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nvme-pci: fix multiple ctrl removal scheduling

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Commit c5f6ce97c1 tries to address multiple resets but fails as
work_busy doesn't involve any synchronization and can fail.  This is
reproducible easily as can be seen by WARNING below which is triggered
with line:

WARN_ON(dev->ctrl.state == NVME_CTRL_RESETTING)

Allowing multiple resets can result in multiple controller removal as
well if different conditions inside nvme_reset_work fail and which
might deadlock on device_release_driver.

[  480.327007] WARNING: CPU: 3 PID: 150 at drivers/nvme/host/pci.c:1900 nvme_reset_work+0x36c/0xec0
[  480.327008] Modules linked in: rfcomm fuse nf_conntrack_netbios_ns nf_conntrack_broadcast...
[  480.327044]  btusb videobuf2_core ghash_clmulni_intel snd_hwdep cfg80211 acer_wmi hci_uart..
[  480.327065] CPU: 3 PID: 150 Comm: kworker/u16:2 Not tainted 4.12.0-rc1+ #13
[  480.327065] Hardware name: Acer Predator G9-591/Mustang_SLS, BIOS V1.10 03/03/2016
[  480.327066] Workqueue: nvme nvme_reset_work
[  480.327067] task: ffff880498ad8000 task.stack: ffffc90002218000
[  480.327068] RIP: 0010:nvme_reset_work+0x36c/0xec0
[  480.327069] RSP: 0018:ffffc9000221bdb8 EFLAGS: 00010246
[  480.327070] RAX: 0000000000460000 RBX: ffff880498a98128 RCX: dead000000000200
[  480.327070] RDX: 0000000000000001 RSI: ffff8804b1028020 RDI: ffff880498a98128
[  480.327071] RBP: ffffc9000221be50 R08: 0000000000000000 R09: 0000000000000000
[  480.327071] R10: ffffc90001963ce8 R11: 000000000000020d R12: ffff880498a98000
[  480.327072] R13: ffff880498a53500 R14: ffff880498a98130 R15: ffff880498a98128
[  480.327072] FS:  0000000000000000(0000) GS:ffff8804c1cc0000(0000) knlGS:0000000000000000
[  480.327073] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  480.327074] CR2: 00007ffcf3c37f78 CR3: 0000000001e09000 CR4: 00000000003406e0
[  480.327074] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  480.327075] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  480.327075] Call Trace:
[  480.327079]  ? __switch_to+0x227/0x400
[  480.327081]  process_one_work+0x18c/0x3a0
[  480.327082]  worker_thread+0x4e/0x3b0
[  480.327084]  kthread+0x109/0x140
[  480.327085]  ? process_one_work+0x3a0/0x3a0
[  480.327087]  ? kthread_park+0x60/0x60
[  480.327102]  ret_from_fork+0x2c/0x40
[  480.327103] Code: e8 5a dc ff ff 85 c0 41 89 c1 0f.....

This patch addresses the problem by using state of controller to
decide whether reset should be queued or not as state change is
synchronizated using controller spinlock.  Also cancel_work_sync is
used to make sure remove cancels the reset_work and waits for it to
finish.  This patch also changes return value from -ENODEV to more
appropriate -EBUSY if nvme_reset fails to change state.

Fixes: c5f6ce97c1 ("nvme: don't schedule multiple resets")
Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Rakesh Pandit 2017-06-05 14:43:11 +03:00 committed by Christoph Hellwig
parent 82654b6b8e
commit 82b057caef
1 changed files with 6 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/nvme/host/pci.c
View File

@ -1367,7 +1367,7 @@ static bool nvme_should_reset(struct nvme_dev *dev, u32 csts)
bool nssro = dev->subsystem && (csts & NVME_CSTS_NSSRO);
/* If there is a reset ongoing, we shouldn't reset again. */
if (work_busy(&dev->reset_work))
if (dev->ctrl.state == NVME_CTRL_RESETTING)
return false;
/* We shouldn't reset unless the controller is on fatal error state
@ -1903,7 +1903,7 @@ static void nvme_reset_work(struct work_struct *work)
bool was_suspend = !!(dev->ctrl.ctrl_config & NVME_CC_SHN_NORMAL);
int result = -ENODEV;
if (WARN_ON(dev->ctrl.state == NVME_CTRL_RESETTING))
if (WARN_ON(dev->ctrl.state != NVME_CTRL_RESETTING))
goto out;
/*
@ -1913,9 +1913,6 @@ static void nvme_reset_work(struct work_struct *work)
if (dev->ctrl.ctrl_config & NVME_CC_ENABLE)
nvme_dev_disable(dev, false);
if (!nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_RESETTING))
goto out;
result = nvme_pci_enable(dev);
if (result)
goto out;
@ -2009,8 +2006,8 @@ static int nvme_reset(struct nvme_dev *dev)
{
if (!dev->ctrl.admin_q || blk_queue_dying(dev->ctrl.admin_q))
return -ENODEV;
if (work_busy(&dev->reset_work))
return -ENODEV;
if (!nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_RESETTING))
return -EBUSY;
if (!queue_work(nvme_workq, &dev->reset_work))
return -EBUSY;
return 0;
@ -2136,6 +2133,7 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
if (result)
goto release_pools;
nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_RESETTING);
dev_info(dev->ctrl.device, "pci function %s\n", dev_name(&pdev->dev));
queue_work(nvme_workq, &dev->reset_work);
@ -2179,6 +2177,7 @@ static void nvme_remove(struct pci_dev *pdev)
nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DELETING);
cancel_work_sync(&dev->reset_work);
pci_set_drvdata(pdev, NULL);
if (!pci_device_is_present(pdev)) {