linux-stable.git/drivers/nvme/host, branch linux-4.9.y Linux kernel stable tree nvme: Fix IOC_PR_CLEAR and IOC_PR_RELEASE ioctls for nvme devices 2022-10-26T11:15:33+00:00 Michael Kelley mikelley@microsoft.com 2022-09-23T04:49:09+00:00 1463575044abc50619107e69762fdf24aeb4087d [ Upstream commit c292a337d0e45a292c301e3cd51c35aa0ae91e95 ] The IOC_PR_CLEAR and IOC_PR_RELEASE ioctls are non-functional on NVMe devices because the nvme_pr_clear() and nvme_pr_release() functions set the IEKEY field incorrectly. The IEKEY field should be set only when the key is zero (i.e, not specified). The current code does it backwards. Furthermore, the NVMe spec describes the persistent reservation "clear" function as an option on the reservation release command. The current implementation of nvme_pr_clear() erroneously uses the reservation register command. Fix these errors. Note that NVMe version 1.3 and later specify that setting the IEKEY field will return an error of Invalid Field in Command. The fix will set IEKEY when the key is zero, which is appropriate as these ioctls consider a zero key to be "unspecified", and the intention of the spec change is to require a valid key. Tested on a version 1.4 PCI NVMe device in an Azure VM. Fixes: 1673f1f08c88 ("nvme: move block_device_operations and ns/ctrl freeing to common code") Fixes: 1d277a637a71 ("NVMe: Add persistent reservation ops") Signed-off-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c292a337d0e45a292c301e3cd51c35aa0ae91e95 ]

The IOC_PR_CLEAR and IOC_PR_RELEASE ioctls are
non-functional on NVMe devices because the nvme_pr_clear()
and nvme_pr_release() functions set the IEKEY field incorrectly.
The IEKEY field should be set only when the key is zero (i.e,
not specified).  The current code does it backwards.

Furthermore, the NVMe spec describes the persistent
reservation "clear" function as an option on the reservation
release command. The current implementation of nvme_pr_clear()
erroneously uses the reservation register command.

Fix these errors. Note that NVMe version 1.3 and later specify
that setting the IEKEY field will return an error of Invalid
Field in Command.  The fix will set IEKEY when the key is zero,
which is appropriate as these ioctls consider a zero key to
be "unspecified", and the intention of the spec change is
to require a valid key.

Tested on a version 1.4 PCI NVMe device in an Azure VM.

Fixes: 1673f1f08c88 ("nvme: move block_device_operations and ns/ctrl freeing to common code")
Fixes: 1d277a637a71 ("NVMe: Add persistent reservation ops")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
nvme: add new line after variable declatation 2022-10-26T11:15:33+00:00 Chaitanya Kulkarni chaitanya.kulkarni@wdc.com 2021-03-01T02:06:11+00:00 2d1e103c6d817c324e0cbca81ed245821a132b87 [ Upstream commit f1c772d581843e3a14bbd62ef7e40b56fc307f27 ] Add a new line in functions nvme_pr_preempt(), nvme_pr_clear(), and nvme_pr_release() after variable declaration which follows the rest of the code in the nvme/host/core.c. No functional change(s) in this patch. Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Stable-dep-of: c292a337d0e4 ("nvme: Fix IOC_PR_CLEAR and IOC_PR_RELEASE ioctls for nvme devices") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit f1c772d581843e3a14bbd62ef7e40b56fc307f27 ]

Add a new line in functions nvme_pr_preempt(), nvme_pr_clear(), and
nvme_pr_release() after variable declaration which follows the rest of
the code in the nvme/host/core.c.

No functional change(s) in this patch.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Stable-dep-of: c292a337d0e4 ("nvme: Fix IOC_PR_CLEAR and IOC_PR_RELEASE ioctls for nvme devices")
Signed-off-by: Sasha Levin <sashal@kernel.org>
nvme-pci: fix a NULL pointer dereference in nvme_alloc_admin_tags 2022-06-14T14:52:29+00:00 Smith, Kyle Miller (Nimble Kernel) kyles@hpe.com 2022-04-22T14:40:32+00:00 8321b17789f614414206af07e17ce4751c95dc76 [ Upstream commit da42761181627e9bdc37d18368b827948a583929 ] In nvme_alloc_admin_tags, the admin_q can be set to an error (typically -ENOMEM) if the blk_mq_init_queue call fails to set up the queue, which is checked immediately after the call. However, when we return the error message up the stack, to nvme_reset_work the error takes us to nvme_remove_dead_ctrl() nvme_dev_disable() nvme_suspend_queue(&dev->queues[0]). Here, we only check that the admin_q is non-NULL, rather than not an error or NULL, and begin quiescing a queue that never existed, leading to bad / NULL pointer dereference. Signed-off-by: Kyle Smith <kyles@hpe.com> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit da42761181627e9bdc37d18368b827948a583929 ]

In nvme_alloc_admin_tags, the admin_q can be set to an error (typically
-ENOMEM) if the blk_mq_init_queue call fails to set up the queue, which
is checked immediately after the call. However, when we return the error
message up the stack, to nvme_reset_work the error takes us to
nvme_remove_dead_ctrl()
  nvme_dev_disable()
   nvme_suspend_queue(&dev->queues[0]).

Here, we only check that the admin_q is non-NULL, rather than not
an error or NULL, and begin quiescing a queue that never existed, leading
to bad / NULL pointer dereference.

Signed-off-by: Kyle Smith <kyles@hpe.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
nvme-pci: Fix an error handling path in 'nvme_probe()' 2021-09-22T09:42:57+00:00 Christophe JAILLET christophe.jaillet@wanadoo.fr 2017-07-16T08:39:03+00:00 da6fe93816dac3521d5bb8309d83707f042d4b5c commit b00c9b7aa06786fc5469783965ff3e2a705a1dec upstream. Release resources in the correct order in order not to miss a 'put_device()' if 'nvme_dev_map()' fails. Fixes: b00a726a9fd8 ("NVMe: Don't unmap controller registers on reset") Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit b00c9b7aa06786fc5469783965ff3e2a705a1dec upstream.

Release resources in the correct order in order not to miss a
'put_device()' if 'nvme_dev_map()' fails.

Fixes: b00a726a9fd8 ("NVMe: Don't unmap controller registers on reset")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nvme: retain split access workaround for capability reads 2020-01-29T09:24:33+00:00 Ard Biesheuvel ard.biesheuvel@linaro.org 2019-10-03T11:57:29+00:00 9ca487b7600fa0a0afc046a254215c96c5dae3ce [ Upstream commit 3a8ecc935efabdad106b5e06d07b150c394b4465 ] Commit 7fd8930f26be4 "nvme: add a common helper to read Identify Controller data" has re-introduced an issue that we have attempted to work around in the past, in commit a310acd7a7ea ("NVMe: use split lo_hi_{read,write}q"). The problem is that some PCIe NVMe controllers do not implement 64-bit outbound accesses correctly, which is why the commit above switched to using lo_hi_[read|write]q for all 64-bit BAR accesses occuring in the code. In the mean time, the NVMe subsystem has been refactored, and now calls into the PCIe support layer for NVMe via a .reg_read64() method, which fails to use lo_hi_readq(), and thus reintroduces the problem that the workaround above aimed to address. Given that, at the moment, .reg_read64() is only used to read the capability register [which is known to tolerate split reads], let's switch .reg_read64() to lo_hi_readq() as well. This fixes a boot issue on some ARM boxes with NVMe behind a Synopsys DesignWare PCIe host controller. Fixes: 7fd8930f26be4 ("nvme: add a common helper to read Identify Controller data") Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 3a8ecc935efabdad106b5e06d07b150c394b4465 ]

Commit 7fd8930f26be4

  "nvme: add a common helper to read Identify Controller data"

has re-introduced an issue that we have attempted to work around in the
past, in commit a310acd7a7ea ("NVMe: use split lo_hi_{read,write}q").

The problem is that some PCIe NVMe controllers do not implement 64-bit
outbound accesses correctly, which is why the commit above switched
to using lo_hi_[read|write]q for all 64-bit BAR accesses occuring in
the code.

In the mean time, the NVMe subsystem has been refactored, and now calls
into the PCIe support layer for NVMe via a .reg_read64() method, which
fails to use lo_hi_readq(), and thus reintroduces the problem that the
workaround above aimed to address.

Given that, at the moment, .reg_read64() is only used to read the
capability register [which is known to tolerate split reads], let's
switch .reg_read64() to lo_hi_readq() as well.

This fixes a boot issue on some ARM boxes with NVMe behind a Synopsys
DesignWare PCIe host controller.

Fixes: 7fd8930f26be4 ("nvme: add a common helper to read Identify Controller data")
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Sasha Levin <sashal@kernel.org>
nvme: host: core: fix precedence of ternary operator 2019-12-21T09:42:21+00:00 Ivan Bornyakov brnkv.i1@gmail.com 2018-05-23T14:56:11+00:00 c39c0be92c9d7c7aec963b99f95c1b72b9deafc6 commit e9a9853c23c13a37546397b61b270999fd0fb759 upstream. Ternary operator have lower precedence then bitwise or, so 'cdw10' was calculated wrong. Signed-off-by: Ivan Bornyakov <brnkv.i1@gmail.com> Reviewed-by: Max Gurtovoy <maxg@mellanox.com> Signed-off-by: Keith Busch <keith.busch@intel.com> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e9a9853c23c13a37546397b61b270999fd0fb759 upstream.

Ternary operator have lower precedence then bitwise or, so 'cdw10' was
calculated wrong.

Signed-off-by: Ivan Bornyakov <brnkv.i1@gmail.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nvme: Fix u32 overflow in the number of namespace list calculation 2019-07-10T07:55:32+00:00 Jaesoo Lee jalee@purestorage.com 2019-06-03T23:42:28+00:00 0e6a89a37a671a8dbaac9f8012a59e44e879e292 [ Upstream commit c8e8c77b3bdbade6e26e8e76595f141ede12b692 ] The Number of Namespaces (nn) field in the identify controller data structure is defined as u32 and the maximum allowed value in NVMe specification is 0xFFFFFFFEUL. This change fixes the possible overflow of the DIV_ROUND_UP() operation used in nvme_scan_ns_list() by casting the nn to u64. Signed-off-by: Jaesoo Lee <jalee@purestorage.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c8e8c77b3bdbade6e26e8e76595f141ede12b692 ]

The Number of Namespaces (nn) field in the identify controller data structure is
defined as u32 and the maximum allowed value in NVMe specification is
0xFFFFFFFEUL. This change fixes the possible overflow of the DIV_ROUND_UP()
operation used in nvme_scan_ns_list() by casting the nn to u64.

Signed-off-by: Jaesoo Lee <jalee@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Sasha Levin <sashal@kernel.org>
nvme-pci: fix CMB sysfs file removal in reset path 2018-11-10T15:42:46+00:00 Max Gurtovoy maxg@mellanox.com 2017-07-29T22:45:08+00:00 3cd731e952df562312ea1a7c459807382acb9f8b [ Upstream commit 1c78f7735b2bdd0afbe5d14c5c8b6d8d381b6f13 ] Currently we create the sysfs entry even if we fail mapping it. In that case, the unmapping will not remove the sysfs created file. There is no good reason to create a sysfs entry for a non working CMB and show his characteristics. Fixes: f63572dff ("nvme: unmap CMB and remove sysfs file in reset path") Signed-off-by: Max Gurtovoy <maxg@mellanox.com> Reviewed-by: Stephen Bates <sbates@raithlin.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 1c78f7735b2bdd0afbe5d14c5c8b6d8d381b6f13 ]

Currently we create the sysfs entry even if we fail mapping
it. In that case, the unmapping will not remove the sysfs created
file. There is no good reason to create a sysfs entry for a non
working CMB and show his characteristics.

Fixes: f63572dff ("nvme: unmap CMB and remove sysfs file in reset path")
Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Stephen Bates <sbates@raithlin.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
nvme-pci: Remap CMB SQ entries on every controller reset 2018-07-17T09:37:54+00:00 Keith Busch keith.busch@intel.com 2018-02-13T12:44:44+00:00 062c4965a1e66361f3840fe8234871500af3549e commit 815c6704bf9f1c59f3a6be380a4032b9c57b12f1 upstream. The controller memory buffer is remapped into a kernel address on each reset, but the driver was setting the submission queue base address only on the very first queue creation. The remapped address is likely to change after a reset, so accessing the old address will hit a kernel bug. This patch fixes that by setting the queue's CMB base address each time the queue is created. Fixes: f63572dff1421 ("nvme: unmap CMB and remove sysfs file in reset path") Reported-by: Christian Black <christian.d.black@intel.com> Cc: Jon Derrick <jonathan.derrick@intel.com> Cc: <stable@vger.kernel.org> # 4.9+ Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Scott Bauer <scott.bauer@intel.com> Reviewed-by: Jon Derrick <jonathan.derrick@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 815c6704bf9f1c59f3a6be380a4032b9c57b12f1 upstream.

The controller memory buffer is remapped into a kernel address on each
reset, but the driver was setting the submission queue base address
only on the very first queue creation. The remapped address is likely to
change after a reset, so accessing the old address will hit a kernel bug.

This patch fixes that by setting the queue's CMB base address each time
the queue is created.

Fixes: f63572dff1421 ("nvme: unmap CMB and remove sysfs file in reset path")
Reported-by: Christian Black <christian.d.black@intel.com>
Cc: Jon Derrick <jonathan.derrick@intel.com>
Cc: <stable@vger.kernel.org> # 4.9+
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Scott Bauer <scott.bauer@intel.com>
Reviewed-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nvme: validate admin queue before unquiesce 2018-07-17T09:37:51+00:00 Scott Bauer scott.bauer@intel.com 2017-07-25T16:27:06+00:00 93e54f40c89336adc28b4125529bb75d4b565a70 commit 7dd1ab163c17e11473a65b11f7e748db30618ebb upstream. With a misbehaving controller it's possible we'll never enter the live state and create an admin queue. When we fail out of reset work it's possible we failed out early enough without setting up the admin queue. We tear down queues after a failed reset, but needed to do some more sanitization. Fixes 443bd90f2cca: "nvme: host: unquiesce queue in nvme_kill_queues()" [ 189.650995] nvme nvme1: pci function 0000:0b:00.0 [ 317.680055] nvme nvme0: Device not ready; aborting reset [ 317.680183] nvme nvme0: Removing after probe failure status: -19 [ 317.681258] kasan: GPF could be caused by NULL-ptr deref or user memory access [ 317.681397] general protection fault: 0000 [#1] SMP KASAN [ 317.682984] CPU: 3 PID: 477 Comm: kworker/3:2 Not tainted 4.13.0-rc1+ #5 [ 317.683112] Hardware name: Gigabyte Technology Co., Ltd. Z170X-UD5/Z170X-UD5-CF, BIOS F5 03/07/2016 [ 317.683284] Workqueue: events nvme_remove_dead_ctrl_work [nvme] [ 317.683398] task: ffff8803b0990000 task.stack: ffff8803c2ef0000 [ 317.683516] RIP: 0010:blk_mq_unquiesce_queue+0x2b/0xa0 [ 317.683614] RSP: 0018:ffff8803c2ef7d40 EFLAGS: 00010282 [ 317.683716] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff1006fbdcde3 [ 317.683847] RDX: 0000000000000038 RSI: 1ffff1006f5a9245 RDI: 0000000000000000 [ 317.683978] RBP: ffff8803c2ef7d58 R08: 1ffff1007bcdc974 R09: 0000000000000000 [ 317.684108] R10: 1ffff1007bcdc975 R11: 0000000000000000 R12: 00000000000001c0 [ 317.684239] R13: ffff88037ad49228 R14: ffff88037ad492d0 R15: ffff88037ad492e0 [ 317.684371] FS: 0000000000000000(0000) GS:ffff8803de6c0000(0000) knlGS:0000000000000000 [ 317.684519] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 317.684627] CR2: 0000002d1860c000 CR3: 000000045b40d000 CR4: 00000000003406e0 [ 317.684758] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 317.684888] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 317.685018] Call Trace: [ 317.685084] nvme_kill_queues+0x4d/0x170 [nvme_core] [ 317.685185] nvme_remove_dead_ctrl_work+0x3a/0x90 [nvme] [ 317.685289] process_one_work+0x771/0x1170 [ 317.685372] worker_thread+0xde/0x11e0 [ 317.685452] ? pci_mmcfg_check_reserved+0x110/0x110 [ 317.685550] kthread+0x2d3/0x3d0 [ 317.685617] ? process_one_work+0x1170/0x1170 [ 317.685704] ? kthread_create_on_node+0xc0/0xc0 [ 317.685785] ret_from_fork+0x25/0x30 [ 317.685798] Code: 0f 1f 44 00 00 55 48 b8 00 00 00 00 00 fc ff df 48 89 e5 41 54 4c 8d a7 c0 01 00 00 53 48 89 fb 4c 89 e2 48 c1 ea 03 48 83 ec 08 <80> 3c 02 00 75 50 48 8b bb c0 01 00 00 e8 33 8a f9 00 0f ba b3 [ 317.685872] RIP: blk_mq_unquiesce_queue+0x2b/0xa0 RSP: ffff8803c2ef7d40 [ 317.685908] ---[ end trace a3f8704150b1e8b4 ]--- Signed-off-by: Scott Bauer <scott.bauer@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de> [ adapted for 4.9: added check around blk_mq_start_hw_queues() call instead of upstream blk_mq_unquiesce_queue() ] Fixes: 4aae4388165a2611fa42 ("nvme: fix hang in remove path") Signed-off-by: Simon Veith <sveith@amazon.de> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Amit Shah <aams@amazon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 7dd1ab163c17e11473a65b11f7e748db30618ebb upstream.

With a misbehaving controller it's possible we'll never
enter the live state and create an admin queue. When we
fail out of reset work it's possible we failed out early
enough without setting up the admin queue. We tear down
queues after a failed reset, but needed to do some more
sanitization.

Fixes 443bd90f2cca: "nvme: host: unquiesce queue in nvme_kill_queues()"

[  189.650995] nvme nvme1: pci function 0000:0b:00.0
[  317.680055] nvme nvme0: Device not ready; aborting reset
[  317.680183] nvme nvme0: Removing after probe failure status: -19
[  317.681258] kasan: GPF could be caused by NULL-ptr deref or user memory access
[  317.681397] general protection fault: 0000 [#1] SMP KASAN
[  317.682984] CPU: 3 PID: 477 Comm: kworker/3:2 Not tainted 4.13.0-rc1+ #5
[  317.683112] Hardware name: Gigabyte Technology Co., Ltd. Z170X-UD5/Z170X-UD5-CF, BIOS F5 03/07/2016
[  317.683284] Workqueue: events nvme_remove_dead_ctrl_work [nvme]
[  317.683398] task: ffff8803b0990000 task.stack: ffff8803c2ef0000
[  317.683516] RIP: 0010:blk_mq_unquiesce_queue+0x2b/0xa0
[  317.683614] RSP: 0018:ffff8803c2ef7d40 EFLAGS: 00010282
[  317.683716] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff1006fbdcde3
[  317.683847] RDX: 0000000000000038 RSI: 1ffff1006f5a9245 RDI: 0000000000000000
[  317.683978] RBP: ffff8803c2ef7d58 R08: 1ffff1007bcdc974 R09: 0000000000000000
[  317.684108] R10: 1ffff1007bcdc975 R11: 0000000000000000 R12: 00000000000001c0
[  317.684239] R13: ffff88037ad49228 R14: ffff88037ad492d0 R15: ffff88037ad492e0
[  317.684371] FS:  0000000000000000(0000) GS:ffff8803de6c0000(0000) knlGS:0000000000000000
[  317.684519] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  317.684627] CR2: 0000002d1860c000 CR3: 000000045b40d000 CR4: 00000000003406e0
[  317.684758] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  317.684888] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  317.685018] Call Trace:
[  317.685084]  nvme_kill_queues+0x4d/0x170 [nvme_core]
[  317.685185]  nvme_remove_dead_ctrl_work+0x3a/0x90 [nvme]
[  317.685289]  process_one_work+0x771/0x1170
[  317.685372]  worker_thread+0xde/0x11e0
[  317.685452]  ? pci_mmcfg_check_reserved+0x110/0x110
[  317.685550]  kthread+0x2d3/0x3d0
[  317.685617]  ? process_one_work+0x1170/0x1170
[  317.685704]  ? kthread_create_on_node+0xc0/0xc0
[  317.685785]  ret_from_fork+0x25/0x30
[  317.685798] Code: 0f 1f 44 00 00 55 48 b8 00 00 00 00 00 fc ff df 48 89 e5 41 54 4c 8d a7 c0 01 00 00 53 48 89 fb 4c 89 e2 48 c1 ea 03 48 83 ec 08 <80> 3c 02 00 75 50 48 8b bb c0 01 00 00 e8 33 8a f9 00 0f ba b3
[  317.685872] RIP: blk_mq_unquiesce_queue+0x2b/0xa0 RSP: ffff8803c2ef7d40
[  317.685908] ---[ end trace a3f8704150b1e8b4 ]---

Signed-off-by: Scott Bauer <scott.bauer@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
[ adapted for 4.9: added check around blk_mq_start_hw_queues() call
  instead of upstream blk_mq_unquiesce_queue() ]
Fixes: 4aae4388165a2611fa42 ("nvme: fix hang in remove path")
Signed-off-by: Simon Veith <sveith@amazon.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Amit Shah <aams@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>