current switch partition only check if kfd_processes_table is empty.
kfd_prcesses_table entry is deleted in kfd_process_notifier_release, but
kfd_process tear down is in kfd_process_wq_release.

Process A workqueue -> kfd_process_wq_release -> Access kfd_node member
Process B switch partition -> amdgpu_xcp_pre_partition_switch -> 
amdgpu_amdkfd_device_fini_sw
-> kfd_node tear down.

Process A and B may trigger a race as below:

This patch is to resolve the race by adding an atomic kfd_process counter
kfd_processes_count, it increment as create kfd process, decrement as
finish kfd_process_wq_release.

[3966658.307702] divide error: 0000 [#1] SMP NOPTI
[3966658.350818]  i10nm_edac
[3966658.356318] CPU: 124 PID: 38435 Comm: kworker/124:0 Kdump: loaded Tainted
[3966658.356890] Workqueue: kfd_process_wq kfd_process_wq_release [amdgpu]
[3966658.362839]  nfit
[3966658.366457] RIP: 0010:kfd_get_num_sdma_engines+0x17/0x40 [amdgpu]
[3966658.366460] Code: 00 00 e9 ac 81 02 00 66 66 2e 0f 1f 84 00 00 00 00 00 90 
0f 1f 44 00 00 48 8b 4f 08 48 8b b7 00 01 00 00 8b 81 58 26 03 00 99 <f7> be b8 
01 00 00 80 b9 70 2e 00 00 00 74 0b 83 f8 02 ba 02 00 00
[3966658.380967]  x86_pkg_temp_thermal
[3966658.391529] RSP: 0018:ffffc900a0edfdd8 EFLAGS: 00010246
[3966658.391531] RAX: 0000000000000008 RBX: ffff8974e593b800 RCX: 
ffff888645900000
[3966658.391531] RDX: 0000000000000000 RSI: ffff888129154400 RDI: 
ffff888129151c00
[3966658.391532] RBP: ffff8883ad79d400 R08: 0000000000000000 R09: 
ffff8890d2750af4
[3966658.391532] R10: 0000000000000018 R11: 0000000000000018 R12: 
0000000000000000
[3966658.391533] R13: ffff8883ad79d400 R14: ffffe87ff662ba00 R15: 
ffff8974e593b800
[3966658.391533] FS:  0000000000000000(0000) GS:ffff88fe7f600000(0000) 
knlGS:0000000000000000
[3966658.391534] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[3966658.391534] CR2: 0000000000d71000 CR3: 000000dd0e970004 CR4: 
0000000002770ee0
[3966658.391535] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 
0000000000000000
[3966658.391535] DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 
0000000000000400
[3966658.391536] PKRU: 55555554
[3966658.391536] Call Trace:
[3966658.391674]  deallocate_sdma_queue+0x38/0xa0 [amdgpu]
[3966658.391762]  process_termination_cpsch+0x1ed/0x480 [amdgpu]
[3966658.399754]  intel_powerclamp
[3966658.402831]  kfd_process_dequeue_from_all_devices+0x5b/0xc0 [amdgpu]
[3966658.402908]  kfd_process_wq_release+0x1a/0x1a0 [amdgpu]
[3966658.410516]  coretemp
[3966658.434016]  process_one_work+0x1ad/0x380
[3966658.434021]  worker_thread+0x49/0x310
[3966658.438963]  kvm_intel
[3966658.446041]  ? process_one_work+0x380/0x380
[3966658.446045]  kthread+0x118/0x140
[3966658.446047]  ? __kthread_bind_mask+0x60/0x60
[3966658.446050]  ret_from_fork+0x1f/0x30
[3966658.446053] Modules linked in: kpatch_20765354(OEK)
[3966658.455310]  kvm
[3966658.464534]  mptcp_diag xsk_diag raw_diag unix_diag af_packet_diag 
netlink_diag udp_diag act_pedit act_mirred act_vlan cls_flower 
kpatch_21951273(OEK) kpatch_18424469(OEK) kpatch_19749756(OEK)
[3966658.473462]  idxd_mdev
[3966658.482306]  kpatch_17971294(OEK) sch_ingress xt_conntrack amdgpu(OE) 
amdxcp(OE) amddrm_buddy(OE) amd_sched(OE) amdttm(OE) amdkcl(OE) intel_ifs 
iptable_mangle tcm_loop target_core_pscsi tcp_diag target_core_file inet_diag 
target_core_iblock target_core_user target_core_mod coldpgs 
kpatch_18383292(OEK) ip6table_nat ip6table_filter ip6_tables 
ip_set_hash_ipportip ip_set_hash_ipportnet ip_set_hash_ipport 
ip_set_bitmap_port xt_comment iptable_nat nf_nat iptable_filter ip_tables 
ip_set ip_vs_sh ip_vs_wrr ip_vs_rr ip_vs nf_conntrack nf_defrag_ipv6 
nf_defrag_ipv4 sn_core_odd(OE) i40e overlay binfmt_misc tun bonding(OE) 
aisqos(OE) aisqos_hotfixes(OE) rfkill uio_pci_generic uio cuse fuse nf_tables 
nfnetlink intel_rapl_msr intel_rapl_common intel_uncore_frequency 
intel_uncore_frequency_common i10nm_edac nfit x86_pkg_temp_thermal 
intel_powerclamp coretemp kvm_intel kvm idxd_mdev
[3966658.491237]  vfio_pci
[3966658.501196]  vfio_pci vfio_virqfd mdev vfio_iommu_type1 vfio iax_crypto 
intel_pmt_telemetry iTCO_wdt intel_pmt_class iTCO_vendor_support irqbypass 
crct10dif_pclmul crc32_pclmul ghash_clmulni_intel rapl intel_cstate 
snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_hda_core snd_hwdep snd_seq
[3966658.508537]  vfio_virqfd
[3966658.517569]  snd_seq_device ipmi_ssif isst_if_mbox_pci isst_if_mmio pcspkr 
snd_pcm idxd intel_uncore ses isst_if_common intel_vsec idxd_bus enclosure 
snd_timer mei_me snd i2c_i801 i2c_smbus mei i2c_ismt soundcore joydev acpi_ipmi 
ipmi_si ipmi_devintf ipmi_msghandler acpi_power_meter acpi_pad vfat fat
[3966658.526851]  mdev
[3966658.536096]  nfsd auth_rpcgss nfs_acl lockd grace slb_vtoa(OE) sunrpc 
dm_mod hookers mlx5_ib(OE) ast i2c_algo_bit drm_vram_helper drm_kms_helper 
syscopyarea sysfillrect sysimgblt fb_sys_fops drm_ttm_helper ttm mlx5_core(OE) 
mlxfw(OE)
[3966658.540381]  vfio_iommu_type1
[3966658.544341]  nvme mpt3sas tls drm nvme_core pci_hyperv_intf raid_class 
psample libcrc32c crc32c_intel mlxdevm(OE) i2c_core
[3966658.551254]  vfio
[3966658.558742]  scsi_transport_sas wmi pinctrl_emmitsburg sd_mod t10_pi sg 
ahci libahci libata rdma_ucm(OE) ib_uverbs(OE) rdma_cm(OE) iw_cm(OE) ib_cm(OE) 
ib_umad(OE) ib_core(OE) ib_ucm(OE) mlx_compat(OE)
[3966658.563004]  iax_crypto
[3966658.570988]  [last unloaded: diagnose]
[3966658.571027] ---[ end trace cc9dbb180f9ae537 ]---

Signed-off-by: Yifan Zhang <yifan1.zh...@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_device.c  | 6 ++++++
 drivers/gpu/drm/amd/amdkfd/kfd_priv.h    | 2 ++
 drivers/gpu/drm/amd/amdkfd/kfd_process.c | 6 ++++++
 3 files changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
index 5649cdb3f9c2..1cdb21c90bd3 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
@@ -1521,6 +1521,12 @@ int kgd2kfd_check_and_lock_kfd(struct kfd_dev *kfd)
 
 proc_check_unlock:
        srcu_read_unlock(&kfd_processes_srcu, idx);
+
+       if (!!atomic_read(&kfd_processes_count)) {
+               pr_info("process_wq_release not finished\n");
+               return -EBUSY;
+       }
+
 out:
        if (!r)
                ++kfd->kfd_dev_lock;
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h 
b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index d01ef5ac0766..870c621a410a 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -204,6 +204,8 @@ extern bool debug_evictions;
 
 extern struct mutex kfd_processes_mutex;
 
+extern atomic_t kfd_processes_count;
+
 enum cache_policy {
        cache_policy_coherent,
        cache_policy_noncoherent
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
index 5be28c6c4f6a..c1d9799bf94e 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -52,6 +52,8 @@ struct mm_struct;
 DEFINE_HASHTABLE(kfd_processes_table, KFD_PROCESS_TABLE_SIZE);
 DEFINE_MUTEX(kfd_processes_mutex);
 
+atomic_t kfd_processes_count;
+
 DEFINE_SRCU(kfd_processes_srcu);
 
 /* For process termination handling */
@@ -871,6 +873,8 @@ struct kfd_process *kfd_create_process(struct task_struct 
*thread)
                if (IS_ERR(process))
                        goto out;
 
+               atomic_inc(&kfd_processes_count);
+
                if (!procfs.kobj)
                        goto out;
 
@@ -1194,6 +1198,8 @@ static void kfd_process_wq_release(struct work_struct 
*work)
        put_task_struct(p->lead_thread);
 
        kfree(p);
+
+       atomic_dec(&kfd_processes_count);
 }
 
 static void kfd_process_ref_release(struct kref *ref)
-- 
2.43.0

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