linux-stable.git/drivers/nvme, branch v4.14.78 Linux kernel stable tree nvme_fc: fix ctrl create failures racing with workq items 2018-10-13T07:27:28+00:00 James Smart jsmart2021@gmail.com 2018-03-13T16:48:07+00:00 0f6e2f4e06be4da35c1b9e52d638218bafa91e25 commit cf25809bec2c7df4b45df5b2196845d9a4a3c89b upstream. If there are errors during initial controller create, the transport will teardown the partially initialized controller struct and free the ctlr memory. Trouble is - most of those errors can occur due to asynchronous events happening such io timeouts and subsystem connectivity failures. Those failures invoke async workq items to reset the controller and attempt reconnect. Those may be in progress as the main thread frees the ctrl memory, resulting in NULL ptr oops. Prevent this from happening by having the main ctrl failure thread changing state to DELETING followed by synchronously cancelling any pending queued work item. The change of state will prevent the scheduling of resets or reconnect events. Signed-off-by: James Smart <james.smart@broadcom.com> Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit cf25809bec2c7df4b45df5b2196845d9a4a3c89b upstream.

If there are errors during initial controller create, the transport
will teardown the partially initialized controller struct and free
the ctlr memory.  Trouble is - most of those errors can occur due
to asynchronous events happening such io timeouts and subsystem
connectivity failures. Those failures invoke async workq items to
reset the controller and attempt reconnect.  Those may be in progress
as the main thread frees the ctrl memory, resulting in NULL ptr oops.

Prevent this from happening by having the main ctrl failure thread
changing state to DELETING followed by synchronously cancelling any
pending queued work item. The change of state will prevent the
scheduling of resets or reconnect events.

Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nvmet-rdma: fix possible bogus dereference under heavy load 2018-10-10T06:54:24+00:00 Sagi Grimberg sagi@grimberg.me 2018-09-03T10:47:07+00:00 f36f3ebdf1e1a211c3be521e187d69a94b30db77 [ Upstream commit 8407879c4e0d7731f6e7e905893cecf61a7762c7 ] Currently we always repost the recv buffer before we send a response capsule back to the host. Since ordering is not guaranteed for send and recv completions, it is posible that we will receive a new request from the host before we got a send completion for the response capsule. Today, we pre-allocate 2x rsps the length of the queue, but in reality, under heavy load there is nothing that is really preventing the gap to expand until we exhaust all our rsps. To fix this, if we don't have any pre-allocated rsps left, we dynamically allocate a rsp and make sure to free it when we are done. If under memory pressure we fail to allocate a rsp, we silently drop the command and wait for the host to retry. Reported-by: Steve Wise <swise@opengridcomputing.com> Tested-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> [hch: dropped a superflous assignment] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 8407879c4e0d7731f6e7e905893cecf61a7762c7 ]

Currently we always repost the recv buffer before we send a response
capsule back to the host. Since ordering is not guaranteed for send
and recv completions, it is posible that we will receive a new request
from the host before we got a send completion for the response capsule.

Today, we pre-allocate 2x rsps the length of the queue, but in reality,
under heavy load there is nothing that is really preventing the gap to
expand until we exhaust all our rsps.

To fix this, if we don't have any pre-allocated rsps left, we dynamically
allocate a rsp and make sure to free it when we are done. If under memory
pressure we fail to allocate a rsp, we silently drop the command and
wait for the host to retry.

Reported-by: Steve Wise <swise@opengridcomputing.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
[hch: dropped a superflous assignment]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nvme-fcloop: Fix dropped LS's to removed target port 2018-10-04T00:00:59+00:00 James Smart jsmart2021@gmail.com 2018-08-09T23:00:14+00:00 d11237bdcf9570edc0c562d93df219a4a8a4c9f0 [ Upstream commit afd299ca996929f4f98ac20da0044c0cdc124879 ] When a targetport is removed from the config, fcloop will avoid calling the LS done() routine thinking the targetport is gone. This leaves the initiator reset/reconnect hanging as it waits for a status on the Create_Association LS for the reconnect. Change the filter in the LS callback path. If tport null (set when failed validation before "sending to remote port"), be sure to call done. This was the main bug. But, continue the logic that only calls done if tport was set but there is no remoteport (e.g. case where remoteport has been removed, thus host doesn't expect a completion). Signed-off-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit afd299ca996929f4f98ac20da0044c0cdc124879 ]

When a targetport is removed from the config, fcloop will avoid calling
the LS done() routine thinking the targetport is gone. This leaves the
initiator reset/reconnect hanging as it waits for a status on the
Create_Association LS for the reconnect.

Change the filter in the LS callback path. If tport null (set when
failed validation before "sending to remote port"), be sure to call
done. This was the main bug. But, continue the logic that only calls
done if tport was set but there is no remoteport (e.g. case where
remoteport has been removed, thus host doesn't expect a completion).

Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nvme-rdma: unquiesce queues when deleting the controller 2018-09-26T06:38:02+00:00 Sagi Grimberg sagi@grimberg.me 2018-07-09T09:49:05+00:00 3cb3868f98f53468160eb732d30ef29aaf046ae3 [ Upstream commit 90140624e8face94207003ac9a9d2a329b309d68 ] If the controller is going away, we need to unquiesce the IO queues so that all pending request can fail gracefully before moving forward with controller deletion. Do that before we destroy the IO queues so blk_cleanup_queue won't block in freeze. Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 90140624e8face94207003ac9a9d2a329b309d68 ]

If the controller is going away, we need to unquiesce the IO queues so
that all pending request can fail gracefully before moving forward with
controller deletion. Do that before we destroy the IO queues so
blk_cleanup_queue won't block in freeze.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nvme-pci: add a memory barrier to nvme_dbbuf_update_and_check_event 2018-09-05T07:26:36+00:00 Michal Wnukowski wnukowski@google.com 2018-08-15T22:51:57+00:00 0c9bed3698891c256b8a83d0c5001286bb87699b commit f1ed3df20d2d223e0852cc4ac1f19bba869a7e3c upstream. In many architectures loads may be reordered with older stores to different locations. In the nvme driver the following two operations could be reordered: - Write shadow doorbell (dbbuf_db) into memory. - Read EventIdx (dbbuf_ei) from memory. This can result in a potential race condition between driver and VM host processing requests (if given virtual NVMe controller has a support for shadow doorbell). If that occurs, then the NVMe controller may decide to wait for MMIO doorbell from guest operating system, and guest driver may decide not to issue MMIO doorbell on any of subsequent commands. This issue is purely timing-dependent one, so there is no easy way to reproduce it. Currently the easiest known approach is to run "Oracle IO Numbers" (orion) that is shipped with Oracle DB: orion -run advanced -num_large 0 -size_small 8 -type rand -simulate \ concat -write 40 -duration 120 -matrix row -testname nvme_test Where nvme_test is a .lun file that contains a list of NVMe block devices to run test against. Limiting number of vCPUs assigned to given VM instance seems to increase chances for this bug to occur. On test environment with VM that got 4 NVMe drives and 1 vCPU assigned the virtual NVMe controller hang could be observed within 10-20 minutes. That correspond to about 400-500k IO operations processed (or about 100GB of IO read/writes). Orion tool was used as a validation and set to run in a loop for 36 hours (equivalent of pushing 550M IO operations). No issues were observed. That suggest that the patch fixes the issue. Fixes: f9f38e33389c ("nvme: improve performance for virtual NVMe devices") Signed-off-by: Michal Wnukowski <wnukowski@google.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> [hch: updated changelog and comment a bit] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit f1ed3df20d2d223e0852cc4ac1f19bba869a7e3c upstream.

In many architectures loads may be reordered with older stores to
different locations.  In the nvme driver the following two operations
could be reordered:

 - Write shadow doorbell (dbbuf_db) into memory.
 - Read EventIdx (dbbuf_ei) from memory.

This can result in a potential race condition between driver and VM host
processing requests (if given virtual NVMe controller has a support for
shadow doorbell).  If that occurs, then the NVMe controller may decide to
wait for MMIO doorbell from guest operating system, and guest driver may
decide not to issue MMIO doorbell on any of subsequent commands.

This issue is purely timing-dependent one, so there is no easy way to
reproduce it. Currently the easiest known approach is to run "Oracle IO
Numbers" (orion) that is shipped with Oracle DB:

orion -run advanced -num_large 0 -size_small 8 -type rand -simulate \
	concat -write 40 -duration 120 -matrix row -testname nvme_test

Where nvme_test is a .lun file that contains a list of NVMe block
devices to run test against. Limiting number of vCPUs assigned to given
VM instance seems to increase chances for this bug to occur. On test
environment with VM that got 4 NVMe drives and 1 vCPU assigned the
virtual NVMe controller hang could be observed within 10-20 minutes.
That correspond to about 400-500k IO operations processed (or about
100GB of IO read/writes).

Orion tool was used as a validation and set to run in a loop for 36
hours (equivalent of pushing 550M IO operations). No issues were
observed. That suggest that the patch fixes the issue.

Fixes: f9f38e33389c ("nvme: improve performance for virtual NVMe devices")
Signed-off-by: Michal Wnukowski <wnukowski@google.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
[hch: updated changelog and comment a bit]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nvme: fix handling of metadata_len for NVME_IOCTL_IO_CMD 2018-08-24T11:09:21+00:00 Roland Dreier roland@purestorage.com 2018-07-20T03:07:59+00:00 7a12f4ed07a5f7b49c7d4f86ea67f65ec953cc40 [ Upstream commit 9b382768135ee3ff282f828c906574a8478e036b ] The old code in nvme_user_cmd() passed the userspace virtual address from nvme_passthru_cmd.metadata as the length of the metadata buffer as well as the address to nvme_submit_user_cmd(). Fixes: 63263d60 ("nvme: Use metadata for passthrough commands") Signed-off-by: Roland Dreier <roland@purestorage.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 9b382768135ee3ff282f828c906574a8478e036b ]

The old code in nvme_user_cmd() passed the userspace virtual address
from nvme_passthru_cmd.metadata as the length of the metadata buffer
as well as the address to nvme_submit_user_cmd().

Fixes: 63263d60 ("nvme: Use metadata for passthrough commands")
Signed-off-by: Roland Dreier <roland@purestorage.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nvmet: reset keep alive timer in controller enable 2018-08-24T11:09:02+00:00 Max Gurtuvoy maxg@mellanox.com 2018-06-19T12:45:33+00:00 955887c1fe90a2be056358001fd4920614a0f8b6 [ Upstream commit d68a90e148f5a82aa67654c5012071e31c0e4baa ] Controllers that are not yet enabled should not really enforce keep alive timeouts, but we still want to track a timeout and cleanup in case a host died before it enabled the controller. Hence, simply reset the keep alive timer when the controller is enabled. Suggested-by: Max Gurtovoy <maxg@mellanox.com> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit d68a90e148f5a82aa67654c5012071e31c0e4baa ]

Controllers that are not yet enabled should not really enforce keep alive
timeouts, but we still want to track a timeout and cleanup in case a host
died before it enabled the controller.  Hence, simply reset the keep
alive timer when the controller is enabled.

Suggested-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nvmet-fc: fix target sgl list on large transfers 2018-08-09T10:16:39+00:00 James Smart jsmart2021@gmail.com 2018-07-16T21:38:14+00:00 d626ac9669f29a4cd4d16ccf27349688a6dda2fd commit d082dc1562a2ff0947b214796f12faaa87e816a9 upstream. The existing code to carve up the sg list expected an sg element-per-page which can be very incorrect with iommu's remapping multiple memory pages to fewer bus addresses. To hit this error required a large io payload (greater than 256k) and a system that maps on a per-page basis. It's possible that large ios could get by fine if the system condensed the sgl list into the first 64 elements. This patch corrects the sg list handling by specifically walking the sg list element by element and attempting to divide the transfer up on a per-sg element boundary. While doing so, it still tries to keep sequences under 256k, but will exceed that rule if a single sg element is larger than 256k. Fixes: 48fa362b6c3f ("nvmet-fc: simplify sg list handling") Cc: <stable@vger.kernel.org> # 4.14 Signed-off-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit d082dc1562a2ff0947b214796f12faaa87e816a9 upstream.

The existing code to carve up the sg list expected an sg element-per-page
which can be very incorrect with iommu's remapping multiple memory pages
to fewer bus addresses. To hit this error required a large io payload
(greater than 256k) and a system that maps on a per-page basis. It's
possible that large ios could get by fine if the system condensed the
sgl list into the first 64 elements.

This patch corrects the sg list handling by specifically walking the
sg list element by element and attempting to divide the transfer up
on a per-sg element boundary. While doing so, it still tries to keep
sequences under 256k, but will exceed that rule if a single sg element
is larger than 256k.

Fixes: 48fa362b6c3f ("nvmet-fc: simplify sg list handling")
Cc: <stable@vger.kernel.org> # 4.14
Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nvme-pci: Fix queue double allocations 2018-08-09T10:16:39+00:00 Keith Busch keith.busch@intel.com 2018-01-23T16:16:19+00:00 4af9c61ad953ccc7dbd059a45e77e84db563bd41 commit 62314e405fa101dbb82563394f9dfc225e3f1167 upstream. The queue count says the highest queue that's been allocated, so don't reallocate a queue lower than that. Fixes: 147b27e4bd0 ("nvme-pci: allocate device queues storage space at probe") Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jon Derrick <jonathan.derrick@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 62314e405fa101dbb82563394f9dfc225e3f1167 upstream.

The queue count says the highest queue that's been allocated, so don't
reallocate a queue lower than that.

Fixes: 147b27e4bd0 ("nvme-pci: allocate device queues storage space at probe")
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
nvme-pci: allocate device queues storage space at probe 2018-08-09T10:16:39+00:00 Sagi Grimberg sagi@grimberg.me 2018-01-14T10:39:01+00:00 12c058df827213dcbbc42645fd5bcafb4057fb27 commit 147b27e4bd08406a6abebedbb478b431ec197be1 upstream. It may cause race by setting 'nvmeq' in nvme_init_request() because .init_request is called inside switching io scheduler, which may happen when the NVMe device is being resetted and its nvme queues are being freed and created. We don't have any sync between the two pathes. This patch changes the nvmeq allocation to occur at probe time so there is no way we can dereference it at init_request. [ 93.268391] kernel BUG at drivers/nvme/host/pci.c:408! [ 93.274146] invalid opcode: 0000 [#1] SMP [ 93.278618] Modules linked in: nfsv3 nfs_acl rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache sunrpc ipmi_ssif vfat fat intel_rapl sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel iTCO_wdt intel_cstate ipmi_si iTCO_vendor_support intel_uncore mxm_wmi mei_me ipmi_devintf intel_rapl_perf pcspkr sg ipmi_msghandler lpc_ich dcdbas mei shpchp acpi_power_meter wmi dm_multipath ip_tables xfs libcrc32c sd_mod mgag200 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm ahci libahci nvme libata crc32c_intel nvme_core tg3 megaraid_sas ptp i2c_core pps_core dm_mirror dm_region_hash dm_log dm_mod [ 93.349071] CPU: 5 PID: 1842 Comm: sh Not tainted 4.15.0-rc2.ming+ #4 [ 93.356256] Hardware name: Dell Inc. PowerEdge R730xd/072T6D, BIOS 2.5.5 08/16/2017 [ 93.364801] task: 00000000fb8abf2a task.stack: 0000000028bd82d1 [ 93.371408] RIP: 0010:nvme_init_request+0x36/0x40 [nvme] [ 93.377333] RSP: 0018:ffffc90002537ca8 EFLAGS: 00010246 [ 93.383161] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000008 [ 93.391122] RDX: 0000000000000000 RSI: ffff880276ae0000 RDI: ffff88047bae9008 [ 93.399084] RBP: ffff88047bae9008 R08: ffff88047bae9008 R09: 0000000009dabc00 [ 93.407045] R10: 0000000000000004 R11: 000000000000299c R12: ffff880186bc1f00 [ 93.415007] R13: ffff880276ae0000 R14: 0000000000000000 R15: 0000000000000071 [ 93.422969] FS: 00007f33cf288740(0000) GS:ffff88047ba80000(0000) knlGS:0000000000000000 [ 93.431996] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 93.438407] CR2: 00007f33cf28e000 CR3: 000000047e5bb006 CR4: 00000000001606e0 [ 93.446368] Call Trace: [ 93.449103] blk_mq_alloc_rqs+0x231/0x2a0 [ 93.453579] blk_mq_sched_alloc_tags.isra.8+0x42/0x80 [ 93.459214] blk_mq_init_sched+0x7e/0x140 [ 93.463687] elevator_switch+0x5a/0x1f0 [ 93.467966] ? elevator_get.isra.17+0x52/0xc0 [ 93.472826] elv_iosched_store+0xde/0x150 [ 93.477299] queue_attr_store+0x4e/0x90 [ 93.481580] kernfs_fop_write+0xfa/0x180 [ 93.485958] __vfs_write+0x33/0x170 [ 93.489851] ? __inode_security_revalidate+0x4c/0x60 [ 93.495390] ? selinux_file_permission+0xda/0x130 [ 93.500641] ? _cond_resched+0x15/0x30 [ 93.504815] vfs_write+0xad/0x1a0 [ 93.508512] SyS_write+0x52/0xc0 [ 93.512113] do_syscall_64+0x61/0x1a0 [ 93.516199] entry_SYSCALL64_slow_path+0x25/0x25 [ 93.521351] RIP: 0033:0x7f33ce96aab0 [ 93.525337] RSP: 002b:00007ffe57570238 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 93.533785] RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007f33ce96aab0 [ 93.541746] RDX: 0000000000000006 RSI: 00007f33cf28e000 RDI: 0000000000000001 [ 93.549707] RBP: 00007f33cf28e000 R08: 000000000000000a R09: 00007f33cf288740 [ 93.557669] R10: 00007f33cf288740 R11: 0000000000000246 R12: 00007f33cec42400 [ 93.565630] R13: 0000000000000006 R14: 0000000000000001 R15: 0000000000000000 [ 93.573592] Code: 4c 8d 40 08 4c 39 c7 74 16 48 8b 00 48 8b 04 08 48 85 c0 74 16 48 89 86 78 01 00 00 31 c0 c3 8d 4a 01 48 63 c9 48 c1 e1 03 eb de <0f> 0b 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 85 f6 53 48 89 [ 93.594676] RIP: nvme_init_request+0x36/0x40 [nvme] RSP: ffffc90002537ca8 [ 93.602273] ---[ end trace 810dde3993e5f14e ]--- Reported-by: Yi Zhang <yi.zhang@redhat.com> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jon Derrick <jonathan.derrick@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 147b27e4bd08406a6abebedbb478b431ec197be1 upstream.

It may cause race by setting 'nvmeq' in nvme_init_request()
because .init_request is called inside switching io scheduler, which
may happen when the NVMe device is being resetted and its nvme queues
are being freed and created. We don't have any sync between the two
pathes.

This patch changes the nvmeq allocation to occur at probe time so
there is no way we can dereference it at init_request.

[   93.268391] kernel BUG at drivers/nvme/host/pci.c:408!
[   93.274146] invalid opcode: 0000 [#1] SMP
[   93.278618] Modules linked in: nfsv3 nfs_acl rpcsec_gss_krb5 auth_rpcgss
nfsv4 dns_resolver nfs lockd grace fscache sunrpc ipmi_ssif vfat fat
intel_rapl sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel
kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel iTCO_wdt
intel_cstate ipmi_si iTCO_vendor_support intel_uncore mxm_wmi mei_me
ipmi_devintf intel_rapl_perf pcspkr sg ipmi_msghandler lpc_ich dcdbas mei
shpchp acpi_power_meter wmi dm_multipath ip_tables xfs libcrc32c sd_mod
mgag200 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt
fb_sys_fops ttm drm ahci libahci nvme libata crc32c_intel nvme_core tg3
megaraid_sas ptp i2c_core pps_core dm_mirror dm_region_hash dm_log dm_mod
[   93.349071] CPU: 5 PID: 1842 Comm: sh Not tainted 4.15.0-rc2.ming+ #4
[   93.356256] Hardware name: Dell Inc. PowerEdge R730xd/072T6D, BIOS 2.5.5 08/16/2017
[   93.364801] task: 00000000fb8abf2a task.stack: 0000000028bd82d1
[   93.371408] RIP: 0010:nvme_init_request+0x36/0x40 [nvme]
[   93.377333] RSP: 0018:ffffc90002537ca8 EFLAGS: 00010246
[   93.383161] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000008
[   93.391122] RDX: 0000000000000000 RSI: ffff880276ae0000 RDI: ffff88047bae9008
[   93.399084] RBP: ffff88047bae9008 R08: ffff88047bae9008 R09: 0000000009dabc00
[   93.407045] R10: 0000000000000004 R11: 000000000000299c R12: ffff880186bc1f00
[   93.415007] R13: ffff880276ae0000 R14: 0000000000000000 R15: 0000000000000071
[   93.422969] FS:  00007f33cf288740(0000) GS:ffff88047ba80000(0000) knlGS:0000000000000000
[   93.431996] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   93.438407] CR2: 00007f33cf28e000 CR3: 000000047e5bb006 CR4: 00000000001606e0
[   93.446368] Call Trace:
[   93.449103]  blk_mq_alloc_rqs+0x231/0x2a0
[   93.453579]  blk_mq_sched_alloc_tags.isra.8+0x42/0x80
[   93.459214]  blk_mq_init_sched+0x7e/0x140
[   93.463687]  elevator_switch+0x5a/0x1f0
[   93.467966]  ? elevator_get.isra.17+0x52/0xc0
[   93.472826]  elv_iosched_store+0xde/0x150
[   93.477299]  queue_attr_store+0x4e/0x90
[   93.481580]  kernfs_fop_write+0xfa/0x180
[   93.485958]  __vfs_write+0x33/0x170
[   93.489851]  ? __inode_security_revalidate+0x4c/0x60
[   93.495390]  ? selinux_file_permission+0xda/0x130
[   93.500641]  ? _cond_resched+0x15/0x30
[   93.504815]  vfs_write+0xad/0x1a0
[   93.508512]  SyS_write+0x52/0xc0
[   93.512113]  do_syscall_64+0x61/0x1a0
[   93.516199]  entry_SYSCALL64_slow_path+0x25/0x25
[   93.521351] RIP: 0033:0x7f33ce96aab0
[   93.525337] RSP: 002b:00007ffe57570238 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[   93.533785] RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007f33ce96aab0
[   93.541746] RDX: 0000000000000006 RSI: 00007f33cf28e000 RDI: 0000000000000001
[   93.549707] RBP: 00007f33cf28e000 R08: 000000000000000a R09: 00007f33cf288740
[   93.557669] R10: 00007f33cf288740 R11: 0000000000000246 R12: 00007f33cec42400
[   93.565630] R13: 0000000000000006 R14: 0000000000000001 R15: 0000000000000000
[   93.573592] Code: 4c 8d 40 08 4c 39 c7 74 16 48 8b 00 48 8b 04 08 48 85 c0
74 16 48 89 86 78 01 00 00 31 c0 c3 8d 4a 01 48 63 c9 48 c1 e1 03 eb de <0f>
0b 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 85 f6 53 48 89
[   93.594676] RIP: nvme_init_request+0x36/0x40 [nvme] RSP: ffffc90002537ca8
[   93.602273] ---[ end trace 810dde3993e5f14e ]---

Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>