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+ s390-fix-hugetlb-vmemmap-optimization-crash.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: s390: fix HugeTLB vmemmap optimization crash has been added to the -mm mm-hotfixes-unstable branch. Its filename is s390-fix-hugetlb-vmemmap-optimization-crash.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Luiz Capitulino <luizcap(a)redhat.com> Subject: s390: fix HugeTLB vmemmap optimization crash Date: Tue, 28 Oct 2025 17:15:33 -0400 A reproducible crash occurs when enabling HugeTLB vmemmap optimization (HVO) on s390. The crash and the proposed fix were worked on an s390 KVM guest running on an older hypervisor, as I don't have access to an LPAR. However, the same issue should occur on bare-metal. Reproducer (it may take a few runs to trigger): # sysctl vm.hugetlb_optimize_vmemmap=1 # echo 1 > /proc/sys/vm/nr_hugepages # echo 0 > /proc/sys/vm/nr_hugepages Crash log: [ 52.340369] list_del corruption. prev->next should be 000000d382110008, but was 000000d7116d3880. (prev=000000d7116d3910) [ 52.340420] ------------[ cut here ]------------ [ 52.340424] kernel BUG at lib/list_debug.c:62! [ 52.340566] monitor event: 0040 ilc:2 [#1]SMP [ 52.340573] Modules linked in: ctcm fsm qeth ccwgroup zfcp scsi_transport_fc qdio dasd_fba_mod dasd_eckd_mod dasd_mod xfs ghash_s390 prng des_s390 libdes sha3_512_s390 sha3_256_s390 virtio_net virtio_blk net_failover sha_common failover dm_mirror dm_region_hash dm_log dm_mod paes_s390 crypto_engine pkey_cca pkey_ep11 zcrypt pkey_pckmo pkey aes_s390 [ 52.340606] CPU: 1 UID: 0 PID: 1672 Comm: root-rep2 Kdump: loaded Not tainted 6.18.0-rc3 #1 NONE [ 52.340610] Hardware name: IBM 3931 LA1 400 (KVM/Linux) [ 52.340611] Krnl PSW : 0704c00180000000 0000015710cda7fe (__list_del_entry_valid_or_report+0xfe/0x128) [ 52.340619] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3 [ 52.340622] Krnl GPRS: c0000000ffffefff 0000000100000027 000000000000006d 0000000000000000 [ 52.340623] 000000d7116d35d8 000000d7116d35d0 0000000000000002 000000d7116d39b0 [ 52.340625] 000000d7116d3880 000000d7116d3910 000000d7116d3910 000000d382110008 [ 52.340626] 000003ffac1ccd08 000000d7116d39b0 0000015710cda7fa 000000d7116d37d0 [ 52.340632] Krnl Code: 0000015710cda7ee: c020003e496f larl %r2,00000157114a3acc 0000015710cda7f4: c0e5ffd5280e brasl %r14,000001571077f810 #0000015710cda7fa: af000000 mc 0,0 >0000015710cda7fe: b9040029 lgr %r2,%r9 0000015710cda802: c0e5ffe5e193 brasl %r14,0000015710996b28 0000015710cda808: e34090080004 lg %r4,8(%r9) 0000015710cda80e: b9040059 lgr %r5,%r9 0000015710cda812: b9040038 lgr %r3,%r8 [ 52.340643] Call Trace: [ 52.340645] [<0000015710cda7fe>] __list_del_entry_valid_or_report+0xfe/0x128 [ 52.340649] ([<0000015710cda7fa>] __list_del_entry_valid_or_report+0xfa/0x128) [ 52.340652] [<0000015710a30b2e>] hugetlb_vmemmap_restore_folios+0x96/0x138 [ 52.340655] [<0000015710a268ac>] update_and_free_pages_bulk+0x64/0x150 [ 52.340659] [<0000015710a26f8a>] set_max_huge_pages+0x4ca/0x6f0 [ 52.340662] [<0000015710a273ba>] hugetlb_sysctl_handler_common+0xea/0x120 [ 52.340665] [<0000015710a27484>] hugetlb_sysctl_handler+0x44/0x50 [ 52.340667] [<0000015710b53ffa>] proc_sys_call_handler+0x17a/0x280 [ 52.340672] [<0000015710a90968>] vfs_write+0x2c8/0x3a0 [ 52.340676] [<0000015710a90bd2>] ksys_write+0x72/0x100 [ 52.340679] [<00000157111483a8>] __do_syscall+0x150/0x318 [ 52.340682] [<0000015711153a5e>] system_call+0x6e/0x90 [ 52.340684] Last Breaking-Event-Address: [ 52.340684] [<000001571077f85c>] _printk+0x4c/0x58 [ 52.340690] Kernel panic - not syncing: Fatal exception: panic_on_oops This issue was introduced by commit f13b83fdd996 ("hugetlb: batch TLB flushes when freeing vmemmap"). Before that change, the HVO implementation called flush_tlb_kernel_range() each time a vmemmap PMD split and remapping was performed. The mentioned commit changed this to issue a few flush_tlb_all() calls after performing all remappings. However, on s390, flush_tlb_kernel_range() expands to __tlb_flush_kernel() while flush_tlb_all() is not implemented. As a result, we went from flushing the TLB for every remapping to no flushing at all. This commit fixes this by implementing flush_tlb_all() on s390 as an alias to __tlb_flush_global(). This should cause a flush on all TLB entries on all CPUs as expected by the flush_tlb_all() semantics. Link: https://lkml.kernel.org/r/20251028211533.47694-1-luizcap@redhat.com Fixes: f13b83fdd996 ("hugetlb: batch TLB flushes when freeing vmemmap") Signed-off-by: Luiz Capitulino <luizcap(a)redhat.com> Cc: Alexander Gordeev <agordeev(a)linux.ibm.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar(a)kernel.org> Cc: Christian Borntraeger <borntraeger(a)linux.ibm.com> Cc: David Hildenbrand <david(a)redhat.com> Cc: Gerald Schaefer <gerald.schaefer(a)linux.ibm.com> Cc: Heiko Carstens <hca(a)linux.ibm.com> Cc: Joao Martins <joao.m.martins(a)oracle.com> Cc: Mike Kravetz <mike.kravetz(a)oracle.com> Cc: Oscar Salvador <osalvador(a)suse.de> Cc: Vasily Gorbik <gor(a)linux.ibm.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- arch/s390/include/asm/tlbflush.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/arch/s390/include/asm/tlbflush.h~s390-fix-hugetlb-vmemmap-optimization-crash +++ a/arch/s390/include/asm/tlbflush.h @@ -103,9 +103,13 @@ static inline void __tlb_flush_mm_lazy(s * flush_tlb_range functions need to do the flush. */ #define flush_tlb() do { } while (0) -#define flush_tlb_all() do { } while (0) #define flush_tlb_page(vma, addr) do { } while (0) +static inline void flush_tlb_all(void) +{ + __tlb_flush_global(); +} + static inline void flush_tlb_mm(struct mm_struct *mm) { __tlb_flush_mm_lazy(mm); _ Patches currently in -mm which might be from luizcap(a)redhat.com are s390-fix-hugetlb-vmemmap-optimization-crash.patch

3 weeks, 2 days

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[PATCH] video: valkyriefb: Fix reference count leak in valkyriefb_init

by Miaoqian Lin

The of_find_node_by_name() function returns a device tree node with its reference count incremented. The caller is responsible for calling of_node_put() to release this reference when done. Found via static analysis. Fixes: cc5d0189b9ba ("[PATCH] powerpc: Remove device_node addrs/n_addr") Cc: stable(a)vger.kernel.org Signed-off-by: Miaoqian Lin <linmq006(a)gmail.com> --- drivers/video/fbdev/valkyriefb.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/video/fbdev/valkyriefb.c b/drivers/video/fbdev/valkyriefb.c index 91d070ef6989..6ff059ee1694 100644 --- a/drivers/video/fbdev/valkyriefb.c +++ b/drivers/video/fbdev/valkyriefb.c @@ -329,11 +329,13 @@ static int __init valkyriefb_init(void) if (of_address_to_resource(dp, 0, &r)) { printk(KERN_ERR "can't find address for valkyrie\n"); + of_node_put(dp); return 0; } frame_buffer_phys = r.start; cmap_regs_phys = r.start + 0x304000; + of_node_put(dp); } #endif /* ppc (!CONFIG_MAC) */ -- 2.39.5 (Apple Git-154)

3 weeks, 2 days

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+ codetag-debug-handle-existing-codetag_empty-in-mark_objexts_empty-for-slabobj_ext.patch added to mm-new branch

by Andrew Morton

The patch titled Subject: codetag: debug: handle existing CODETAG_EMPTY in mark_objexts_empty for slabobj_ext has been added to the -mm mm-new branch. Its filename is codetag-debug-handle-existing-codetag_empty-in-mark_objexts_empty-for-slabobj_ext.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Hao Ge <gehao(a)kylinos.cn> Subject: codetag: debug: handle existing CODETAG_EMPTY in mark_objexts_empty for slabobj_ext Date: Mon, 27 Oct 2025 16:52:14 +0800 Even though obj_exts was created with the __GFP_NO_OBJ_EXT flag, objects in the same slab may have their extensions allocated via alloc_slab_obj_exts, and handle_failed_objexts_alloc may be called within alloc_slab_obj_exts to set their codetag to CODETAG_EMPTY. Therefore, both NULL and CODETAG_EMPTY are valid for the codetag of slabobj_ext, as we do not need to re-set it to CODETAG_EMPTY if it is already CODETAG_EMPTY. It also resolves the warning triggered when the codetag is CODETAG_EMPTY during slab freeing. This issue also occurred during our memory stress testing. The possibility of its occurrence should be as follows: When a slab allocates a slabobj_ext, the slab to which this slabobj_ext belongs may have already allocated its own slabobj_ext and called handle_failed_objexts_alloc. That is to say, the codetag of this slabobj_ext has been set to CODETAG_EMPTY. To quickly detect this WARN, I modified the code from:WARN_ON(slab_exts[offs].ref.ct) to WARN_ON(slab_exts[offs].ref.ct == 1); We then obtained this message: [21630.898561] ------------[ cut here ]------------ [21630.898596] kernel BUG at mm/slub.c:2050! [21630.898611] Internal error: Oops - BUG: 00000000f2000800 [#1] SMP [21630.900372] Modules linked in: squashfs isofs vfio_iommu_type1 vhost_vsock vfio vhost_net vmw_vsock_virtio_transport_common vhost tap vhost_iotlb iommufd vsock binfmt_misc nfsv3 nfs_acl nfs lockd grace netfs tls rds dns_resolver tun brd overlay ntfs3 exfat btrfs blake2b_generic xor xor_neon raid6_pq loop sctp ip6_udp_tunnel udp_tunnel nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables rfkill ip_set sunrpc vfat fat joydev sg sch_fq_codel nfnetlink virtio_gpu sr_mod cdrom drm_client_lib virtio_dma_buf drm_shmem_helper drm_kms_helper drm ghash_ce backlight virtio_net virtio_blk virtio_scsi net_failover virtio_console failover virtio_mmio dm_mirror dm_region_hash dm_log dm_multipath dm_mod fuse i2c_dev virtio_pci virtio_pci_legacy_dev virtio_pci_modern_dev virtio virtio_ring autofs4 aes_neon_bs aes_ce_blk [last unloaded: hwpoison_inject] [21630.909177] CPU: 3 UID: 0 PID: 3787 Comm: kylin-process-m Kdump: loaded Tainted: G�� W�� 6.18.0-rc1+ #74 PREEMPT(voluntary) [21630.910495] Tainted: [W]=WARN [21630.910867] Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022 [21630.911625] pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [21630.912392] pc : __free_slab+0x228/0x250 [21630.912868] lr : __free_slab+0x18c/0x250[21630.913334] sp : ffff8000a02f73e0 [21630.913830] x29: ffff8000a02f73e0 x28: fffffdffc43fc800 x27: ffff0000c0011c40 [21630.914677] x26: ffff0000c000cac0 x25: ffff00010fe5e5f0 x24: ffff000102199b40 [21630.915469] x23: 0000000000000003 x22: 0000000000000003 x21: ffff0000c0011c40 [21630.916259] x20: fffffdffc4086600 x19: fffffdffc43fc800 x18: 0000000000000000 [21630.917048] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 [21630.917837] x14: 0000000000000000 x13: 0000000000000000 x12: ffff70001405ee66 [21630.918640] x11: 1ffff0001405ee65 x10: ffff70001405ee65 x9 : ffff800080a295dc [21630.919442] x8 : ffff8000a02f7330 x7 : 0000000000000000 x6 : 0000000000003000 [21630.920232] x5 : 0000000024924925 x4 : 0000000000000001 x3 : 0000000000000007 [21630.921021] x2 : 0000000000001b40 x1 : 000000000000001f x0 : 0000000000000001 [21630.921810] Call trace: [21630.922130]�� __free_slab+0x228/0x250 (P) [21630.922669]�� free_slab+0x38/0x118 [21630.923079]�� free_to_partial_list+0x1d4/0x340 [21630.923591]�� __slab_free+0x24c/0x348 [21630.924024]�� ___cache_free+0xf0/0x110 [21630.924468]�� qlist_free_all+0x78/0x130 [21630.924922]�� kasan_quarantine_reduce+0x114/0x148 [21630.925525]�� __kasan_slab_alloc+0x7c/0xb0 [21630.926006]�� kmem_cache_alloc_noprof+0x164/0x5c8 [21630.926699]�� __alloc_object+0x44/0x1f8 [21630.927153]�� __create_object+0x34/0xc8 [21630.927604]�� kmemleak_alloc+0xb8/0xd8 [21630.928052]�� kmem_cache_alloc_noprof+0x368/0x5c8 [21630.928606]�� getname_flags.part.0+0xa4/0x610 [21630.929112]�� getname_flags+0x80/0xd8 [21630.929557]�� vfs_fstatat+0xc8/0xe0 [21630.929975]�� __do_sys_newfstatat+0xa0/0x100 [21630.930469]�� __arm64_sys_newfstatat+0x90/0xd8 [21630.931046]�� invoke_syscall+0xd4/0x258 [21630.931685]�� el0_svc_common.constprop.0+0xb4/0x240 [21630.932467]�� do_el0_svc+0x48/0x68 [21630.932972]�� el0_svc+0x40/0xe0 [21630.933472]�� el0t_64_sync_handler+0xa0/0xe8 [21630.934151]�� el0t_64_sync+0x1ac/0x1b0 [21630.934923] Code: aa1803e0 97ffef2b a9446bf9 17ffff9c (d4210000) [21630.936461] SMP: stopping secondary CPUs [21630.939550] Starting crashdump kernel... [21630.940108] Bye! Link: https://lkml.kernel.org/r/20251027085214.184672-1-hao.ge@linux.dev Fixes: 09c46563ff6d ("codetag: debug: introduce OBJEXTS_ALLOC_FAIL to mark failed slab_ext allocations") Signed-off-by: Hao Ge <gehao(a)kylinos.cn> Cc: Suren Baghdasaryan <surenb(a)google.com> Cc: Christoph Lameter (Ampere) <cl(a)gentwo.org> Cc: David Rientjes <rientjes(a)google.com> Cc: Roman Gushchin <roman.gushchin(a)linux.dev> Cc: Shakeel Butt <shakeel.butt(a)linux.dev> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/slub.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/mm/slub.c~codetag-debug-handle-existing-codetag_empty-in-mark_objexts_empty-for-slabobj_ext +++ a/mm/slub.c @@ -2046,7 +2046,17 @@ static inline void mark_objexts_empty(st if (slab_exts) { unsigned int offs = obj_to_index(obj_exts_slab->slab_cache, obj_exts_slab, obj_exts); - /* codetag should be NULL */ + + /* + * codetag should be either NULL or CODETAG_EMPTY. + * When the same slab calls handle_failed_objexts_alloc, + * it will set us to CODETAG_EMPTY. + * + * If codetag is already CODETAG_EMPTY, no action is needed here. + */ + if (unlikely(is_codetag_empty(&slab_exts[offs].ref))) + return; + WARN_ON(slab_exts[offs].ref.ct); set_codetag_empty(&slab_exts[offs].ref); } _ Patches currently in -mm which might be from gehao(a)kylinos.cn are codetag-debug-handle-existing-codetag_empty-in-mark_objexts_empty-for-slabobj_ext.patch

3 weeks, 2 days

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+ mm-mm_init-fix-hash-table-order-logging-in-alloc_large_system_hash.patch added to mm-hotfixes-unstable branch

by Andrew Morton

The patch titled Subject: mm/mm_init: fix hash table order logging in alloc_large_system_hash() has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-mm_init-fix-hash-table-order-logging-in-alloc_large_system_hash.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: "Isaac J. Manjarres" <isaacmanjarres(a)google.com> Subject: mm/mm_init: fix hash table order logging in alloc_large_system_hash() Date: Tue, 28 Oct 2025 12:10:12 -0700 When emitting the order of the allocation for a hash table, alloc_large_system_hash() unconditionally subtracts PAGE_SHIFT from log base 2 of the allocation size. This is not correct if the allocation size is smaller than a page, and yields a negative value for the order as seen below: TCP established hash table entries: 32 (order: -4, 256 bytes, linear) TCP bind hash table entries: 32 (order: -2, 1024 bytes, linear) Use get_order() to compute the order when emitting the hash table information to correctly handle cases where the allocation size is smaller than a page: TCP established hash table entries: 32 (order: 0, 256 bytes, linear) TCP bind hash table entries: 32 (order: 0, 1024 bytes, linear) Link: https://lkml.kernel.org/r/20251028191020.413002-1-isaacmanjarres@google.com Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Isaac J. Manjarres <isaacmanjarres(a)google.com> Cc: Mike Rapoport <rppt(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/mm_init.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/mm_init.c~mm-mm_init-fix-hash-table-order-logging-in-alloc_large_system_hash +++ a/mm/mm_init.c @@ -2469,7 +2469,7 @@ void *__init alloc_large_system_hash(con panic("Failed to allocate %s hash table\n", tablename); pr_info("%s hash table entries: %ld (order: %d, %lu bytes, %s)\n", - tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size, + tablename, 1UL << log2qty, get_order(size), size, virt ? (huge ? "vmalloc hugepage" : "vmalloc") : "linear"); if (_hash_shift) _ Patches currently in -mm which might be from isaacmanjarres(a)google.com are mm-mm_init-fix-hash-table-order-logging-in-alloc_large_system_hash.patch

3 weeks, 2 days

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FAILED: patch "[PATCH] x86/resctrl: Fix miscount of bandwidth event when" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 15292f1b4c55a3a7c940dbcb6cb8793871ed3d92 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102058-citadel-crinkly-125f@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 15292f1b4c55a3a7c940dbcb6cb8793871ed3d92 Mon Sep 17 00:00:00 2001 From: Babu Moger <babu.moger(a)amd.com> Date: Fri, 10 Oct 2025 12:08:35 -0500 Subject: [PATCH] x86/resctrl: Fix miscount of bandwidth event when reactivating previously unavailable RMID Users can create as many monitoring groups as the number of RMIDs supported by the hardware. However, on AMD systems, only a limited number of RMIDs are guaranteed to be actively tracked by the hardware. RMIDs that exceed this limit are placed in an "Unavailable" state. When a bandwidth counter is read for such an RMID, the hardware sets MSR_IA32_QM_CTR.Unavailable (bit 62). When such an RMID starts being tracked again the hardware counter is reset to zero. MSR_IA32_QM_CTR.Unavailable remains set on first read after tracking re-starts and is clear on all subsequent reads as long as the RMID is tracked. resctrl miscounts the bandwidth events after an RMID transitions from the "Unavailable" state back to being tracked. This happens because when the hardware starts counting again after resetting the counter to zero, resctrl in turn compares the new count against the counter value stored from the previous time the RMID was tracked. This results in resctrl computing an event value that is either undercounting (when new counter is more than stored counter) or a mistaken overflow (when new counter is less than stored counter). Reset the stored value (arch_mbm_state::prev_msr) of MSR_IA32_QM_CTR to zero whenever the RMID is in the "Unavailable" state to ensure accurate counting after the RMID resets to zero when it starts to be tracked again. Example scenario that results in mistaken overflow ================================================== 1. The resctrl filesystem is mounted, and a task is assigned to a monitoring group. $mount -t resctrl resctrl /sys/fs/resctrl $mkdir /sys/fs/resctrl/mon_groups/test1/ $echo 1234 > /sys/fs/resctrl/mon_groups/test1/tasks $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes 21323 <- Total bytes on domain 0 "Unavailable" <- Total bytes on domain 1 Task is running on domain 0. Counter on domain 1 is "Unavailable". 2. The task runs on domain 0 for a while and then moves to domain 1. The counter starts incrementing on domain 1. $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes 7345357 <- Total bytes on domain 0 4545 <- Total bytes on domain 1 3. At some point, the RMID in domain 0 transitions to the "Unavailable" state because the task is no longer executing in that domain. $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes "Unavailable" <- Total bytes on domain 0 434341 <- Total bytes on domain 1 4. Since the task continues to migrate between domains, it may eventually return to domain 0. $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes 17592178699059 <- Overflow on domain 0 3232332 <- Total bytes on domain 1 In this case, the RMID on domain 0 transitions from "Unavailable" state to active state. The hardware sets MSR_IA32_QM_CTR.Unavailable (bit 62) when the counter is read and begins tracking the RMID counting from 0. Subsequent reads succeed but return a value smaller than the previously saved MSR value (7345357). Consequently, the resctrl's overflow logic is triggered, it compares the previous value (7345357) with the new, smaller value and incorrectly interprets this as a counter overflow, adding a large delta. In reality, this is a false positive: the counter did not overflow but was simply reset when the RMID transitioned from "Unavailable" back to active state. Here is the text from APM [1] available from [2]. "In PQOS Version 2.0 or higher, the MBM hardware will set the U bit on the first QM_CTR read when it begins tracking an RMID that it was not previously tracking. The U bit will be zero for all subsequent reads from that RMID while it is still tracked by the hardware. Therefore, a QM_CTR read with the U bit set when that RMID is in use by a processor can be considered 0 when calculating the difference with a subsequent read." [1] AMD64 Architecture Programmer's Manual Volume 2: System Programming Publication # 24593 Revision 3.41 section 19.3.3 Monitoring L3 Memory Bandwidth (MBM). [ bp: Split commit message into smaller paragraph chunks for better consumption. ] Fixes: 4d05bf71f157d ("x86/resctrl: Introduce AMD QOS feature") Signed-off-by: Babu Moger <babu.moger(a)amd.com> Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre(a)intel.com> Tested-by: Reinette Chatre <reinette.chatre(a)intel.com> Cc: stable(a)vger.kernel.org # needs adjustments for <= v6.17 Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 # [2] diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c index c8945610d455..2cd25a0d4637 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -242,7 +242,9 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_mon_domain *d, u32 unused, u32 rmid, enum resctrl_event_id eventid, u64 *val, void *ignored) { + struct rdt_hw_mon_domain *hw_dom = resctrl_to_arch_mon_dom(d); int cpu = cpumask_any(&d->hdr.cpu_mask); + struct arch_mbm_state *am; u64 msr_val; u32 prmid; int ret; @@ -251,12 +253,16 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_mon_domain *d, prmid = logical_rmid_to_physical_rmid(cpu, rmid); ret = __rmid_read_phys(prmid, eventid, &msr_val); - if (ret) - return ret; - *val = get_corrected_val(r, d, rmid, eventid, msr_val); + if (!ret) { + *val = get_corrected_val(r, d, rmid, eventid, msr_val); + } else if (ret == -EINVAL) { + am = get_arch_mbm_state(hw_dom, rmid, eventid); + if (am) + am->prev_msr = 0; + } - return 0; + return ret; } static int __cntr_id_read(u32 cntr_id, u64 *val)

3 weeks, 2 days

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[tip: x86/urgent] x86/fpu: Ensure XFD state on signal delivery

by tip-bot2 for Chang S. Bae

The following commit has been merged into the x86/urgent branch of tip: Commit-ID: 388eff894d6bc5f921e9bfff0e4b0ab2684a96e9 Gitweb: https://git.kernel.org/tip/388eff894d6bc5f921e9bfff0e4b0ab2684a96e9 Author: Chang S. Bae <chang.seok.bae(a)intel.com> AuthorDate: Mon, 09 Jun 2025 17:16:59 -07:00 Committer: Dave Hansen <dave.hansen(a)linux.intel.com> CommitterDate: Tue, 28 Oct 2025 12:10:59 -07:00 x86/fpu: Ensure XFD state on signal delivery Sean reported [1] the following splat when running KVM tests: WARNING: CPU: 232 PID: 15391 at xfd_validate_state+0x65/0x70 Call Trace: <TASK> fpu__clear_user_states+0x9c/0x100 arch_do_signal_or_restart+0x142/0x210 exit_to_user_mode_loop+0x55/0x100 do_syscall_64+0x205/0x2c0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Chao further identified [2] a reproducible scenario involving signal delivery: a non-AMX task is preempted by an AMX-enabled task which modifies the XFD MSR. When the non-AMX task resumes and reloads XSTATE with init values, a warning is triggered due to a mismatch between fpstate::xfd and the CPU's current XFD state. fpu__clear_user_states() does not currently re-synchronize the XFD state after such preemption. Invoke xfd_update_state() which detects and corrects the mismatch if there is a dynamic feature. This also benefits the sigreturn path, as fpu__restore_sig() may call fpu__clear_user_states() when the sigframe is inaccessible. [ dhansen: minor changelog munging ] Closes: https://lore.kernel.org/lkml/aDCo_SczQOUaB2rS@google.com [1] Fixes: 672365477ae8a ("x86/fpu: Update XFD state where required") Reported-by: Sean Christopherson <seanjc(a)google.com> Signed-off-by: Chang S. Bae <chang.seok.bae(a)intel.com> Signed-off-by: Dave Hansen <dave.hansen(a)linux.intel.com> Reviewed-by: Chao Gao <chao.gao(a)intel.com> Tested-by: Chao Gao <chao.gao(a)intel.com> Link: https://lore.kernel.org/all/aDWbctO%2FRfTGiCg3@intel.com [2] Cc:stable@vger.kernel.org Link: https://patch.msgid.link/20250610001700.4097-1-chang.seok.bae%40intel.com --- arch/x86/kernel/fpu/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 1f71cc1..e88eacb 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -825,6 +825,9 @@ void fpu__clear_user_states(struct fpu *fpu) !fpregs_state_valid(fpu, smp_processor_id())) os_xrstor_supervisor(fpu->fpstate); + /* Ensure XFD state is in sync before reloading XSTATE */ + xfd_update_state(fpu->fpstate); + /* Reset user states in registers. */ restore_fpregs_from_init_fpstate(XFEATURE_MASK_USER_RESTORE);

3 weeks, 2 days

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FAILED: patch "[PATCH] x86/resctrl: Fix miscount of bandwidth event when" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 15292f1b4c55a3a7c940dbcb6cb8793871ed3d92 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102056-qualify-unopposed-be08@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 15292f1b4c55a3a7c940dbcb6cb8793871ed3d92 Mon Sep 17 00:00:00 2001 From: Babu Moger <babu.moger(a)amd.com> Date: Fri, 10 Oct 2025 12:08:35 -0500 Subject: [PATCH] x86/resctrl: Fix miscount of bandwidth event when reactivating previously unavailable RMID Users can create as many monitoring groups as the number of RMIDs supported by the hardware. However, on AMD systems, only a limited number of RMIDs are guaranteed to be actively tracked by the hardware. RMIDs that exceed this limit are placed in an "Unavailable" state. When a bandwidth counter is read for such an RMID, the hardware sets MSR_IA32_QM_CTR.Unavailable (bit 62). When such an RMID starts being tracked again the hardware counter is reset to zero. MSR_IA32_QM_CTR.Unavailable remains set on first read after tracking re-starts and is clear on all subsequent reads as long as the RMID is tracked. resctrl miscounts the bandwidth events after an RMID transitions from the "Unavailable" state back to being tracked. This happens because when the hardware starts counting again after resetting the counter to zero, resctrl in turn compares the new count against the counter value stored from the previous time the RMID was tracked. This results in resctrl computing an event value that is either undercounting (when new counter is more than stored counter) or a mistaken overflow (when new counter is less than stored counter). Reset the stored value (arch_mbm_state::prev_msr) of MSR_IA32_QM_CTR to zero whenever the RMID is in the "Unavailable" state to ensure accurate counting after the RMID resets to zero when it starts to be tracked again. Example scenario that results in mistaken overflow ================================================== 1. The resctrl filesystem is mounted, and a task is assigned to a monitoring group. $mount -t resctrl resctrl /sys/fs/resctrl $mkdir /sys/fs/resctrl/mon_groups/test1/ $echo 1234 > /sys/fs/resctrl/mon_groups/test1/tasks $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes 21323 <- Total bytes on domain 0 "Unavailable" <- Total bytes on domain 1 Task is running on domain 0. Counter on domain 1 is "Unavailable". 2. The task runs on domain 0 for a while and then moves to domain 1. The counter starts incrementing on domain 1. $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes 7345357 <- Total bytes on domain 0 4545 <- Total bytes on domain 1 3. At some point, the RMID in domain 0 transitions to the "Unavailable" state because the task is no longer executing in that domain. $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes "Unavailable" <- Total bytes on domain 0 434341 <- Total bytes on domain 1 4. Since the task continues to migrate between domains, it may eventually return to domain 0. $cat /sys/fs/resctrl/mon_groups/test1/mon_data/mon_L3_*/mbm_total_bytes 17592178699059 <- Overflow on domain 0 3232332 <- Total bytes on domain 1 In this case, the RMID on domain 0 transitions from "Unavailable" state to active state. The hardware sets MSR_IA32_QM_CTR.Unavailable (bit 62) when the counter is read and begins tracking the RMID counting from 0. Subsequent reads succeed but return a value smaller than the previously saved MSR value (7345357). Consequently, the resctrl's overflow logic is triggered, it compares the previous value (7345357) with the new, smaller value and incorrectly interprets this as a counter overflow, adding a large delta. In reality, this is a false positive: the counter did not overflow but was simply reset when the RMID transitioned from "Unavailable" back to active state. Here is the text from APM [1] available from [2]. "In PQOS Version 2.0 or higher, the MBM hardware will set the U bit on the first QM_CTR read when it begins tracking an RMID that it was not previously tracking. The U bit will be zero for all subsequent reads from that RMID while it is still tracked by the hardware. Therefore, a QM_CTR read with the U bit set when that RMID is in use by a processor can be considered 0 when calculating the difference with a subsequent read." [1] AMD64 Architecture Programmer's Manual Volume 2: System Programming Publication # 24593 Revision 3.41 section 19.3.3 Monitoring L3 Memory Bandwidth (MBM). [ bp: Split commit message into smaller paragraph chunks for better consumption. ] Fixes: 4d05bf71f157d ("x86/resctrl: Introduce AMD QOS feature") Signed-off-by: Babu Moger <babu.moger(a)amd.com> Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre(a)intel.com> Tested-by: Reinette Chatre <reinette.chatre(a)intel.com> Cc: stable(a)vger.kernel.org # needs adjustments for <= v6.17 Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 # [2] diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c index c8945610d455..2cd25a0d4637 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -242,7 +242,9 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_mon_domain *d, u32 unused, u32 rmid, enum resctrl_event_id eventid, u64 *val, void *ignored) { + struct rdt_hw_mon_domain *hw_dom = resctrl_to_arch_mon_dom(d); int cpu = cpumask_any(&d->hdr.cpu_mask); + struct arch_mbm_state *am; u64 msr_val; u32 prmid; int ret; @@ -251,12 +253,16 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_mon_domain *d, prmid = logical_rmid_to_physical_rmid(cpu, rmid); ret = __rmid_read_phys(prmid, eventid, &msr_val); - if (ret) - return ret; - *val = get_corrected_val(r, d, rmid, eventid, msr_val); + if (!ret) { + *val = get_corrected_val(r, d, rmid, eventid, msr_val); + } else if (ret == -EINVAL) { + am = get_arch_mbm_state(hw_dom, rmid, eventid); + if (am) + am->prev_msr = 0; + } - return 0; + return ret; } static int __cntr_id_read(u32 cntr_id, u64 *val)

3 weeks, 2 days

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[PATCH AUTOSEL 6.17-5.4] ACPI: property: Return present device nodes only on fwnode interface

by Sasha Levin

From: Sakari Ailus <sakari.ailus(a)linux.intel.com> [ Upstream commit d9f866b2bb3eec38b3734f1fed325ec7c55ccdfa ] fwnode_graph_get_next_subnode() may return fwnode backed by ACPI device nodes and there has been no check these devices are present in the system, unlike there has been on fwnode OF backend. In order to provide consistent behaviour towards callers, add a check for device presence by introducing a new function acpi_get_next_present_subnode(), used as the get_next_child_node() fwnode operation that also checks device node presence. Signed-off-by: Sakari Ailus <sakari.ailus(a)linux.intel.com> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas(a)ideasonboard.com> Reviewed-by: Jonathan Cameron <jonathan.cameron(a)huawei.com> Link: https://patch.msgid.link/20251001102636.1272722-2-sakari.ailus@linux.intel.… [ rjw: Kerneldoc comment and changelog edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki(a)intel.com> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- LLM Generated explanations, may be completely bogus: YES – this change fixes a real behavioural bug in the ACPI fwnode backend and should go to stable. - `drivers/acpi/property.c:1375` adds `acpi_get_next_present_subnode()` so `.get_next_child_node` skips ACPI child devices whose `_STA` says they are absent (`acpi_device_is_present()`), while still returning data subnodes unchanged. - The new helper is now wired into the ACPI fwnode ops (`drivers/acpi/property.c:1731`), making generic helpers such as `fwnode_get_next_child_node()` and macros like `fwnode_for_each_child_node` (`include/linux/property.h:167`) behave the same as the OF backend, which already filtered unavailable children via `of_get_next_available_child()` (`drivers/of/property.c:1070`). - Several core helpers assume disabled endpoints never surface: e.g. `fwnode_graph_get_endpoint_by_id()` in `drivers/base/property.c:1286` promises to hide endpoints on disabled devices, and higher layers such as `v4l2_fwnode_reference_get_int_prop()` (`drivers/media/v4l2-core/v4l2-fwnode.c:1064`) iterate child nodes without rechecking availability. On ACPI systems today they still see powered-off devices, leading to asynchronous notifiers that wait forever for hardware that can’t appear, or to bogus graph enumerations. This patch closes that gap. Risk is low: it only suppresses ACPI device nodes already known to be absent, aligns behaviour with DT userspace expectations, and leaves data nodes untouched. No extra dependencies are required, so the fix is self- contained and appropriate for stable backporting. Suggest running existing ACPI graph users (media/typec drivers) after backport to confirm no regressions. drivers/acpi/property.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c index c086786fe84cb..d74678f0ba4af 100644 --- a/drivers/acpi/property.c +++ b/drivers/acpi/property.c @@ -1357,6 +1357,28 @@ struct fwnode_handle *acpi_get_next_subnode(const struct fwnode_handle *fwnode, return NULL; } +/* + * acpi_get_next_present_subnode - Return the next present child node handle + * @fwnode: Firmware node to find the next child node for. + * @child: Handle to one of the device's child nodes or a null handle. + * + * Like acpi_get_next_subnode(), but the device nodes returned by + * acpi_get_next_present_subnode() are guaranteed to be present. + * + * Returns: The fwnode handle of the next present sub-node. + */ +static struct fwnode_handle * +acpi_get_next_present_subnode(const struct fwnode_handle *fwnode, + struct fwnode_handle *child) +{ + do { + child = acpi_get_next_subnode(fwnode, child); + } while (is_acpi_device_node(child) && + !acpi_device_is_present(to_acpi_device_node(child))); + + return child; +} + /** * acpi_node_get_parent - Return parent fwnode of this fwnode * @fwnode: Firmware node whose parent to get @@ -1701,7 +1723,7 @@ static int acpi_fwnode_irq_get(const struct fwnode_handle *fwnode, .property_read_string_array = \ acpi_fwnode_property_read_string_array, \ .get_parent = acpi_node_get_parent, \ - .get_next_child_node = acpi_get_next_subnode, \ + .get_next_child_node = acpi_get_next_present_subnode, \ .get_named_child_node = acpi_fwnode_get_named_child_node, \ .get_name = acpi_fwnode_get_name, \ .get_name_prefix = acpi_fwnode_get_name_prefix, \ -- 2.51.0

3 weeks, 2 days

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[PATCH] x86/fpu: Ensure XFD state on signal delivery

by Chang S. Bae

Sean reported [1] the following splat when running KVM tests: WARNING: CPU: 232 PID: 15391 at xfd_validate_state+0x65/0x70 Call Trace: <TASK> fpu__clear_user_states+0x9c/0x100 arch_do_signal_or_restart+0x142/0x210 exit_to_user_mode_loop+0x55/0x100 do_syscall_64+0x205/0x2c0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Chao further identified [2] a reproducible scenarios involving signal delivery: a non-AMX task is preempted by an AMX-enabled task which modifies the XFD MSR. When the non-AMX task resumes and reloads XSTATE with init values, a warning is triggered due to a mismatch between fpstate::xfd and the CPU's current XFD state. fpu__clear_user_states() does not currently re-synchronize the XFD state after such preemption. Invoke xfd_update_state() which detects and corrects the mismatch if the dynamic feature is enabled. This also benefits the sigreturn path, as fpu__restore_sig() may call fpu__clear_user_states() when the sigframe is inaccessible. Fixes: 672365477ae8a ("x86/fpu: Update XFD state where required") Reported-by: Sean Christopherson <seanjc(a)google.com> Closes: https://lore.kernel.org/lkml/aDCo_SczQOUaB2rS@google.com [1] Tested-by: Chao Gao <chao.gao(a)intel.com> Signed-off-by: Chang S. Bae <chang.seok.bae(a)intel.com> Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/all/aDWbctO%2FRfTGiCg3@intel.com [2] --- arch/x86/kernel/fpu/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index ea138583dd92..5fa782a2ae7c 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -800,6 +800,9 @@ void fpu__clear_user_states(struct fpu *fpu) !fpregs_state_valid(fpu, smp_processor_id())) os_xrstor_supervisor(fpu->fpstate); + /* Ensure XFD state is in sync before reloading XSTATE */ + xfd_update_state(fpu->fpstate); + /* Reset user states in registers. */ restore_fpregs_from_init_fpstate(XFEATURE_MASK_USER_RESTORE); -- 2.48.1

3 weeks, 2 days

3
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[PATCH] regmap: irq: Correct documentation of wake_invert flag

by Shawn Guo

From: Shawn Guo <shawnguo(a)kernel.org> Per commit 9442490a0286 ("regmap: irq: Support wake IRQ mask inversion") the wake_invert flag is to support enable register, so cleared bits are wake disabled. Fixes: 68622bdfefb9 ("regmap: irq: document mask/wake_invert flags") Cc: stable(a)vger.kernel.org Signed-off-by: Shawn Guo <shawnguo(a)kernel.org> --- include/linux/regmap.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/regmap.h b/include/linux/regmap.h index 4e1ac1fbcec4..55343795644b 100644 --- a/include/linux/regmap.h +++ b/include/linux/regmap.h @@ -1643,7 +1643,7 @@ struct regmap_irq_chip_data; * @status_invert: Inverted status register: cleared bits are active interrupts. * @status_is_level: Status register is actuall signal level: Xor status * register with previous value to get active interrupts. - * @wake_invert: Inverted wake register: cleared bits are wake enabled. + * @wake_invert: Inverted wake register: cleared bits are wake disabled. * @type_in_mask: Use the mask registers for controlling irq type. Use this if * the hardware provides separate bits for rising/falling edge * or low/high level interrupts and they should be combined into -- 2.43.0

3 weeks, 2 days

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