From: Sagi Grimberg sagi@grimberg.me
[ Upstream commit ecca390e80561debbfdb4dc96bf94595136889fa ]
A deadlock happens in the following scenario with multipath: 1) scan_work(nvme0) detects a new nsid while nvme0 is an optimized path to it, path nvme1 happens to be inaccessible.
2) Before scan_work is complete nvme0 disconnect is initiated nvme_delete_ctrl_sync() sets nvme0 state to NVME_CTRL_DELETING
3) scan_work(1) attempts to submit IO, but nvme_path_is_optimized() observes nvme0 is not LIVE. Since nvme1 is a possible path IO is requeued and scan_work hangs.
-- Workqueue: nvme-wq nvme_scan_work [nvme_core] kernel: Call Trace: kernel: __schedule+0x2b9/0x6c0 kernel: schedule+0x42/0xb0 kernel: io_schedule+0x16/0x40 kernel: do_read_cache_page+0x438/0x830 kernel: read_cache_page+0x12/0x20 kernel: read_dev_sector+0x27/0xc0 kernel: read_lba+0xc1/0x220 kernel: efi_partition+0x1e6/0x708 kernel: check_partition+0x154/0x244 kernel: rescan_partitions+0xae/0x280 kernel: __blkdev_get+0x40f/0x560 kernel: blkdev_get+0x3d/0x140 kernel: __device_add_disk+0x388/0x480 kernel: device_add_disk+0x13/0x20 kernel: nvme_mpath_set_live+0x119/0x140 [nvme_core] kernel: nvme_update_ns_ana_state+0x5c/0x60 [nvme_core] kernel: nvme_set_ns_ana_state+0x1e/0x30 [nvme_core] kernel: nvme_parse_ana_log+0xa1/0x180 [nvme_core] kernel: nvme_mpath_add_disk+0x47/0x90 [nvme_core] kernel: nvme_validate_ns+0x396/0x940 [nvme_core] kernel: nvme_scan_work+0x24f/0x380 [nvme_core] kernel: process_one_work+0x1db/0x380 kernel: worker_thread+0x249/0x400 kernel: kthread+0x104/0x140 --
4) Delete also hangs in flush_work(ctrl->scan_work) from nvme_remove_namespaces().
Similiarly a deadlock with ana_work may happen: if ana_work has started and calls nvme_mpath_set_live and device_add_disk, it will trigger I/O. When we trigger disconnect I/O will block because our accessible (optimized) path is disconnecting, but the alternate path is inaccessible, so I/O blocks. Then disconnect tries to flush the ana_work and hangs.
[ 605.550896] Workqueue: nvme-wq nvme_ana_work [nvme_core] [ 605.552087] Call Trace: [ 605.552683] __schedule+0x2b9/0x6c0 [ 605.553507] schedule+0x42/0xb0 [ 605.554201] io_schedule+0x16/0x40 [ 605.555012] do_read_cache_page+0x438/0x830 [ 605.556925] read_cache_page+0x12/0x20 [ 605.557757] read_dev_sector+0x27/0xc0 [ 605.558587] amiga_partition+0x4d/0x4c5 [ 605.561278] check_partition+0x154/0x244 [ 605.562138] rescan_partitions+0xae/0x280 [ 605.563076] __blkdev_get+0x40f/0x560 [ 605.563830] blkdev_get+0x3d/0x140 [ 605.564500] __device_add_disk+0x388/0x480 [ 605.565316] device_add_disk+0x13/0x20 [ 605.566070] nvme_mpath_set_live+0x5e/0x130 [nvme_core] [ 605.567114] nvme_update_ns_ana_state+0x2c/0x30 [nvme_core] [ 605.568197] nvme_update_ana_state+0xca/0xe0 [nvme_core] [ 605.569360] nvme_parse_ana_log+0xa1/0x180 [nvme_core] [ 605.571385] nvme_read_ana_log+0x76/0x100 [nvme_core] [ 605.572376] nvme_ana_work+0x15/0x20 [nvme_core] [ 605.573330] process_one_work+0x1db/0x380 [ 605.574144] worker_thread+0x4d/0x400 [ 605.574896] kthread+0x104/0x140 [ 605.577205] ret_from_fork+0x35/0x40 [ 605.577955] INFO: task nvme:14044 blocked for more than 120 seconds. [ 605.579239] Tainted: G OE 5.3.5-050305-generic #201910071830 [ 605.580712] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 605.582320] nvme D 0 14044 14043 0x00000000 [ 605.583424] Call Trace: [ 605.583935] __schedule+0x2b9/0x6c0 [ 605.584625] schedule+0x42/0xb0 [ 605.585290] schedule_timeout+0x203/0x2f0 [ 605.588493] wait_for_completion+0xb1/0x120 [ 605.590066] __flush_work+0x123/0x1d0 [ 605.591758] __cancel_work_timer+0x10e/0x190 [ 605.593542] cancel_work_sync+0x10/0x20 [ 605.594347] nvme_mpath_stop+0x2f/0x40 [nvme_core] [ 605.595328] nvme_stop_ctrl+0x12/0x50 [nvme_core] [ 605.596262] nvme_do_delete_ctrl+0x3f/0x90 [nvme_core] [ 605.597333] nvme_sysfs_delete+0x5c/0x70 [nvme_core] [ 605.598320] dev_attr_store+0x17/0x30
Fix this by introducing a new state: NVME_CTRL_DELETE_NOIO, which will indicate the phase of controller deletion where I/O cannot be allowed to access the namespace. NVME_CTRL_DELETING still allows mpath I/O to be issued to the bottom device, and only after we flush the ana_work and scan_work (after nvme_stop_ctrl and nvme_prep_remove_namespaces) we change the state to NVME_CTRL_DELETING_NOIO. Also we prevent ana_work from re-firing by aborting early if we are not LIVE, so we should be safe here.
In addition, change the transport drivers to follow the updated state machine.
Fixes: 0d0b660f214d ("nvme: add ANA support") Reported-by: Anton Eidelman anton@lightbitslabs.com Signed-off-by: Sagi Grimberg sagi@grimberg.me Signed-off-by: Christoph Hellwig hch@lst.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/nvme/host/core.c | 15 +++++++++++++++ drivers/nvme/host/fabrics.c | 2 +- drivers/nvme/host/fabrics.h | 3 ++- drivers/nvme/host/fc.c | 1 + drivers/nvme/host/multipath.c | 18 +++++++++++++++--- drivers/nvme/host/nvme.h | 1 + drivers/nvme/host/rdma.c | 10 ++++++---- drivers/nvme/host/tcp.c | 15 +++++++++------ 8 files changed, 50 insertions(+), 15 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index f7540a9e54fd2..ee67113d96b1b 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -368,6 +368,16 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl, break; } break; + case NVME_CTRL_DELETING_NOIO: + switch (old_state) { + case NVME_CTRL_DELETING: + case NVME_CTRL_DEAD: + changed = true; + /* FALLTHRU */ + default: + break; + } + break; case NVME_CTRL_DEAD: switch (old_state) { case NVME_CTRL_DELETING: @@ -405,6 +415,7 @@ static bool nvme_state_terminal(struct nvme_ctrl *ctrl) case NVME_CTRL_CONNECTING: return false; case NVME_CTRL_DELETING: + case NVME_CTRL_DELETING_NOIO: case NVME_CTRL_DEAD: return true; default: @@ -3280,6 +3291,7 @@ static ssize_t nvme_sysfs_show_state(struct device *dev, [NVME_CTRL_RESETTING] = "resetting", [NVME_CTRL_CONNECTING] = "connecting", [NVME_CTRL_DELETING] = "deleting", + [NVME_CTRL_DELETING_NOIO]= "deleting (no IO)", [NVME_CTRL_DEAD] = "dead", };
@@ -3860,6 +3872,9 @@ void nvme_remove_namespaces(struct nvme_ctrl *ctrl) if (ctrl->state == NVME_CTRL_DEAD) nvme_kill_queues(ctrl);
+ /* this is a no-op when called from the controller reset handler */ + nvme_change_ctrl_state(ctrl, NVME_CTRL_DELETING_NOIO); + down_write(&ctrl->namespaces_rwsem); list_splice_init(&ctrl->namespaces, &ns_list); up_write(&ctrl->namespaces_rwsem); diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c index 2a6c8190eeb76..4ec4829d62334 100644 --- a/drivers/nvme/host/fabrics.c +++ b/drivers/nvme/host/fabrics.c @@ -547,7 +547,7 @@ static struct nvmf_transport_ops *nvmf_lookup_transport( blk_status_t nvmf_fail_nonready_command(struct nvme_ctrl *ctrl, struct request *rq) { - if (ctrl->state != NVME_CTRL_DELETING && + if (ctrl->state != NVME_CTRL_DELETING_NOIO && ctrl->state != NVME_CTRL_DEAD && !blk_noretry_request(rq) && !(rq->cmd_flags & REQ_NVME_MPATH)) return BLK_STS_RESOURCE; diff --git a/drivers/nvme/host/fabrics.h b/drivers/nvme/host/fabrics.h index a0ec40ab62eeb..a9c1e3b4585ec 100644 --- a/drivers/nvme/host/fabrics.h +++ b/drivers/nvme/host/fabrics.h @@ -182,7 +182,8 @@ bool nvmf_ip_options_match(struct nvme_ctrl *ctrl, static inline bool nvmf_check_ready(struct nvme_ctrl *ctrl, struct request *rq, bool queue_live) { - if (likely(ctrl->state == NVME_CTRL_LIVE)) + if (likely(ctrl->state == NVME_CTRL_LIVE || + ctrl->state == NVME_CTRL_DELETING)) return true; return __nvmf_check_ready(ctrl, rq, queue_live); } diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c index 564e3f220ac79..a70220df1f570 100644 --- a/drivers/nvme/host/fc.c +++ b/drivers/nvme/host/fc.c @@ -800,6 +800,7 @@ nvme_fc_ctrl_connectivity_loss(struct nvme_fc_ctrl *ctrl) break;
case NVME_CTRL_DELETING: + case NVME_CTRL_DELETING_NOIO: default: /* no action to take - let it delete */ break; diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index d3914b7e8f52c..8f235fbfe44ee 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -167,9 +167,18 @@ void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl)
static bool nvme_path_is_disabled(struct nvme_ns *ns) { - return ns->ctrl->state != NVME_CTRL_LIVE || - test_bit(NVME_NS_ANA_PENDING, &ns->flags) || - test_bit(NVME_NS_REMOVING, &ns->flags); + /* + * We don't treat NVME_CTRL_DELETING as a disabled path as I/O should + * still be able to complete assuming that the controller is connected. + * Otherwise it will fail immediately and return to the requeue list. + */ + if (ns->ctrl->state != NVME_CTRL_LIVE && + ns->ctrl->state != NVME_CTRL_DELETING) + return true; + if (test_bit(NVME_NS_ANA_PENDING, &ns->flags) || + test_bit(NVME_NS_REMOVING, &ns->flags)) + return true; + return false; }
static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head, int node) @@ -575,6 +584,9 @@ static void nvme_ana_work(struct work_struct *work) { struct nvme_ctrl *ctrl = container_of(work, struct nvme_ctrl, ana_work);
+ if (ctrl->state != NVME_CTRL_LIVE) + return; + nvme_read_ana_log(ctrl); }
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index 8f1b0a30fd2a6..ff0b4079e8d6d 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -183,6 +183,7 @@ enum nvme_ctrl_state { NVME_CTRL_RESETTING, NVME_CTRL_CONNECTING, NVME_CTRL_DELETING, + NVME_CTRL_DELETING_NOIO, NVME_CTRL_DEAD, };
diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c index 19c94080512cf..fdab0054cd809 100644 --- a/drivers/nvme/host/rdma.c +++ b/drivers/nvme/host/rdma.c @@ -1023,11 +1023,12 @@ static int nvme_rdma_setup_ctrl(struct nvme_rdma_ctrl *ctrl, bool new) changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE); if (!changed) { /* - * state change failure is ok if we're in DELETING state, + * state change failure is ok if we started ctrl delete, * unless we're during creation of a new controller to * avoid races with teardown flow. */ - WARN_ON_ONCE(ctrl->ctrl.state != NVME_CTRL_DELETING); + WARN_ON_ONCE(ctrl->ctrl.state != NVME_CTRL_DELETING && + ctrl->ctrl.state != NVME_CTRL_DELETING_NOIO); WARN_ON_ONCE(new); ret = -EINVAL; goto destroy_io; @@ -1080,8 +1081,9 @@ static void nvme_rdma_error_recovery_work(struct work_struct *work) blk_mq_unquiesce_queue(ctrl->ctrl.admin_q);
if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_CONNECTING)) { - /* state change failure is ok if we're in DELETING state */ - WARN_ON_ONCE(ctrl->ctrl.state != NVME_CTRL_DELETING); + /* state change failure is ok if we started ctrl delete */ + WARN_ON_ONCE(ctrl->ctrl.state != NVME_CTRL_DELETING && + ctrl->ctrl.state != NVME_CTRL_DELETING_NOIO); return; }
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c index 99eaa0474e10b..06d6c1c6de35b 100644 --- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -1938,11 +1938,12 @@ static int nvme_tcp_setup_ctrl(struct nvme_ctrl *ctrl, bool new)
if (!nvme_change_ctrl_state(ctrl, NVME_CTRL_LIVE)) { /* - * state change failure is ok if we're in DELETING state, + * state change failure is ok if we started ctrl delete, * unless we're during creation of a new controller to * avoid races with teardown flow. */ - WARN_ON_ONCE(ctrl->state != NVME_CTRL_DELETING); + WARN_ON_ONCE(ctrl->state != NVME_CTRL_DELETING && + ctrl->state != NVME_CTRL_DELETING_NOIO); WARN_ON_ONCE(new); ret = -EINVAL; goto destroy_io; @@ -1998,8 +1999,9 @@ static void nvme_tcp_error_recovery_work(struct work_struct *work) blk_mq_unquiesce_queue(ctrl->admin_q);
if (!nvme_change_ctrl_state(ctrl, NVME_CTRL_CONNECTING)) { - /* state change failure is ok if we're in DELETING state */ - WARN_ON_ONCE(ctrl->state != NVME_CTRL_DELETING); + /* state change failure is ok if we started ctrl delete */ + WARN_ON_ONCE(ctrl->state != NVME_CTRL_DELETING && + ctrl->state != NVME_CTRL_DELETING_NOIO); return; }
@@ -2034,8 +2036,9 @@ static void nvme_reset_ctrl_work(struct work_struct *work) nvme_tcp_teardown_ctrl(ctrl, false);
if (!nvme_change_ctrl_state(ctrl, NVME_CTRL_CONNECTING)) { - /* state change failure is ok if we're in DELETING state */ - WARN_ON_ONCE(ctrl->state != NVME_CTRL_DELETING); + /* state change failure is ok if we started ctrl delete */ + WARN_ON_ONCE(ctrl->state != NVME_CTRL_DELETING && + ctrl->state != NVME_CTRL_DELETING_NOIO); return; }