev->pm_domain->sync)
> dev->pm_domain->sync(dev);
>
> driver_bound(dev);
> ret = 1;
> pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
> drv->bus->name, __func__, dev_name(dev), drv->name);
> goto done;
>
> probe_failed:
> if (dev->bus)
> blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
> BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
> pinctrl_bind_failed:
> device_links_no_driver(dev);
> devres_release_all(dev);
> arch_teardown_dma_ops(dev);
> driver_sysfs_remove(dev);
> dev->driver = NULL;
> dev_set_drvdata(dev, NULL);
> if (dev->pm_domain && dev->pm_domain->dismiss)
> dev->pm_domain->dismiss(dev);
> pm_runtime_reinit(dev);
> dev_pm_set_driver_flags(dev, 0);
>
> switch (ret) {
> case -EPROBE_DEFER:
> /* Driver requested deferred probing */
> dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
> driver_deferred_probe_add_trigger(dev, local_trigger_count);
> break;
> case -ENODEV:
> case -ENXIO:
> pr_debug("%s: probe of %s rejects match %d\n",
> drv->name, dev_name(dev), ret);
> break;
> default:
> /* driver matched but the probe failed */
> printk(KERN_WARNING
> "%s: probe of %s failed with error %d\n",
> drv->name, dev_name(dev), ret);
> }
> /*
> * Ignore errors returned by ->probe so that the next driver can try
> * its luck.
> */
> ret = 0;
> done:
> atomic_dec(&probe_count);
> wake_up(&probe_waitqueue);
> return ret;
> }
>
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index a823f469e53f..0df9b4461766 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -490,7 +490,7 @@ static int really_probe(struct device *dev, struct device_driver *drv)
> if (dev->bus->dma_configure) {
> ret = dev->bus->dma_configure(dev);
> if (ret)
> - goto dma_failed;
> + goto probe_failed;
> }
>
> if (driver_sysfs_add(dev)) {
> @@ -546,14 +546,13 @@ static int really_probe(struct device *dev, struct device_driver *drv)
> goto done;
>
> probe_failed:
> - arch_teardown_dma_ops(dev);
> -dma_failed:
> if (dev->bus)
> blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
> BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
> pinctrl_bind_failed:
> device_links_no_driver(dev);
> devres_release_all(dev);
> + arch_teardown_dma_ops(dev);
> driver_sysfs_remove(dev);
> dev->driver = NULL;
> dev_set_drvdata(dev, NULL);
>
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