Fw: [PATCH] NVMe: Call nvme_pci_disable on error path of nvme_probe_work

[Kheria, Rashika]

________________________________________
From: Keith Busch <keith.busch@xxxxxxxxx>
Sent: Monday, November 14, 2016 7:47 PM
To: Kheria, Rashika
Cc: Christoph Hellwig; Kheria, Rashika; linux-nvme@xxxxxxxxxxxxxxxxxxx
Subject: Re: [PATCH] NVMe: Call nvme_pci_disable on error path of nvme_probe_work

On Mon, Nov 14, 2016 at 09:57:27AM +0100, Rashika Kheria wrote:
> Hi everyone,
>
> Could you please review the following patch? This solves a regression in
> stable 4.4.y tree.

I missed the "Don't unmap" back-port to 4.4.y. I'm not sure, but I think
we may have addressed that differently with something less risky if we
needed that behaviour on 4.4-stable. That's okay, though, this new patch
looks correct. The original was part of a series that fixes this in its
following commit, but it should have looked like this from the beginning.

Acked-by: Keith Busch <keith.busch@xxxxxxxxx>


> > On Tue, Nov 01, 2016 at 04:27:56PM +0100, Rashika Kheria wrote:
> > > Commit d5537e988eec ("NVMe: Don't unmap controller registers on reset"),
> > > introduced a regression in which it did not replace nvme_dev_unmap()
> > > with nvme_pci_disable() in the error path of nvme_probe_work().
> > >
> > > This led to the following NVMe driver crash on systems where the devices
> > > did not initialise in the first try.
> > >
> > > BUG: unable to handle kernel paging request at ffffc90006da001c
> > > IP: [<ffffffffa027b6bb>] nvme_dev_remove+0x5b/0xf0 [nvme]
> > > RIP: e030:[<ffffffffa027b6bb>]  [<ffffffffa027b6bb>]
> > > nvme_dev_remove+0x5b/0xf0 [nvme]
> > > RSP: e02b:ffff8806659c3cb8  EFLAGS: 00010286
> > > RAX: ffffc90006da0000 RBX: ffff88067cbc3000 RCX: 0000000000000006
> > > RDX: 0000000000000007 RSI: 0000000000000007 RDI: ffff8806864eda40
> > > RBP: ffff8806659c3cd8 R08: 0000000000000006 R09: 000000000000fffe
> > > R10: 0000000000000000 R11: 0000000000000000 R12: ffff88067e087000
> > > R13: ffffffffa0281d20 R14: ffff88067e087098 R15: ffff8806799d8598
> > > FS:  00007f880d5ba700(0000) GS:ffff8806864e0000(0000)
> > > knlGS:0000000000000000
> > > CS:  e033 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > CR2: ffffc90006da001c CR3: 0000000676a97000 CR4: 0000000000042660
> > > Call Trace:
> > > [<ffffffffa027b7ea>] nvme_remove+0x9a/0x140 [nvme]
> > > [<ffffffff813503ef>] pci_device_remove+0x3f/0xc0
> > > [<ffffffff81449869>] ? __pm_runtime_idle+0x89/0x90
> > > [<ffffffff8143ed4f>] __device_release_driver+0xaf/0x140
> > > [<ffffffff8143eec8>] device_release_driver+0x28/0x40
> > > [<ffffffff8143db66>] unbind_store+0x96/0xb0
> > > [<ffffffff8143d027>] drv_attr_store+0x27/0x30
> > > [<ffffffff8122e279>] sysfs_kf_write+0x39/0x40
> > > [<ffffffff8122d9e4>] kernfs_fop_write+0xe4/0x160
> > > [<ffffffff811b15df>] __vfs_write+0x2f/0x100
> > > [<ffffffff81003640>] ? syscall_slow_exit_work+0x140/0x180
> > > [<ffffffff81161db9>] ? vm_mmap_pgoff+0xb9/0xe0
> > > [<ffffffff810af981>] ? percpu_down_read+0x11/0x60
> > > [<ffffffff811b2bce>] vfs_write+0xbe/0x190
> > > [<ffffffff811b2d81>] SyS_write+0x51/0xb0
> > > [<ffffffff815b8aee>] entry_SYSCALL_64_fastpath+0x12/0x71
> > >
> > > Cc: stable@xxxxxxxxxxxxxxx # 4.4.y
> > > Cc: Jens Axboe <axboe@xxxxxx>
> > > Cc: Keith Busch <keith.busch@xxxxxxxxx>
> > > Cc: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxxxxxxx>
> > > Cc: linux-nvme@xxxxxxxxxxxxxxxxxxx
> > > Fixes: d5537e988eec ("NVMe: Don't unmap controller registers on reset")
> > > Signed-off-by: Rashika Kheria <rashika@xxxxxxxxx>
> > > ---
> > >   drivers/nvme/host/pci.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> > > index c851bc5..f5d1579 100644
> > > --- a/drivers/nvme/host/pci.c
> > > +++ b/drivers/nvme/host/pci.c
> > > @@ -3184,7 +3184,7 @@ static void nvme_probe_work(struct work_struct *work)
> > >           nvme_disable_queue(dev, 0);
> > >           nvme_dev_list_remove(dev);
> > >    unmap:
> > > - nvme_dev_unmap(dev);
> > > + nvme_pci_disable(dev);
> > >    out:
> > >           if (!work_busy(&dev->reset_work))
> > >                   nvme_dead_ctrl(dev);
> > > --
> > > 2.10.2
> > >
> > ---end quoted text---

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