kernel/arch/arm64/mm, branch linux-rolling-stable

arm64: contpte: fix set_access_flags() no-op check for SMMU/ATS faults

2026-03-19T15:15:20Z

commit 97c5550b763171dbef61e6239cab372b9f9cd4a2 upstream. contpte_ptep_set_access_flags() compared the gathered ptep_get() value against the requested entry to detect no-ops. ptep_get() ORs AF/dirty from all sub-PTEs in the CONT block, so a dirty sibling can make the target appear already-dirty. When the gathered value matches entry, the function returns 0 even though the target sub-PTE still has PTE_RDONLY set in hardware. For a CPU with FEAT_HAFDBS this gathered view is fine, since hardware may set AF/dirty on any sub-PTE and CPU TLB behavior is effectively gathered across the CONT range. But page-table walkers that evaluate each descriptor individually (e.g. a CPU without DBM support, or an SMMU without HTTU, or with HA/HD disabled in CD.TCR) can keep faulting on the unchanged target sub-PTE, causing an infinite fault loop. Gathering can therefore cause false no-ops when only a sibling has been updated: - write faults: target still has PTE_RDONLY (needs PTE_RDONLY cleared) - read faults: target still lacks PTE_AF Fix by checking each sub-PTE against the requested AF/dirty/write state (the same bits consumed by __ptep_set_access_flags()), using raw per-PTE values rather than the gathered ptep_get() view, before returning no-op. Keep using the raw target PTE for the write-bit unfold decision. Per Arm ARM (DDI 0487) D8.7.1 ("The Contiguous bit"), any sub-PTE in a CONT range may become the effective cached translation and software must maintain consistent attributes across the range. Fixes: 4602e5757bcc ("arm64/mm: wire up PTE_CONT for user mappings") Cc: Ryan Roberts Cc: Catalin Marinas Cc: Will Deacon Cc: Jason Gunthorpe Cc: John Hubbard Cc: Zi Yan Cc: Breno Leitao Cc: stable@vger.kernel.org Reviewed-by: Alistair Popple Reviewed-by: James Houghton Reviewed-by: Ryan Roberts Reviewed-by: Catalin Marinas Tested-by: Breno Leitao Signed-off-by: Piotr Jaroszynski Acked-by: Balbir Singh Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman

arm64: gcs: Honour mprotect(PROT_NONE) on shadow stack mappings

2026-03-19T15:15:14Z

commit 47a8aad135ac1aed04b7b0c0a8157fd208075827 upstream. vm_get_page_prot() short-circuits the protection_map[] lookup for a VM_SHADOW_STACK mapping since it uses a different PIE index from the typical read/write/exec permissions. However, the side effect is that it also ignores mprotect(PROT_NONE) by creating an accessible PTE. Special-case the !(vm_flags & VM_ACCESS_FLAGS) flags to use the protection_map[VM_NONE] permissions instead. No GCS attributes are required for an inaccessible PTE. Signed-off-by: Catalin Marinas Fixes: 6497b66ba694 ("arm64/mm: Map pages for guarded control stack") Cc: stable@vger.kernel.org Cc: Mark Brown Cc: Will Deacon Cc: David Hildenbrand Reviewed-by: David Hildenbrand (Arm) Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman

arm64: gcs: Do not set PTE_SHARED on GCS mappings if FEAT_LPA2 is enabled

2026-03-12T11:09:35Z

commit 8a85b3131225a8c8143ba2ae29c0eef8c1f9117f upstream. When FEAT_LPA2 is enabled, bits 8-9 of the PTE replace the shareability attribute with bits 50-51 of the output address. The _PAGE_GCS{,_RO} definitions include the PTE_SHARED bits as 0b11 (this matches the other _PAGE_* definitions) but using this macro directly leads to the following panic when enabling GCS on a system/model with LPA2: Unable to handle kernel paging request at virtual address fffff1ffc32d8008 Mem abort info: ESR = 0x0000000096000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault Data abort info: ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 swapper pgtable: 4k pages, 52-bit VAs, pgdp=0000000060f4d000 [fffff1ffc32d8008] pgd=100000006184b003, p4d=0000000000000000 Internal error: Oops: 0000000096000004 [#1] SMP CPU: 0 UID: 0 PID: 513 Comm: gcs_write_fault Tainted: G M 7.0.0-rc1 #1 PREEMPT Tainted: [M]=MACHINE_CHECK Hardware name: QEMU QEMU Virtual Machine, BIOS 2025.02-8+deb13u1 11/08/2025 pstate: 03402005 (nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) pc : zap_huge_pmd+0x168/0x468 lr : zap_huge_pmd+0x2c/0x468 sp : ffff800080beb660 x29: ffff800080beb660 x28: fff00000c2058180 x27: ffff800080beb898 x26: fff00000c2058180 x25: ffff800080beb820 x24: 00c800010b600f41 x23: ffffc1ffc30af1a8 x22: fff00000c2058180 x21: 0000ffff8dc00000 x20: fff00000c2bc6370 x19: ffff800080beb898 x18: ffff800080bebb60 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000007 x14: 000000000000000a x13: 0000aaaacbbbffff x12: 0000000000000000 x11: 0000ffff8ddfffff x10: 00000000000001fe x9 : 0000ffff8ddfffff x8 : 0000ffff8de00000 x7 : 0000ffff8da00000 x6 : fff00000c2bc6370 x5 : 0000ffff8da00000 x4 : 000000010b600000 x3 : ffffc1ffc0000000 x2 : fff00000c2058180 x1 : fffff1ffc32d8000 x0 : 000000c00010b600 Call trace: zap_huge_pmd+0x168/0x468 (P) unmap_page_range+0xd70/0x1560 unmap_single_vma+0x48/0x80 unmap_vmas+0x90/0x180 unmap_region+0x88/0xe4 vms_complete_munmap_vmas+0xf8/0x1e0 do_vmi_align_munmap+0x158/0x180 do_vmi_munmap+0xac/0x160 __vm_munmap+0xb0/0x138 vm_munmap+0x14/0x20 gcs_free+0x70/0x80 mm_release+0x1c/0xc8 exit_mm_release+0x28/0x38 do_exit+0x190/0x8ec do_group_exit+0x34/0x90 get_signal+0x794/0x858 arch_do_signal_or_restart+0x11c/0x3e0 exit_to_user_mode_loop+0x10c/0x17c el0_da+0x8c/0x9c el0t_64_sync_handler+0xd0/0xf0 el0t_64_sync+0x198/0x19c Code: aa1603e2 d34cfc00 cb813001 8b011861 (f9400420) Similarly to how the kernel handles protection_map[], use a gcs_page_prot variable to store the protection bits and clear PTE_SHARED if LPA2 is enabled. Also remove the unused PAGE_GCS{,_RO} macros. Signed-off-by: Catalin Marinas Fixes: 6497b66ba694 ("arm64/mm: Map pages for guarded control stack") Reported-by: Emanuele Rocca Cc: stable@vger.kernel.org Cc: Mark Brown Cc: Will Deacon Reviewed-by: David Hildenbrand (Arm) Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman

arm64: io: Rename ioremap_prot() to __ioremap_prot()

2026-03-12T11:09:20Z

[ Upstream commit f6bf47ab32e0863df50f5501d207dcdddb7fc507 ] Rename our ioremap_prot() implementation to __ioremap_prot() and convert all arch-internal callers over to the new function. ioremap_prot() remains as a #define to __ioremap_prot() for generic_access_phys() and will be subsequently extended to handle user permissions in 'prot'. Cc: Zeng Heng Cc: Jinjiang Tu Cc: Catalin Marinas Reviewed-by: Catalin Marinas Signed-off-by: Will Deacon Stable-dep-of: 8f098037139b ("arm64: io: Extract user memory type in ioremap_prot()") Signed-off-by: Sasha Levin

arm64: mte: Set TCMA1 whenever MTE is present in the kernel

2026-03-04T12:19:40Z

[ Upstream commit a4e5927115f30a301f9939ed43e6a21a343e06ad ] Set the TCMA1 bit so that access to TTBR1 addresses with 0xf in their tag bits will be treated as tag unchecked. This is important to avoid unwanted tag checking on some systems. Specifically, SCTLR_EL1.TCF can be set to indicate that no tag check faults are desired. But the architecture doesn't guarantee that in this case the system won't still perform tag checks. Use TCMA1 to ensure that undesired tag checks are not performed. This bit was already set in the KASAN case. Adding it to the non-KASAN case prevents tag checking since all TTBR1 address will have a value of 0xf in their tag bits. This patch has been measured on an Ampere system to improve the following: * Eliminate over 98% of kernel-side tag checks during "perf bench futex hash", as measured with "perf stat". * Eliminate all MTE overhead (was previously a 25% performance penalty) from the Phoronix pts/memcached benchmark (1:10 Set:Get ration with 96 cores). Reported-by: Taehyun Noh Suggested-by: Catalin Marinas Signed-off-by: Carl Worth Reviewed-by: Catalin Marinas Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64/gcs: Fix error handling in arch_set_shadow_stack_status()

2026-02-26T23:00:44Z

[ Upstream commit 53c998527ffa60f9deda8974a11ad39790684159 ] alloc_gcs() returns an error-encoded pointer on failure, which comes from do_mmap(), not NULL. The current NULL check fails to detect errors, which could lead to using an invalid GCS address. Use IS_ERR_VALUE() to properly detect errors, consistent with the check in gcs_alloc_thread_stack(). Fixes: b57180c75c7e ("arm64/gcs: Implement shadow stack prctl() interface") Reviewed-by: Mark Brown Signed-off-by: Breno Leitao Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64: Fix cleared E0POE bit after cpu_suspend()/resume()

2026-01-09T10:41:45Z

TCR2_ELx.E0POE is set during smp_init(). However, this bit is not reprogrammed when the CPU enters suspension and later resumes via cpu_resume(), as __cpu_setup() does not re-enable E0POE and there is no save/restore logic for the TCR2_ELx system register. As a result, the E0POE feature no longer works after cpu_resume(). To address this, save and restore TCR2_EL1 in the cpu_suspend()/cpu_resume() path, rather than adding related logic to __cpu_setup(), taking into account possible future extensions of the TCR2_ELx feature. Fixes: bf83dae90fbc ("arm64: enable the Permission Overlay Extension for EL0") Cc: # 6.12.x Signed-off-by: Yeoreum Yun Reviewed-by: Anshuman Khandual Reviewed-by: Kevin Brodsky Signed-off-by: Catalin Marinas

arm64: mm: Fix incomplete tag reset in change_memory_common()

2026-01-08T19:47:59Z

Running KASAN KUnit tests with {HW,SW}_TAGS mode triggers a fault in change_memory_common(): Call trace: change_memory_common+0x168/0x210 (P) set_memory_ro+0x20/0x48 vmalloc_helpers_tags+0xe8/0x338 kunit_try_run_case+0x74/0x188 kunit_generic_run_threadfn_adapter+0x30/0x70 kthread+0x11c/0x200 ret_from_fork+0x10/0x20 ---[ end trace 0000000000000000 ]--- # vmalloc_helpers_tags: try faulted not ok 67 vmalloc_helpers_tags Commit a06494adb7ef ("arm64: mm: use untagged address to calculate page index") fixed a KASAN warning in the BPF subsystem by adding kasan_reset_tag() to the index calculation. In the execmem flow: bpf_prog_pack_alloc() -> bpf_jit_alloc_exec() -> execmem_alloc() The returned address from execmem_vmalloc/execmem_cache_alloc is passed through kasan_reset_tag(), so start has no tag while area->addr still retains the original tag. The fix correctly handled this case by resetting the tag on area->addr: (start - (unsigned long)kasan_reset_tag(area->addr)) >> PAGE_SHIFT However, in normal vmalloc paths, both start and area->addr have matching tags(or no tags). Resetting only area->addr causes a mismatch when subtracting a tagged address from an untagged one, resulting in an incorrect index. Fix this by resetting tags on both addresses in the index calculation. This ensures correct results regardless of the tag state of either address. Tested with KASAN KUnit tests under CONFIG_KASAN_GENERIC, CONFIG_KASAN_SW_TAGS, and CONFIG_KASAN_HW_TAGS - all pass. Also verified the original BPF KASAN warning from [1] is still fixed. [1] https://lore.kernel.org/all/20251118164115.GA3977565@ax162/ Fixes: a06494adb7ef ("arm64: mm: use untagged address to calculate page index") Signed-off-by: Jiayuan Chen Signed-off-by: Jiayuan Chen Signed-off-by: Catalin Marinas

arm64: mm: Simplify check in arch_kfence_init_pool()

2025-12-15T12:01:08Z

TL;DR: checking force_pte_mapping() in arch_kfence_init_pool() is sufficient Commit ce2b3a50ad92 ("arm64: mm: Don't sleep in split_kernel_leaf_mapping() when in atomic context") recently added an arm64 implementation of arch_kfence_init_pool() to ensure that the KFENCE pool is PTE-mapped. Assuming that the pool was not initialised early, block splitting is necessary if the linear mapping is not fully PTE-mapped, in other words if force_pte_mapping() is false. arch_kfence_init_pool() currently makes another check: whether BBML2-noabort is supported, i.e. whether we are *able* to split block mappings. This check is however unnecessary, because force_pte_mapping() is always true if KFENCE is enabled and BBML2-noabort is not supported. This must be the case by design, since KFENCE requires PTE-mapped pages in all cases. We can therefore remove that check. The situation is different in split_kernel_leaf_mapping(), as that function is called unconditionally regardless of the configuration. If BBML2-noabort is not supported, it cannot do anything and bails out. If force_pte_mapping() is true, there is nothing to do and it also bails out, but these are independent checks. Commit 53357f14f924 ("arm64: mm: Tidy up force_pte_mapping()") grouped these checks into a helper, split_leaf_mapping_possible(). This isn't so helpful as only split_kernel_leaf_mapping() should check both. Revert the parts of that commit that introduced the helper, reintroducing the more accurate comments in split_kernel_leaf_mapping(). Signed-off-by: Kevin Brodsky Reviewed-by: Ryan Roberts Signed-off-by: Catalin Marinas

Merge tag 'mm-stable-2025-12-03-21-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-12-05T21:52:43Z

Pull MM updates from Andrew Morton: "__vmalloc()/kvmalloc() and no-block support" (Uladzislau Rezki) Rework the vmalloc() code to support non-blocking allocations (GFP_ATOIC, GFP_NOWAIT) "ksm: fix exec/fork inheritance" (xu xin) Fix a rare case where the KSM MMF_VM_MERGE_ANY prctl state is not inherited across fork/exec "mm/zswap: misc cleanup of code and documentations" (SeongJae Park) Some light maintenance work on the zswap code "mm/page_owner: add debugfs files 'show_handles' and 'show_stacks_handles'" (Mauricio Faria de Oliveira) Enhance the /sys/kernel/debug/page_owner debug feature by adding unique identifiers to differentiate the various stack traces so that userspace monitoring tools can better match stack traces over time "mm/page_alloc: pcp->batch cleanups" (Joshua Hahn) Minor alterations to the page allocator's per-cpu-pages feature "Improve UFFDIO_MOVE scalability by removing anon_vma lock" (Lokesh Gidra) Address a scalability issue in userfaultfd's UFFDIO_MOVE operation "kasan: cleanups for kasan_enabled() checks" (Sabyrzhan Tasbolatov) "drivers/base/node: fold node register and unregister functions" (Donet Tom) Clean up the NUMA node handling code a little "mm: some optimizations for prot numa" (Kefeng Wang) Cleanups and small optimizations to the NUMA allocation hinting code "mm/page_alloc: Batch callers of free_pcppages_bulk" (Joshua Hahn) Address long lock hold times at boot on large machines. These were causing (harmless) softlockup warnings "optimize the logic for handling dirty file folios during reclaim" (Baolin Wang) Remove some now-unnecessary work from page reclaim "mm/damon: allow DAMOS auto-tuned for per-memcg per-node memory usage" (SeongJae Park) Enhance the DAMOS auto-tuning feature "mm/damon: fixes for address alignment issues in DAMON_LRU_SORT and DAMON_RECLAIM" (Quanmin Yan) Fix DAMON_LRU_SORT and DAMON_RECLAIM with certain userspace configuration "expand mmap_prepare functionality, port more users" (Lorenzo Stoakes) Enhance the new(ish) file_operations.mmap_prepare() method and port additional callsites from the old ->mmap() over to ->mmap_prepare() "Fix stale IOTLB entries for kernel address space" (Lu Baolu) Fix a bug (and possible security issue on non-x86) in the IOMMU code. In some situations the IOMMU could be left hanging onto a stale kernel pagetable entry "mm/huge_memory: cleanup __split_unmapped_folio()" (Wei Yang) Clean up and optimize the folio splitting code "mm, swap: misc cleanup and bugfix" (Kairui Song) Some cleanups and a minor fix in the swap discard code "mm/damon: misc documentation fixups" (SeongJae Park) "mm/damon: support pin-point targets removal" (SeongJae Park) Permit userspace to remove a specific monitoring target in the middle of the current targets list "mm: MISC follow-up patches for linux/pgalloc.h" (Harry Yoo) A couple of cleanups related to mm header file inclusion "mm/swapfile.c: select swap devices of default priority round robin" (Baoquan He) improve the selection of swap devices for NUMA machines "mm: Convert memory block states (MEM_*) macros to enums" (Israel Batista) Change the memory block labels from macros to enums so they will appear in kernel debug info "ksm: perform a range-walk to jump over holes in break_ksm" (Pedro Demarchi Gomes) Address an inefficiency when KSM unmerges an address range "mm/damon/tests: fix memory bugs in kunit tests" (SeongJae Park) Fix leaks and unhandled malloc() failures in DAMON userspace unit tests "some cleanups for pageout()" (Baolin Wang) Clean up a couple of minor things in the page scanner's writeback-for-eviction code "mm/hugetlb: refactor sysfs/sysctl interfaces" (Hui Zhu) Move hugetlb's sysfs/sysctl handling code into a new file "introduce VM_MAYBE_GUARD and make it sticky" (Lorenzo Stoakes) Make the VMA guard regions available in /proc/pid/smaps and improves the mergeability of guarded VMAs "mm: perform guard region install/remove under VMA lock" (Lorenzo Stoakes) Reduce mmap lock contention for callers performing VMA guard region operations "vma_start_write_killable" (Matthew Wilcox) Start work on permitting applications to be killed when they are waiting on a read_lock on the VMA lock "mm/damon/tests: add more tests for online parameters commit" (SeongJae Park) Add additional userspace testing of DAMON's "commit" feature "mm/damon: misc cleanups" (SeongJae Park) "make VM_SOFTDIRTY a sticky VMA flag" (Lorenzo Stoakes) Address the possible loss of a VMA's VM_SOFTDIRTY flag when that VMA is merged with another "mm: support device-private THP" (Balbir Singh) Introduce support for Transparent Huge Page (THP) migration in zone device-private memory "Optimize folio split in memory failure" (Zi Yan) "mm/huge_memory: Define split_type and consolidate split support checks" (Wei Yang) Some more cleanups in the folio splitting code "mm: remove is_swap_[pte, pmd]() + non-swap entries, introduce leaf entries" (Lorenzo Stoakes) Clean up our handling of pagetable leaf entries by introducing the concept of 'software leaf entries', of type softleaf_t "reparent the THP split queue" (Muchun Song) Reparent the THP split queue to its parent memcg. This is in preparation for addressing the long-standing "dying memcg" problem, wherein dead memcg's linger for too long, consuming memory resources "unify PMD scan results and remove redundant cleanup" (Wei Yang) A little cleanup in the hugepage collapse code "zram: introduce writeback bio batching" (Sergey Senozhatsky) Improve zram writeback efficiency by introducing batched bio writeback support "memcg: cleanup the memcg stats interfaces" (Shakeel Butt) Clean up our handling of the interrupt safety of some memcg stats "make vmalloc gfp flags usage more apparent" (Vishal Moola) Clean up vmalloc's handling of incoming GFP flags "mm: Add soft-dirty and uffd-wp support for RISC-V" (Chunyan Zhang) Teach soft dirty and userfaultfd write protect tracking to use RISC-V's Svrsw60t59b extension "mm: swap: small fixes and comment cleanups" (Youngjun Park) Fix a small bug and clean up some of the swap code "initial work on making VMA flags a bitmap" (Lorenzo Stoakes) Start work on converting the vma struct's flags to a bitmap, so we stop running out of them, especially on 32-bit "mm/swapfile: fix and cleanup swap list iterations" (Youngjun Park) Address a possible bug in the swap discard code and clean things up a little [ This merge also reverts commit ebb9aeb980e5 ("vfio/nvgrace-gpu: register device memory for poison handling") because it looks broken to me, I've asked for clarification - Linus ] * tag 'mm-stable-2025-12-03-21-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits) mm: fix vma_start_write_killable() signal handling mm/swapfile: use plist_for_each_entry in __folio_throttle_swaprate mm/swapfile: fix list iteration when next node is removed during discard fs/proc/task_mmu.c: fix make_uffd_wp_huge_pte() huge pte handling mm/kfence: add reboot notifier to disable KFENCE on shutdown memcg: remove inc/dec_lruvec_kmem_state helpers selftests/mm/uffd: initialize char variable to Null mm: fix DEBUG_RODATA_TEST indentation in Kconfig mm: introduce VMA flags bitmap type tools/testing/vma: eliminate dependency on vma->__vm_flags mm: simplify and rename mm flags function for clarity mm: declare VMA flags by bit zram: fix a spelling mistake mm/page_alloc: optimize lowmem_reserve max lookup using its semantic monotonicity mm/vmscan: skip increasing kswapd_failures when reclaim was boosted pagemap: update BUDDY flag documentation mm: swap: remove scan_swap_map_slots() references from comments mm: swap: change swap_alloc_slow() to void mm, swap: remove redundant comment for read_swap_cache_async mm, swap: use SWP_SOLIDSTATE to determine if swap is rotational ...