[linux-nvidia-bos] Set LED_HW_PLUGGABLE for NPEM and fix class init ordering issue of CXL/fwctl by nvax-r · Pull Request #387 · NVIDIA/NV-Kernels

nvax-r · 2026-04-23T01:54:55Z

Description

This backport adds fixes for issue encountered when doing CXL device hotplug.

Set LED_HW_PLUGGABLE for NPEM - Add the flag LED_HW_PLUGGABLE since NPEM LEDs are on
hot-pluggable hardware by nature.
Fix class init ordering on CXL device removal - Use subsys_initcall() to correct the initialization ordering of CXL and fwctl subsystem.

Source

Patch Breakdown (2 patches):

#	Category	Count	Source
1	Richard Cheng's PCI/NPEM: Set LED_HW_PLUGGABLE for hotplug-capable ports	1	LKML (v1, merged and applied to v7.1
2	Richard Cheng's fwctl: Fix class init ordering to avoid NULL pointer dereference on device removal	1	LKML (v1, merged and applied to v7.1 )

Lore Links:

Richard Cheng's PCI/NPEM: Set LED_HW_PLUGGABLE for hotplug-capable ports (v1, applied to v7.1): https://lore.kernel.org/all/20260402093850.23075-1-icheng@nvidia.com/
Richard Cheng's fwctl: Fix class init ordering to avoid NULL pointer dereference on device removal (v1, applied to v7.1): https://lore.kernel.org/all/20260409051902.40218-1-icheng@nvidia.com/

Upstream Status

Series	Status
Richard NPEM v1	Applied to v7.1 and merged
Richard fwctl v1	Applied to v7.1 and merged

Testing

Build Validation:

Built successfully for ARM 64 4k page size kernel
Built successfully for ARM 64 64k page size kernel

Config Verification:

CXL-related configs enabled as expected:

CONFIG_ACPI_APEI_EINJ_CXL=y
CONFIG_PCI_CXL=y
CONFIG_CXL_BUS=y
CONFIG_CXL_PCI=y
CONFIG_CXL_MEM_RAW_COMMANDS=y
CONFIG_CXL_ACPI=m
CONFIG_CXL_PMEM=m
CONFIG_CXL_MEM=y
CONFIG_CXL_FEATURES=y
# CONFIG_CXL_EDAC_MEM_FEATURES is not set
CONFIG_CXL_PORT=y
CONFIG_CXL_SUSPEND=y
CONFIG_CXL_REGION=y
# CONFIG_CXL_REGION_INVALIDATION_TEST is not set
CONFIG_CXL_RAS=y
# CONFIG_CACHEMAINT_FOR_HOTPLUG is not set
# CONFIG_SFC_CXL is not set
CONFIG_CXL_PMU=m
CONFIG_DEV_DAX=y
CONFIG_DEV_DAX_PMEM=m
CONFIG_DEV_DAX_HMEM=m
CONFIG_DEV_DAX_CXL=y
CONFIG_DEV_DAX_HMEM_DEVICES=y
CONFIG_DEV_DAX_KMEM=y
CONFIG_ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION=y
CONFIG_GENERIC_CPU_CACHE_MAINTENANCE=y

fwctl config needs to be enabled ,too

CONFIG_FWCTL=y

Runtime Testing:

Boot test on ARM64 system
CXL device enumeration test (ls /sys/bus/cxl/devices/)
CXL interleaving testing
CXL reset test (echo 1 > /sys/bus/pci/devices//cxl_reset)
CXL hotplug test

Notes

If you need a full CXL type 2-capable kernel, Jiandi's backport should be added as well.
Since these 2 patches are bug fixes and independent of them, we can backport them seperately.

LP: https://bugs.launchpad.net/ubuntu/+source/linux-nvidia-6.17/+bug/2149918

NPEM registers LED classdevs on PCI endpoint that may be behind hotplug-capable ports. During hot-removal, led_classdev_unregister() calls led_set_brightness(LED_OFF) which leads to a PCI config read to a disconnected device, which fails and returns -ENODEV (topology details in msgid.link below): leds 0003:01:00.0:enclosure:ok: Setting an LED's brightness failed (-19) The LED core already suppresses this for devices with LED_HW_PLUGGABLE set, but NPEM never sets it. Add the flag since NPEM LEDs are on hot-pluggable hardware by nature. Fixes: 4e89354 ("PCI/NPEM: Add Native PCIe Enclosure Management support") Signed-off-by: Richard Cheng <icheng@nvidia.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Lukas Wunner <lukas@wunner.de> Acked-by: Kai-Heng Feng <kaihengf@nvidia.com> Link: https://patch.msgid.link/20260402093850.23075-1-icheng@nvidia.com (cherry picked from commit 16d021c) Signed-off-by: Richard Cheng <icheng@nvidia.com>

…evice removal CXL is linked before fwctl in drivers/Makefile. Both use `module_init, so `cxl_pci_driver_init()` runs first. When `cxl_pci_probe()` calls `fwctl_register()` and then `device_add()`, fwctl_class is not yet registered because fwctl_init() hasn't run, causing `class_to_subsys()` to return NULL and skip knode_class initialization. On device removal, `class_to_subsys()` returns non-NULL, and `device_del()` calls `klist_del()` on the uninitialized knode, triggering a NULL pointer dereference. Fixes: 858ce2f ("cxl: Add FWCTL support to CXL") Link: https://patch.msgid.link/r/20260409051902.40218-1-icheng@nvidia.com Signed-off-by: Richard Cheng <icheng@nvidia.com> Reviewed-by: Kai-Heng Feng <kaihengf@nvidia.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> (cherry picked from commit a55f802) Signed-off-by: Richard Cheng <icheng@nvidia.com>

github-actions · 2026-04-23T02:05:52Z

✅ Patchscan: No Missing Fixes

All cherry-picked commits have been checked — no missing upstream fixes found.

clsotog · 2026-04-23T03:37:03Z

Acked-by: Carol L Soto <csoto@nvidia.com>

nirmoy

Acked-by: Nirmoy Das <nirmoyd@nvidia.com>

nvmochs

Verified these are clean picks that match upstream.

Acked-by: Matthew R. Ochs <mochs@nvidia.com>

nvmochs · 2026-04-23T14:56:35Z

Merged, closing PR.

53c2516d4e61 (nresolute/nvidia-bos-next) fwctl: Fix class init ordering to avoid NULL pointer dereference on device removal
beda472d4637 PCI/NPEM: Set LED_HW_PLUGGABLE for hotplug-capable ports

…ve pages Device private and exclusive entries are only supported for anonymous folios. This condition is tested in __migrate_device_pages() and make_device_exclusive() using folio_test_anon(). However the unmap path tests this assumption using vma_is_anonymous(). This is wrong because whilst anonymous VMAs can only contain folios where folio_test_anon() is true the opposite relation does not hold. A folio for which folio_test_anon() is true does not imply vma_is_anonymous() is true. Such a condition can occur if for example a folio is part of a private filebacked mapping. In this case vma_is_anonymous() is false as the mapping is filebacked, but folio_test_anon() may be true, thus permitting devices to migrate the folio to device private memory. This can lead to the following spurious warnings during process teardown: [ 772.737706] ------------[ cut here ]------------ [ 772.739201] WARNING: mm/memory.c:1754 at unmap_page_range.cold+0x26/0x18a, CPU#17: hmm-tests/2041 [ 772.742050] Modules linked in: test_hmm nvidia_uvm(O) nvidia(O) [ 772.743959] CPU: 17 UID: 0 PID: 2041 Comm: hmm-tests Tainted: G W O 7.0.0+ #387 PREEMPT(full) [ 772.747104] Tainted: [W]=WARN, [O]=OOT_MODULE [ 772.748509] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 [ 772.752117] RIP: 0010:unmap_page_range.cold+0x26/0x18a [ 772.753780] Code: 7e fe ff ff 48 89 4c 24 78 4c 89 44 24 38 e8 f2 ff b1 00 48 8b 4c 24 78 4c 8b 44 24 38 48 8b 44 24 18 48 83 78 48 00 74 04 90 <0f> 0b 90 48 89 ca b8 ff ff 37 00 48 c1 ea 03 48 c1 e0 2a 80 3c 02 [ 772.759602] RSP: 0018:ffff888112607550 EFLAGS: 00010286 [ 772.761310] RAX: ffff88811bbf4dc0 RBX: dffffc0000000000 RCX: ffffea03e9bfffd8 [ 772.763583] RDX: 1ffff1102377e9c1 RSI: 0000000000000008 RDI: ffff88811bbf4e08 [ 772.765914] RBP: 0000000000000006 R08: ffff8881059f7448 R09: ffffed10224c0e68 [ 772.768184] R10: ffff888112607347 R11: 0000000000000001 R12: 0000000000000001 [ 772.770461] R13: ffffea03e9bfffc0 R14: ffff888112607908 R15: ffffea03e9bfffc0 [ 772.772782] FS: 00007f327caa2780(0000) GS:ffff888427b7d000(0000) knlGS:0000000000000000 [ 772.775328] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 772.777187] CR2: 00007f327ca89000 CR3: 00000001994d5000 CR4: 00000000000006f0 [ 772.779135] Call Trace: [ 772.779792] <TASK> [ 772.780317] ? dmirror_interval_invalidate+0x1a3/0x290 [test_hmm] [ 772.781873] ? vm_normal_page_pud+0x2b0/0x2b0 [ 772.782992] ? __rwlock_init+0x150/0x150 [ 772.784006] ? lock_release+0x216/0x2b0 [ 772.785008] ? __mmu_notifier_invalidate_range_start+0x505/0x6e0 [ 772.786522] ? lock_release+0x216/0x2b0 [ 772.787498] ? unmap_single_vma+0xb6/0x210 [ 772.788573] unmap_vmas+0x27d/0x520 [ 772.789506] ? unmap_single_vma+0x210/0x210 [ 772.790607] ? mas_update_gap.part.0+0x620/0x620 [ 772.791834] unmap_region+0x19e/0x350 [ 772.792769] ? remove_vma+0x130/0x130 [ 772.793684] ? mas_alloc_nodes+0x1f2/0x300 [ 772.794730] vms_complete_munmap_vmas+0x8c1/0xe20 [ 772.795926] ? unmap_region+0x350/0x350 [ 772.796917] do_vmi_align_munmap+0x36a/0x4e0 [ 772.798018] ? lock_release+0x216/0x2b0 [ 772.799024] ? vma_shrink+0x620/0x620 [ 772.799983] do_vmi_munmap+0x150/0x2c0 [ 772.800939] __vm_munmap+0x161/0x2c0 [ 772.801872] ? expand_downwards+0xd60/0xd60 [ 772.802948] ? clockevents_program_event+0x1ef/0x540 [ 772.804217] ? lock_release+0x216/0x2b0 [ 772.805158] __x64_sys_munmap+0x59/0x80 [ 772.805776] do_syscall_64+0xfc/0x670 [ 772.806336] ? irqentry_exit+0xda/0x580 [ 772.806976] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 772.807772] RIP: 0033:0x7f327cbb2717 [ 772.808323] Code: 73 01 c3 48 8b 0d f9 76 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d c9 76 0d 00 f7 d8 64 89 01 48 [ 772.811337] RSP: 002b:00007ffde7f57d38 EFLAGS: 00000202 ORIG_RAX: 000000000000000b [ 772.812564] RAX: ffffffffffffffda RBX: 00007f327cc9c000 RCX: 00007f327cbb2717 [ 772.813733] RDX: 0000000000000000 RSI: 0000000000400000 RDI: 00007f327c289000 [ 772.814867] RBP: 0000000000421360 R08: 000000000000001a R09: 0000000000000000 [ 772.815991] R10: 0000000000000003 R11: 0000000000000202 R12: 00007ffde7f57d74 [ 772.817121] R13: 00007f327c689010 R14: 0000000000100000 R15: 00007f327c289000 [ 772.818272] </TASK> [ 772.818614] irq event stamp: 0 [ 772.819159] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [ 772.820174] hardirqs last disabled at (0): [<ffffffff82a57ab3>] copy_process+0x19f3/0x6440 [ 772.821511] softirqs last enabled at (0): [<ffffffff82a57b00>] copy_process+0x1a40/0x6440 [ 772.822869] softirqs last disabled at (0): [<0000000000000000>] 0x0 [ 772.823871] ---[ end trace 0000000000000000 ]--- Fix this by using the same check for folio_test_anon() in zap_nonpresent_ptes(). Also add a hmm-test case for this. Link: https://lore.kernel.org/20260501065116.2057242-1-apopple@nvidia.com Fixes: 999dad8 ("mm/shmem: persist uffd-wp bit across zapping for file-backed") Signed-off-by: Alistair Popple <apopple@nvidia.com> Reported-by: Arsen Arsenović <aarsenovic@baylibre.com> Reviewed-by: Balbir Singh <balbirs@nvidia.com> Cc: David Hildenbrand <david@kernel.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Leon Romanovsky <leon@kernel.org> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

…ve pages commit be3f38d upstream. Device private and exclusive entries are only supported for anonymous folios. This condition is tested in __migrate_device_pages() and make_device_exclusive() using folio_test_anon(). However the unmap path tests this assumption using vma_is_anonymous(). This is wrong because whilst anonymous VMAs can only contain folios where folio_test_anon() is true the opposite relation does not hold. A folio for which folio_test_anon() is true does not imply vma_is_anonymous() is true. Such a condition can occur if for example a folio is part of a private filebacked mapping. In this case vma_is_anonymous() is false as the mapping is filebacked, but folio_test_anon() may be true, thus permitting devices to migrate the folio to device private memory. This can lead to the following spurious warnings during process teardown: [ 772.737706] ------------[ cut here ]------------ [ 772.739201] WARNING: mm/memory.c:1754 at unmap_page_range.cold+0x26/0x18a, CPU#17: hmm-tests/2041 [ 772.742050] Modules linked in: test_hmm nvidia_uvm(O) nvidia(O) [ 772.743959] CPU: 17 UID: 0 PID: 2041 Comm: hmm-tests Tainted: G W O 7.0.0+ #387 PREEMPT(full) [ 772.747104] Tainted: [W]=WARN, [O]=OOT_MODULE [ 772.748509] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 [ 772.752117] RIP: 0010:unmap_page_range.cold+0x26/0x18a [ 772.753780] Code: 7e fe ff ff 48 89 4c 24 78 4c 89 44 24 38 e8 f2 ff b1 00 48 8b 4c 24 78 4c 8b 44 24 38 48 8b 44 24 18 48 83 78 48 00 74 04 90 <0f> 0b 90 48 89 ca b8 ff ff 37 00 48 c1 ea 03 48 c1 e0 2a 80 3c 02 [ 772.759602] RSP: 0018:ffff888112607550 EFLAGS: 00010286 [ 772.761310] RAX: ffff88811bbf4dc0 RBX: dffffc0000000000 RCX: ffffea03e9bfffd8 [ 772.763583] RDX: 1ffff1102377e9c1 RSI: 0000000000000008 RDI: ffff88811bbf4e08 [ 772.765914] RBP: 0000000000000006 R08: ffff8881059f7448 R09: ffffed10224c0e68 [ 772.768184] R10: ffff888112607347 R11: 0000000000000001 R12: 0000000000000001 [ 772.770461] R13: ffffea03e9bfffc0 R14: ffff888112607908 R15: ffffea03e9bfffc0 [ 772.772782] FS: 00007f327caa2780(0000) GS:ffff888427b7d000(0000) knlGS:0000000000000000 [ 772.775328] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 772.777187] CR2: 00007f327ca89000 CR3: 00000001994d5000 CR4: 00000000000006f0 [ 772.779135] Call Trace: [ 772.779792] <TASK> [ 772.780317] ? dmirror_interval_invalidate+0x1a3/0x290 [test_hmm] [ 772.781873] ? vm_normal_page_pud+0x2b0/0x2b0 [ 772.782992] ? __rwlock_init+0x150/0x150 [ 772.784006] ? lock_release+0x216/0x2b0 [ 772.785008] ? __mmu_notifier_invalidate_range_start+0x505/0x6e0 [ 772.786522] ? lock_release+0x216/0x2b0 [ 772.787498] ? unmap_single_vma+0xb6/0x210 [ 772.788573] unmap_vmas+0x27d/0x520 [ 772.789506] ? unmap_single_vma+0x210/0x210 [ 772.790607] ? mas_update_gap.part.0+0x620/0x620 [ 772.791834] unmap_region+0x19e/0x350 [ 772.792769] ? remove_vma+0x130/0x130 [ 772.793684] ? mas_alloc_nodes+0x1f2/0x300 [ 772.794730] vms_complete_munmap_vmas+0x8c1/0xe20 [ 772.795926] ? unmap_region+0x350/0x350 [ 772.796917] do_vmi_align_munmap+0x36a/0x4e0 [ 772.798018] ? lock_release+0x216/0x2b0 [ 772.799024] ? vma_shrink+0x620/0x620 [ 772.799983] do_vmi_munmap+0x150/0x2c0 [ 772.800939] __vm_munmap+0x161/0x2c0 [ 772.801872] ? expand_downwards+0xd60/0xd60 [ 772.802948] ? clockevents_program_event+0x1ef/0x540 [ 772.804217] ? lock_release+0x216/0x2b0 [ 772.805158] __x64_sys_munmap+0x59/0x80 [ 772.805776] do_syscall_64+0xfc/0x670 [ 772.806336] ? irqentry_exit+0xda/0x580 [ 772.806976] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 772.807772] RIP: 0033:0x7f327cbb2717 [ 772.808323] Code: 73 01 c3 48 8b 0d f9 76 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d c9 76 0d 00 f7 d8 64 89 01 48 [ 772.811337] RSP: 002b:00007ffde7f57d38 EFLAGS: 00000202 ORIG_RAX: 000000000000000b [ 772.812564] RAX: ffffffffffffffda RBX: 00007f327cc9c000 RCX: 00007f327cbb2717 [ 772.813733] RDX: 0000000000000000 RSI: 0000000000400000 RDI: 00007f327c289000 [ 772.814867] RBP: 0000000000421360 R08: 000000000000001a R09: 0000000000000000 [ 772.815991] R10: 0000000000000003 R11: 0000000000000202 R12: 00007ffde7f57d74 [ 772.817121] R13: 00007f327c689010 R14: 0000000000100000 R15: 00007f327c289000 [ 772.818272] </TASK> [ 772.818614] irq event stamp: 0 [ 772.819159] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [ 772.820174] hardirqs last disabled at (0): [<ffffffff82a57ab3>] copy_process+0x19f3/0x6440 [ 772.821511] softirqs last enabled at (0): [<ffffffff82a57b00>] copy_process+0x1a40/0x6440 [ 772.822869] softirqs last disabled at (0): [<0000000000000000>] 0x0 [ 772.823871] ---[ end trace 0000000000000000 ]--- Fix this by using the same check for folio_test_anon() in zap_nonpresent_ptes(). Also add a hmm-test case for this. Link: https://lore.kernel.org/20260501065116.2057242-1-apopple@nvidia.com Fixes: 999dad8 ("mm/shmem: persist uffd-wp bit across zapping for file-backed") Signed-off-by: Alistair Popple <apopple@nvidia.com> Reported-by: Arsen Arsenović <aarsenovic@baylibre.com> Reviewed-by: Balbir Singh <balbirs@nvidia.com> Cc: David Hildenbrand <david@kernel.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Leon Romanovsky <leon@kernel.org> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvax-r added 2 commits April 23, 2026 01:44

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nvmochs self-requested a review April 23, 2026 14:02

nvmochs approved these changes Apr 23, 2026

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[linux-nvidia-bos] Set LED_HW_PLUGGABLE for NPEM and fix class init ordering issue of CXL/fwctl#387

[linux-nvidia-bos] Set LED_HW_PLUGGABLE for NPEM and fix class init ordering issue of CXL/fwctl#387
nvax-r wants to merge 2 commits into
NVIDIA:26.04_linux-nvidia-bosfrom
nvax-r:cxl_bos_2026_04_23

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nvax-r commented Apr 23, 2026

Description

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Upstream Status

Testing

Build Validation:

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Runtime Testing:

Notes

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✅ Patchscan: No Missing Fixes

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