kernel/linux.git/arch, branch v6.1.178

perf/x86/amd/core: Always use the NMI latency mitigation

2026-07-24T13:55:19+00:00

commit 73a4c02f94a98d94480c3e5c81450215a4da05ba upstream. Commit df4d29732fda ("perf/x86/amd: Change/fix NMI latency mitigation to use a timestamp") fixed handling of late-arriving NMIs but limited the mitigation to processors having X86_FEATURE_PERFCTR_CORE. However, it is unclear if processors without this feature are also affected. When Mediated vPMU is enabled on affected hardware, it is also possible to bypass the fix inside KVM guests if X86_FEATURE_PERFCTR_CORE is removed from the guest CPUID (e.g. using "-cpu host,-perfctr-core" with QEMU). Hence, use the mitigation at all times. Fixes: df4d29732fda ("perf/x86/amd: Change/fix NMI latency mitigation to use a timestamp") Signed-off-by: Sandipan Das Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/29a3c970da289ab8f24282933bdb36545c0403e8.1780325517.git.sandipan.das@amd.com Signed-off-by: Greg Kroah-Hartman

KVM: Move kvm_io_bus_get_dev() locking responsibilities to callers

2026-07-24T13:55:18+00:00

commit 3a07249981629ace483ebbef81ef6b34c2d2afec upstream. kvm_io_bus_get_dev() returns a device that is only matched by the address, and nothing else. This can cause a lifetime issue if the matched device is not the expected type, as by the time the caller can introspect the object, it might be gone (the srcu lock having been dropped). Given that there is only a single user of this helper, the simplest option is to move the locking responsibility to the caller, which can keep the srcu lock held for as long as it wants. Note that this aligns with other kvm_io_bus*() helpers, which already require the srcu lock to be held by the callers. Reported-by: Will Deacon Fixes: 8a39d00670f07 ("KVM: kvm_io_bus: Add kvm_io_bus_get_dev() call") Link: https://lore.kernel.org/all/20260626111344.802555-1-maz@kernel.org Cc: stable@vger.kernel.org Reviewed-by: Oliver Upton Link: https://patch.msgid.link/20260627105105.1005990-1-maz@kernel.org Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman

powerpc/spufs: fix out-of-bounds access in spufs_mem_mmap_access()

2026-07-24T13:55:10+00:00

commit 47b87f469a35b5ffc81c16eee6b13a9b6c8d55c6 upstream. spufs_mem_mmap_access() computes the local store offset as address - vma->vm_start, but bounds-checks it against vma->vm_end instead of the local store size. On 64-bit, offset is always well below vma->vm_end, so the clamp never fires and len stays unbounded against the LS_SIZE buffer returned by ctx->ops->get_ls(). Reject offsets at or beyond LS_SIZE and clamp len to the remaining space, mirroring the guard already used by spufs_mem_mmap_fault() and spufs_ps_fault(). Fixes: a352894d0705 ("spufs: use new vm_ops->access to allow local state access from gdb") Reported-by: Yuhao Jiang Cc: stable@vger.kernel.org Signed-off-by: Junrui Luo Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/SYBPR01MB7881EE775E8B51C09F5A29E7AF152@SYBPR01MB7881.ausprd01.prod.outlook.com Signed-off-by: Greg Kroah-Hartman

powerpc/pseries: fix memory leak on krealloc failure in papr_init

2026-07-24T13:55:10+00:00

commit bd83c98b988d2c560531084e296dbfb530aff829 upstream. When krealloc() fails, free the original esi_buf before returning to avoid a memory leak. Fixes: 3c14b73454cf ("powerpc/pseries: Interface to represent PAPR firmware attributes") Cc: stable@vger.kernel.org Signed-off-by: Thorsten Blum Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260614142356.658212-2-thorsten.blum@linux.dev Signed-off-by: Greg Kroah-Hartman

riscv: Prevent NULL pointer dereference in machine_kexec_prepare()

2026-07-24T13:55:10+00:00

commit 81bbcff0c053c4f5c711c31a9b72fc492bd96c3f upstream. A NULL pointer dereference issue is noticed in riscv's machine_kexec_prepare(), where image->segment[i].buf might be NULL and copied unchecked. The NULL buf comes from ima_add_kexec_buffer(), where kbuf is added by kexec_add_buffer(), but kbuf.buffer is NULL, then it is copied without a check in machine_kexec_prepare(): kexec_file_load -> kimage_file_alloc_init() -> kimage_file_prepare_segments() -> ima_add_kexec_buffer() -> kexec_add_buffer() -> machine_kexec_prepare() -> memcpy() Address this by adding a check before the data copy attempt. Fixes: b7fb4d78a6ad ("RISC-V: use memcpy for kexec_file mode") Cc: stable@vger.kernel.org Closes: https://lore.kernel.org/kexec/CAO7dBbVftLUhd2qrh7hmijTB3PEPfZAhykCGqEfrPoOcSrrj-w@mail.gmail.com/ Acked-by: Baoquan He Acked-by: Pratyush Yadav Reviewed-by: Nutty Liu Signed-off-by: Tao Liu Link: https://patch.msgid.link/20260705232706.30265-2-ltao@redhat.com Signed-off-by: Paul Walmsley Signed-off-by: Greg Kroah-Hartman

LoongArch: Fix missing dirty page tracking in {pte,pmd}_wrprotect()

2026-07-24T13:55:08+00:00

commit 018e9828eb523c638fa3d9bdf0fd4956b74555b2 upstream. When hardware page table walker (PTW) is enabled on LoongArch, the CPU may set _PAGE_DIRTY directly in the page table entry during a write TLB miss, without going through the software TLB store handler. The software TLB store handler (tlbex.S:254) sets both _PAGE_DIRTY and_PAGE_MODIFIED together: ori t0, t0, (_PAGE_VALID | _PAGE_DIRTY | _PAGE_MODIFIED) Since hardware PTW only sets _PAGE_DIRTY, the software-only bit, i.e. _PAGE_MODIFIED is left unchanged. This creates a window where a PTE has _PAGE_DIRTY set (hardware knows the page is dirty) but _PAGE_MODIFIED clear (software is unaware). When fork()/clone() triggers copy-on-write, __copy_present_ptes() calls pte_wrprotect(), which unconditionally clears both the _PAGE_WRITE and _PAGE_DIRTY bits: pte_val(pte) &= ~(_PAGE_WRITE | _PAGE_DIRTY); Since _PAGE_MODIFIED was never set, the dirtiness information is lost completely. Subsequently, when memory pressure triggers page reclaim, page_mkclean() / try_to_unmap() sees the page as clean (i.e. pte_dirty() returns false) and the page may be freed without writeback, causing data corruption. Fix this by propagating the _PAGE_DIRTY bit to the _PAGE_MODIFIED bit in both pte_wrprotect() and pmd_wrprotect() before clearing writeable bits: if (pte_val(pte) & _PAGE_DIRTY) pte_val(pte) |= _PAGE_MODIFIED; The pmd_wrprotect() fix handles the CONFIG_TRANSPARENT_HUGEPAGE case, where pmd entries need the same treatment. This ensures the software dirty tracking bit (checked by pte_dirty() and pmd_dirty(), which read both the _PAGE_DIRTY and _PAGE_MODIFIED bits) is preserved across fork COW write-protection. The issue was found by the LTP madvise09 test case, which exercises page reclaim after "madvise(MADV_FREE), write and fork" operation sequence on private anonymous mappings. Cc: stable@vger.kernel.org Fixes: 09cfefb7fa70 ("LoongArch: Add memory management") Co-developed-by: Tianyang Zhang Signed-off-by: Tianyang Zhang Signed-off-by: Hongchen Zhang Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

riscv: cacheinfo: Fix node reference leak in populate_cache_leaves

2026-07-24T13:55:02+00:00

commit bf4a195f063b0a0805c1417f6aad1dd32ea48f0f upstream. Currently, the while loop drops the reference to prev in each iteration. If the loop terminates early due to a break, the final of_node_put(np) correctly drops the reference to the current node. However, if the loop terminates naturally because np == NULL, calling of_node_put(np) is a no-op. This leaves the last valid node stored in prev without its reference dropped, resulting in a node reference leak. Fix this by changing the final `of_node_put(np)` to `of_node_put(prev)`. Fixes: 94f9bf118f1e ("RISC-V: Fix of_node_* refcount") Cc: stable@vger.kernel.org Assisted-by: Gemini:gemini-3.1-pro Signed-off-by: Zishun Yi Link: https://patch.msgid.link/20260509074040.1747800-1-vulab@iscas.ac.cn Signed-off-by: Paul Walmsley Signed-off-by: Greg Kroah-Hartman

mips: sched: Fix CPUMASK_OFFSTACK memory corruption

2026-07-24T13:55:02+00:00

commit 98e37db4a34d3af3fb2f4648295c25b5e40b20e3 upstream. This patch addresses a critical memory management flaw. When CONFIG_CPUMASK_OFFSTACK is enabled, cpumask_var_t is a pointer. Consequently, sizeof(new_mask) evaluates to the pointer size, causing copy_from_user() to clobber the mask pointer. Furthermore, the old logic performed copy_from_user() before allocating the mask. Fix this by allocating new_mask first. To handle variable-sized user masks correctly, use cpumask_size() to truncate overly large user masks or pad undersized masks with zeros before copying the data directly into the allocated buffer. Fixes: 295cbf6d63165 ("[MIPS] Move FPU affinity code into separate file.") Cc: stable@vger.kernel.org Signed-off-by: Aaron Tomlin Signed-off-by: Thomas Bogendoerfer Signed-off-by: Greg Kroah-Hartman

MIPS: DEC: Ensure 32-bit stack location for o32 prom_printf()

2026-07-24T13:55:01+00:00

commit 5ff79e8bdc75db51e30298a75939e2308e7658e0 upstream. In 64-bit configurations calling any firmware entry points from a kernel thread other than the initial one will result in a situation where the stack has been placed in the XKPHYS 64-bit memory segment. Consequently the stack pointer is no longer a 32-bit value and when the 32-bit firmware code called uses 32-bit ALU operations to manipulate the stack pointer, the calculated result is incorrect (in fact in the 64-bit MIPS ISA almost all 32-bit ALU operations will produce an unpredictable result when executed on 64-bit data) and control goes astray. This may happen when no final console driver has been enabled in the configuration and consequently the initial console continues being used late into bootstrap, or with an upcoming change that will switch the zs driver to use a platform device, which in turn will make the console handover happen only after other kernel threads have already been started, and the kernel will hang at: pid_max: default: 32768 minimum: 301 or somewhat later, but always before: cblist_init_generic: Setting adjustable number of callback queues. has been printed. It seems that only the prom_printf() entry point is affected. Of all the other entry points wired only rex_slot_address() and rex_gettcinfo() are called from a kernel thread other than the initial one, specifically kernel_init(), and they are leaf functions that do no business with the stack, having worked with no issue ever since 64-bit support was added for the platform back in 2002. To address this issue then, arrange for the stack to be switched in the o32 wrapper as required for prom_printf() only, by supplying call_o32() with a pointer to a chunk of initdata space, which is placed in the CKSEG0 32-bit compatibility segment, observing that prom_printf() is only called from console output handler and therefore with the console lock held, implying no need for this code to be reentrant. Other firmware entry points may be called with interrupts enabled and no lock held, and may therefore require that call_o32() be reentrant. They trigger no issue at this point and "if it ain't broke, don't fix it," so just leave them alone. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Maciej W. Rozycki Cc: stable@vger.kernel.org # v2.6.12+ Signed-off-by: Thomas Bogendoerfer Signed-off-by: Greg Kroah-Hartman

MIPS: ip22-gio: fix device reference leak in probe

2026-07-24T13:55:01+00:00

commit b82930a4c5dbc5c4df39c0f93d968c239f2c6885 upstream. The gio probe function needlessly takes a device reference which is never released and therefore prevents unbound gio devices from being freed. Fixes: e84de0c61905 ("MIPS: GIO bus support for SGI IP22/28") Cc: stable@vger.kernel.org # 3.3 Cc: Thomas Bogendoerfer Signed-off-by: Johan Hovold Signed-off-by: Thomas Bogendoerfer Signed-off-by: Greg Kroah-Hartman