kernel/linux.git/arch/riscv, branch v7.1.12

riscv: lib: Fix ZBB strnlen reading past count boundary

2026-08-23T12:29:30+00:00

[ Upstream commit 5d588c684833e678a0008eb69c33190f01a65f4b ] The ZBB-optimized strnlen loop loads one word ahead before checking the aligned boundary: REG_L t1, SZREG(t0) // load next word addi t0, t0, SZREG // advance orc.b t1, t1 bgeu t0, t4, 4f // boundary check AFTER load where t4 = (s + count) & -SZREG. When s is aligned and count is a multiple of SZREG, t4 equals s + count and the loop loads a full word starting at exactly s + count. If s + count falls on a page boundary with the next page unmapped, this faults. Fix by computing the aligned boundary from the last valid byte (s + count - 1) instead of s + count. This makes the loop stop at the word containing the last valid byte rather than potentially loading the word after it. The count == 0 case is already handled by the beqz early exit. Also add a pre-loop guard (bgeu t0, t4) for the case where all valid bytes fit within the first word. With the adjusted boundary, t4 can equal t0, and entering the loop with stale register state from the first-word processing would produce incorrect results. The final minu clamp ensures the result is still correct when the last loaded word extends past s + count - 1 within the same aligned word. Fixes: 5ba15d419fab ("riscv: lib: add strnlen() implementation") Signed-off-by: Michael Neuling Assisted-by: Claude Opus4.6 High Thinking Link: https://patch.msgid.link/20260413010738.1622423-1-mikey@neuling.org Signed-off-by: Paul Walmsley Signed-off-by: Sasha Levin

riscv: ftrace: Fix ftrace_modify_call failure on kprobed functions

2026-08-23T12:29:30+00:00

[ Upstream commit 2820d227ad4ee70805d693d698437cc3e88d6c3d ] We are frequently hitting the following splat during the riscv bpf selftests: 00000000026dc75a: expected (7c3ff297) but got (00100073) ------------[ ftrace bug ]------------ ftrace failed to modify [] bpf_kfunc_common_test+0x4/0x20 [bpf_testmod] actual: e7:82:c2:ce Updating ftrace call site to call a different ftrace function ftrace record flags: 80100002 (2) expected tramp: ffffffff80043904 ------------[ cut here ]------------ WARNING: kernel/trace/ftrace.c:2278 at ftrace_bug+0x46e/0x4b0, CPU#1: test_progs/98 ... [] ftrace_bug+0x46e/0x4b0 [] ftrace_replace_code+0x16e/0x170 [] ftrace_modify_all_code+0x12e/0x1b8 [] arch_ftrace_update_code+0x14/0x28 [] ftrace_startup+0x14c/0x2a0 [] ftrace_startup_subops+0x584/0x1050 [] register_ftrace_graph+0x4e6/0x1018 [] register_fprobe_ips+0xc66/0x12f8 [] bpf_kprobe_multi_link_attach+0x5d8/0xe68 [] __sys_bpf+0x3d5a/0x47f0 [] __riscv_sys_bpf+0xae/0x168 [] syscall_handler+0x60/0x100 [] do_trap_ecall_u+0x174/0x208 [] handle_exception+0x16c/0x178 After debugging, it can be triggered by similar commands below: ``` echo do_nanosleep > set_ftrace_filter echo function > current_tracer echo 'p do_nanosleep' > kprobe_events echo 1 > events/kprobes/enable echo 'f do_nanosleep' > dynamic_events echo 1 > events/fprobes/enable ``` The reason is that attaching a kprobe to an ftrace-traced function entry replaces its initial auipc insn with ebreak. When ftrace_modify_call later runs, it expects auipc insn, so verification fails and triggers ftrace_bug. The expected auipc logic remains conceptually unchanged, and kprobe single-stepping ensures normal execution. Therefore, if the first insn is ebreak, bypassing the check to continue patching the jalr insn is safe and avoids ftrace failures. Fixes: b2137c3b6d7a ("riscv: ftrace: prepare ftrace for atomic code patching") Signed-off-by: Pu Lehui Link: https://patch.msgid.link/20260802094929.3978390-1-pulehui@huaweicloud.com [pjw@kernel.org: fixed reproducer in commit message] Signed-off-by: Paul Walmsley Signed-off-by: Sasha Levin

riscv: hwprobe: Register unaligned probes before usermode

2026-08-23T12:29:23+00:00

commit 994dad686e755477e2b2700cca4e6e1a90a58bdc upstream. The hwprobe vDSO data is populated by the first riscv_hwprobe syscall. Some values, such as MISALIGNED_VECTOR_PERF, may depend on the async vector unaligned access speed probe registered by check_unaligned_access_all_cpus(). That initcall currently runs at late_initcall level. However, rootfs_initcall enables usermode helpers before late initcalls run, so an early helper can execute userspace and call riscv_hwprobe first. In that case complete_hwprobe_vdso_data() consumes the initial pending_boot_probes reference, populates the vDSO cache, and marks it ready before the later async probe is registered. The eventual probe result then cannot update the already-ready cache. Move check_unaligned_access_all_cpus() to fs_initcall_sync. This still runs after clocksource_done_booting(), so the ktime_get_mono_fast_ns() benchmark uses a stable clocksource, but it runs before rootfs_initcall enables usermode helpers. Any async hwprobe probe is therefore registered before userspace can trigger the one-time vDSO cache population. Cc: stable@vger.kernel.org Fixes: 6455c6c11827 ("riscv: Clean up & optimize unaligned scalar access probe") Signed-off-by: Rui Qi Reviewed-by: Nam Cao Link: https://patch.msgid.link/20260721150511.1607105-1-qirui.001@bytedance.com Signed-off-by: Paul Walmsley Signed-off-by: Greg Kroah-Hartman

riscv/mm: use physical alignment for vmemmap_start_pfn

2026-08-09T18:26:47+00:00

commit 45ebe4540817cb540a59e4dc04014ac5dddc9990 upstream. RISC-V computes vmemmap_start_pfn by rounding phys_ram_base down to VMEMMAP_ADDR_ALIGN. That alignment must therefore be expressed in the physical-address domain. Commit 476849b0fba4 ("riscv/mm: align vmemmap to maximal folio size") attempted to account for the maximal folio alignment by feeding MAX_FOLIO_VMEMMAP_ALIGN directly into VMEMMAP_ADDR_ALIGN. However, MAX_FOLIO_VMEMMAP_ALIGN is measured in bytes of struct page storage, whereas VMEMMAP_ADDR_ALIGN is used to align a physical address. The mask-based compound_info encoding requires pfn_to_page(0) to be naturally aligned to MAX_FOLIO_VMEMMAP_ALIGN. Commit 9f94db4c7eaa ("mm/sparse: check memmap alignment for compound_info_has_mask()") added a check for that requirement and exposed the unit mismatch on systems such as QEMU virt, where the DRAM base is not aligned to MAX_FOLIO_NR_PAGES * PAGE_SIZE. Here is the log: [ 0.000000][ C0] ------------[ cut here ]------------ [ 0.000000][ C0] WARNING: mm/sparse.c:365 at sparse_init+0x58a/0x6fe, CPU#0: swapper/0 [ 0.000000][ C0] Modules linked in: [ 0.000000][ C0] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.2.0-rc3-g1d8304bdd65f #2 PREEMPT [ 0.000000][ C0] Hardware name: riscv-virtio,qemu (DT) [ 0.000000][ C0] epc : sparse_init+0x58a/0x6fe [ 0.000000][ C0] ra : sparse_init+0x58a/0x6fe [ 0.000000][ C0] epc : ffffffff86851c88 ra : ffffffff86851c88 sp : ffffffff88807a30 [ 0.000000][ C0] gp : ffffffff8a3bf240 tp : ffffffff88842080 t0 : ff600000ffab6000 [ 0.000000][ C0] t1 : 000000017fab6000 t2 : 65203a6573726363 s0 : ffffffff88807bc0 [ 0.000000][ C0] s1 : 000000000e000000 a0 : 0000000000000007 a1 : 0000000000000000 [ 0.000000][ C0] a2 : 0000000000000002 a3 : ffffffff86851c88 a4 : 0000000000000000 [ 0.000000][ C0] a5 : ffffffff88843080 a6 : 0000000000000003 a7 : 0000000000000000 [ 0.000000][ C0] s2 : ff60000000000000 s3 : 0040000000000000 s4 : 0004000000000000 [ 0.000000][ C0] s5 : ffffffff8a4d92e0 s6 : ff600000ffab55e0 s7 : ffffffff88384d00 [ 0.000000][ C0] s8 : 0000000000000003 s9 : ffffffff88384cc1 s10: ffffffff88384cc0 [ 0.000000][ C0] s11: ffffffff8a4daae0 t3 : ffffffff915e8b20 t4 : ffffffff915e8b20 [ 0.000000][ C0] t5 : ffffffff915e8b20 t6 : ffffffff915e8bc8 ssp : 0000000000000000 [ 0.000000][ C0] status: 0000000200000100 badaddr: ffffffff86851c88 cause: 0000000000000003 [ 0.000000][ C0] [] sparse_init+0x58a/0x6fe [ 0.000000][ C0] [] mm_core_init_early+0x116/0x1e30 [ 0.000000][ C0] [] start_kernel+0xd2/0x848 Convert MAX_FOLIO_VMEMMAP_ALIGN to the equivalent physical alignment before using it in VMEMMAP_ADDR_ALIGN. This keeps the existing round_down() logic while making the resulting vmemmap base satisfy the mask-alignment requirement. Link: https://lore.kernel.org/20260716115326.3466926-1-xujiakai2025@iscas.ac.cn Fixes: 476849b0fba4 ("riscv/mm: align vmemmap to maximal folio size") Signed-off-by: Jiakai Xu Reviewed-by: Kiryl Shutsemau (Meta) Cc: Albert Ou Cc: Alexandre Ghiti Cc: David Hildenbrand Cc: Guo Ren Cc: Mike Rapoport Cc: Muchun Song Cc: Nam Cao Cc: Palmer Dabbelt Cc: Vishal Moola (Oracle) Assisted-by: YuanSheng:DeepSeek-V4-Flash Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

riscv: vdso: Only try to install vDSO when present

2026-08-09T18:26:36+00:00

[ Upstream commit c052927905710de1ab7364bf1925efbd12517ea3 ] vdso.so.dbg is only built with CONFIG_MMU. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202607090258.iSAUYlO1-lkp@intel.com/ Fixes: f157d411a9eb ("riscv: add missing vdso_install target") Fixes: 3edf39916977 ("vDSO, kbuild: Provide vDSO debug variants at runtime") Signed-off-by: Thomas Weißschuh Link: https://patch.msgid.link/20260709-riscv-install-vdso-v1-1-0ba4345419ca@linutronix.de Signed-off-by: Paul Walmsley Signed-off-by: Sasha Levin

riscv: mm: Fix out-of-bounds page-table walk during memory hot-remove

2026-08-09T18:26:36+00:00

[ Upstream commit a0188cc133696627857d16054e43f9ebc7efc821 ] remove_pud_mapping() and remove_p4d_mapping() obtain a child table base with pud_offset(p4dp, 0) and p4d_offset(pgd, 0), then add the index for addr. RISC-V folds page-table levels at runtime. When a level is folded, its offset helper returns the parent entry itself, but the index can still be nonzero. Adding it walks past the parent table. Sv48 folds P4D, while Sv39 folds both P4D and PUD, so memory hot-remove can descend into unrelated memory and pass an invalid page to __free_pages(). This can trigger: kernel BUG at include/linux/mm.h:1810! VM_BUG_ON_PAGE(page_ref_count(page) == 0) arch_remove_memory+0x1e/0x5c try_remove_memory+0x15e/0x200 remove_memory+0x24/0x3c Only add the index when the corresponding page-table level is enabled, matching p4d_offset() and pud_offset(). Fixes: c75a74f4ba19 ("riscv: mm: Add memory hotplugging support") Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter Link: https://patch.msgid.link/20260729012132.24882-1-kmehltretter@gmail.com Signed-off-by: Paul Walmsley Signed-off-by: Sasha Levin

riscv: drop __init from vec_check_unaligned_access_speed_all_cpus

2026-08-09T18:26:36+00:00

[ Upstream commit f51fed61eea0daba2f95f1a6074085e4cd513c7b ] This function runs within a kthread and need not necessarily finish before system finishes boot and free_initmem() unmaps the .init.text section. This function makes calls to SBI for probing unaligned access speed, and if this is slow for some reason (say some debug prints were added to SBI), the kthread can still be running at this point and result in an instruction page fault when trying to fetch from the freed region. [ 25.642087] Unable to handle kernel paging request at virtual address ffffffff80a04ef8 [ 25.646694] Current vec_check_unali pgtable: 4K pagesize, 48-bit VAs, pgdp=0x00004000316e9000 [ 25.653170] [ffffffff80a04ef8] pgd=000010004be7e401, p4d=000010004be7e401, pud=000010004be7e001, pmd=000010000c3000e3 [ 25.661244] Oops [#1] [ 25.662997] Modules linked in: [ 25.665357] CPU: 3 UID: 0 PID: 42 Comm: vec_check_unali Not tainted 7.0.0-tt-blackhole-asrinivasan-00007-g30ff73f18211 #570 PREEMPTLAZY [ 25.674669] Hardware name: Tenstorrent Blackhole (DT) [ 25.678545] epc : vec_check_unaligned_access_speed_all_cpus+0x18/0x2c [ 25.683458] ra : vec_check_unaligned_access_speed_all_cpus+0x18/0x2c [ 25.688372] epc : ffffffff80a04ef8 ra : ffffffff80a04ef8 sp : ffff8f8000203e20 [ 25.693874] gp : ffffffff814dc168 tp : ffffaf8001ad9900 t0 : 0000000000000000 [ 25.699401] t1 : fffffffffffffff0 t2 : ffffaf8001ad9a10 s0 : ffff8f8000203e30 [ 25.704912] s1 : ffffaf80018dc780 a0 : 0000000000000000 a1 : 0000000000000002 [ 25.710407] a2 : 00000000000001f0 a3 : 0000000000000018 a4 : 0000000000000000 [ 25.715917] a5 : 0000000000000000 a6 : ffffaf8001c03d98 a7 : ffffaf8001c03e30 [ 25.721419] s2 : ffff8f8000023c98 s3 : ffffaf8001aa1240 s4 : ffffffff80a04ee0 [ 25.726937] s5 : 0000000000000000 s6 : 0000000000000000 s7 : 0000000000000000 [ 25.732450] s8 : 0000000000000000 s9 : 0000000000000000 s10: 0000000000000000 [ 25.737944] s11: 0000000000000000 t3 : 0000000000000002 t4 : 0000000000000402 [ 25.743481] t5 : 0000000000000040 t6 : 0000000000000004 ssp : 0000000000000000 [ 25.749024] status: 0000000200000120 badaddr: ffffffff80a04ef8 cause: 000000000000000c [ 25.755060] [] vec_check_unaligned_access_speed_all_cpus+0x18/0x2c [ 25.760964] [] kthread+0xd8/0xfc [ 25.764660] [] ret_from_fork_kernel+0x18/0x1c4 [ 25.769220] [] ret_from_fork_kernel_asm+0x16/0x18 [ 25.774018] Code: cccc cccc cccc cccc cccc cccc cccc cccc cccc cccc (cccc) cccc Drop __init from its signature so that this doesn't happen. Fixes: a00e022be531 ("riscv: Annotate unaligned access init functions") Signed-off-by: Anirudh Srinivasan Assisted-by: Claude:claude-opus-4-6 Link: https://patch.msgid.link/20260612-vec_unaligned_drop_init-v1-1-df969210ae34@oss.tenstorrent.com Signed-off-by: Paul Walmsley Signed-off-by: Sasha Levin

mm/sparse-vmemmap: pass @pgmap argument to memory deactivation paths

2026-08-03T09:26:03+00:00

[ Upstream commit 3bbc54dd1b62f1a4b218c70aafbeceeba7c90c5d ] Currently, the memory hot-remove call chain -- arch_remove_memory(), __remove_pages(), sparse_remove_section() and section_deactivate() -- does not carry the struct dev_pagemap pointer. This prevents the lower levels from knowing whether the section was originally populated with vmemmap optimizations (e.g., DAX with vmemmap optimization enabled). Without this information, we cannot call vmemmap_can_optimize() to determine if the vmemmap pages were optimized. As a result, the vmemmap page accounting during teardown will mistakenly assume a non-optimized allocation, leading to incorrect memmap statistics. To lay the groundwork for fixing the vmemmap page accounting, we need to pass the @pgmap pointer down to the deactivation location. Plumb the @pgmap argument through the APIs of arch_remove_memory(), __remove_pages() and sparse_remove_section(), mirroring the corresponding *_activate() paths. Link: https://lore.kernel.org/20260428081855.1249045-4-songmuchun@bytedance.com Signed-off-by: Muchun Song Acked-by: Mike Rapoport (Microsoft) Reviewed-by: Oscar Salvador Acked-by: David Hildenbrand (Arm) Acked-by: Liam R. Howlett Cc: "Aneesh Kumar K.V" Cc: Joao Martins Cc: Lorenzo Stoakes Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Nicholas Piggin Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton Stable-dep-of: 721a73e30c9e ("mm/sparse-vmemmap: fix DAX vmemmap accounting with optimization") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

RISC-V: KVM: Serialize virtual interrupt pending state updates

2026-08-03T09:25:25+00:00

commit d024a0a7879e6f37c0152aacf6d8e37b214a1738 upstream. KVM RISC-V tracks guest local interrupt state with two bitmaps: - irqs_pending: interrupts that should be visible to the guest - irqs_pending_mask: interrupts whose pending state changed The current code updates those bitmaps with independent atomic bitops and assumes a multiple-producer, single-consumer protocol. That model does not actually hold. kvm_riscv_vcpu_sync_interrupts() is not a pure consumer. When the guest changes guest-visible HVIP state, sync_interrupts() writes both irqs_pending and irqs_pending_mask to reflect the new guest state back into KVM state. As a result, irqs_pending and irqs_pending_mask form a single logical state transition, but they are not updated atomically as a pair. This allows a race where a newly injected interrupt is lost. For example: CPU0 CPU1 ---- ---- kvm_riscv_vcpu_set_interrupt(VS_SOFT) set_bit(VS_SOFT, irqs_pending) kvm_riscv_vcpu_sync_interrupts() sees guest-cleared HVIP.VSSIP sets irqs_pending_mask clear_bit(IRQ_VS_SOFT, irqs_pending) set_bit(VS_SOFT, irqs_pending_mask) kvm_vcpu_kick() After that interleaving, a later flush can update HVIP without VSSIP even though a new virtual interrupt was injected. In practice, the guest can remain blocked in WFI with work pending. The same pending/mask protocol is shared by VS soft interrupts, PMU overflow delivery, and AIA high interrupt synchronization, so the race is not limited to one interrupt source. Fix this by serializing all updates to irqs_pending and irqs_pending_mask with a per-vCPU raw spinlock. This keeps the pending bit and the dirty mask as one state transition across: - set/unset interrupt - guest HVIP sync - interrupt flush to guest CSR state - vCPU reset - AIA CSR writes that clear dirty state Use non-atomic bitmap operations while holding the lock. Hold the lock across the AIA sync, flush, and pending checks as well, so both bitmap words share the same serialization domain. This intentionally replaces the existing lockless protocol instead of trying to repair it with additional barriers. The problem is not memory ordering on a single field; it is that two separate bitmaps encode one shared state machine while both producers and sync paths can modify them. A per-vCPU raw spinlock keeps the fix small, local, and suitable for backporting. Fixes: cce69aff689e ("RISC-V: KVM: Implement VCPU interrupts and requests handling") Cc: stable@vger.kernel.org [ Adapted for 7.1.y: place the new 'unsigned long flags;' declaration in kvm_riscv_vcpu_general_set_csr() explicitly. A direct apply anchors it in kvm_riscv_vcpu_general_get_csr(), whose prologue is byte-identical, leaving 'flags' undeclared at its use site. ] Signed-off-by: Xie Bo Reviewed-by: Anup Patel Signed-off-by: Anup Patel Signed-off-by: Sasha Levin

riscv: hwprobe: Avoid uninitialized read in hwprobe_get_cpus()

2026-08-03T09:25:22+00:00

[ Upstream commit 5caae1deee89a6582c761d5dcd4b924b744426cc ] When cpusetsize < cpumask_size(), hwprobe_get_cpus() did not fully initialize its copy of the cpu mask, which could cause non-deterministic results from the riscv_hwprobe syscall on a system with more than 8 CPUs when the supplied cpu mask is empty. Address this by fully initializing the cpu mask. Fixes: e178bf146e4b ("RISC-V: hwprobe: Introduce which-cpus flag") Signed-off-by: Mark Harris Reviewed-by: Nam Cao Reviewed-by: Michael Ellerman Link: https://patch.msgid.link/20260714003056.73707-1-mark.hsj@gmail.com Signed-off-by: Paul Walmsley Signed-off-by: Sasha Levin