linux/kernel/bpf/syscall.c, branch v6.16

Merge tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-05-31T22:44:16Z

Pull MM updates from Andrew Morton: - "Add folio_mk_pte()" from Matthew Wilcox simplifies the act of creating a pte which addresses the first page in a folio and reduces the amount of plumbing which architecture must implement to provide this. - "Misc folio patches for 6.16" from Matthew Wilcox is a shower of largely unrelated folio infrastructure changes which clean things up and better prepare us for future work. - "memory,x86,acpi: hotplug memory alignment advisement" from Gregory Price adds early-init code to prevent x86 from leaving physical memory unused when physical address regions are not aligned to memory block size. - "mm/compaction: allow more aggressive proactive compaction" from Michal Clapinski provides some tuning of the (sadly, hard-coded (more sadly, not auto-tuned)) thresholds for our invokation of proactive compaction. In a simple test case, the reduction of a guest VM's memory consumption was dramatic. - "Minor cleanups and improvements to swap freeing code" from Kemeng Shi provides some code cleaups and a small efficiency improvement to this part of our swap handling code. - "ptrace: introduce PTRACE_SET_SYSCALL_INFO API" from Dmitry Levin adds the ability for a ptracer to modify syscalls arguments. At this time we can alter only "system call information that are used by strace system call tampering, namely, syscall number, syscall arguments, and syscall return value. This series should have been incorporated into mm.git's "non-MM" branch, but I goofed. - "fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions" from Andrei Vagin extends the info returned by the PAGEMAP_SCAN ioctl against /proc/pid/pagemap. This permits CRIU to more efficiently get at the info about guard regions. - "Fix parameter passed to page_mapcount_is_type()" from Gavin Shan implements that fix. No runtime effect is expected because validate_page_before_insert() happens to fix up this error. - "kernel/events/uprobes: uprobe_write_opcode() rewrite" from David Hildenbrand basically brings uprobe text poking into the current decade. Remove a bunch of hand-rolled implementation in favor of using more current facilities. - "mm/ptdump: Drop assumption that pxd_val() is u64" from Anshuman Khandual provides enhancements and generalizations to the pte dumping code. This might be needed when 128-bit Page Table Descriptors are enabled for ARM. - "Always call constructor for kernel page tables" from Kevin Brodsky ensures that the ctor/dtor is always called for kernel pgtables, as it already is for user pgtables. This permits the addition of more functionality such as "insert hooks to protect page tables". This change does result in various architectures performing unnecesary work, but this is fixed up where it is anticipated to occur. - "Rust support for mm_struct, vm_area_struct, and mmap" from Alice Ryhl adds plumbing to permit Rust access to core MM structures. - "fix incorrectly disallowed anonymous VMA merges" from Lorenzo Stoakes takes advantage of some VMA merging opportunities which we've been missing for 15 years. - "mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE" from SeongJae Park optimizes process_madvise()'s TLB flushing. Instead of flushing each address range in the provided iovec, we batch the flushing across all the iovec entries. The syscall's cost was approximately halved with a microbenchmark which was designed to load this particular operation. - "Track node vacancy to reduce worst case allocation counts" from Sidhartha Kumar makes the maple tree smarter about its node preallocation. stress-ng mmap performance increased by single-digit percentages and the amount of unnecessarily preallocated memory was dramaticelly reduced. - "mm/gup: Minor fix, cleanup and improvements" from Baoquan He removes a few unnecessary things which Baoquan noted when reading the code. - ""Enhance sysfs handling for memory hotplug in weighted interleave" from Rakie Kim "enhances the weighted interleave policy in the memory management subsystem by improving sysfs handling, fixing memory leaks, and introducing dynamic sysfs updates for memory hotplug support". Fixes things on error paths which we are unlikely to hit. - "mm/damon: auto-tune DAMOS for NUMA setups including tiered memory" from SeongJae Park introduces new DAMOS quota goal metrics which eliminate the manual tuning which is required when utilizing DAMON for memory tiering. - "mm/vmalloc.c: code cleanup and improvements" from Baoquan He provides cleanups and small efficiency improvements which Baoquan found via code inspection. - "vmscan: enforce mems_effective during demotion" from Gregory Price changes reclaim to respect cpuset.mems_effective during demotion when possible. because presently, reclaim explicitly ignores cpuset.mems_effective when demoting, which may cause the cpuset settings to violated. This is useful for isolating workloads on a multi-tenant system from certain classes of memory more consistently. - "Clean up split_huge_pmd_locked() and remove unnecessary folio pointers" from Gavin Guo provides minor cleanups and efficiency gains in in the huge page splitting and migrating code. - "Use kmem_cache for memcg alloc" from Huan Yang creates a slab cache for `struct mem_cgroup', yielding improved memory utilization. - "add max arg to swappiness in memory.reclaim and lru_gen" from Zhongkun He adds a new "max" argument to the "swappiness=" argument for memory.reclaim MGLRU's lru_gen. This directs proactive reclaim to reclaim from only anon folios rather than file-backed folios. - "kexec: introduce Kexec HandOver (KHO)" from Mike Rapoport is the first step on the path to permitting the kernel to maintain existing VMs while replacing the host kernel via file-based kexec. At this time only memblock's reserve_mem is preserved. - "mm: Introduce for_each_valid_pfn()" from David Woodhouse provides and uses a smarter way of looping over a pfn range. By skipping ranges of invalid pfns. - "sched/numa: Skip VMA scanning on memory pinned to one NUMA node via cpuset.mems" from Libo Chen removes a lot of pointless VMA scanning when a task is pinned a single NUMA mode. Dramatic performance benefits were seen in some real world cases. - "JFS: Implement migrate_folio for jfs_metapage_aops" from Shivank Garg addresses a warning which occurs during memory compaction when using JFS. - "move all VMA allocation, freeing and duplication logic to mm" from Lorenzo Stoakes moves some VMA code from kernel/fork.c into the more appropriate mm/vma.c. - "mm, swap: clean up swap cache mapping helper" from Kairui Song provides code consolidation and cleanups related to the folio_index() function. - "mm/gup: Cleanup memfd_pin_folios()" from Vishal Moola does that. - "memcg: Fix test_memcg_min/low test failures" from Waiman Long addresses some bogus failures which are being reported by the test_memcontrol selftest. - "eliminate mmap() retry merge, add .mmap_prepare hook" from Lorenzo Stoakes commences the deprecation of file_operations.mmap() in favor of the new file_operations.mmap_prepare(). The latter is more restrictive and prevents drivers from messing with things in ways which, amongst other problems, may defeat VMA merging. - "memcg: decouple memcg and objcg stocks"" from Shakeel Butt decouples the per-cpu memcg charge cache from the objcg's one. This is a step along the way to making memcg and objcg charging NMI-safe, which is a BPF requirement. - "mm/damon: minor fixups and improvements for code, tests, and documents" from SeongJae Park is yet another batch of miscellaneous DAMON changes. Fix and improve minor problems in code, tests and documents. - "memcg: make memcg stats irq safe" from Shakeel Butt converts memcg stats to be irq safe. Another step along the way to making memcg charging and stats updates NMI-safe, a BPF requirement. - "Let unmap_hugepage_range() and several related functions take folio instead of page" from Fan Ni provides folio conversions in the hugetlb code. * tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (285 commits) mm: pcp: increase pcp->free_count threshold to trigger free_high mm/hugetlb: convert use of struct page to folio in __unmap_hugepage_range() mm/hugetlb: refactor __unmap_hugepage_range() to take folio instead of page mm/hugetlb: refactor unmap_hugepage_range() to take folio instead of page mm/hugetlb: pass folio instead of page to unmap_ref_private() memcg: objcg stock trylock without irq disabling memcg: no stock lock for cpu hot-unplug memcg: make __mod_memcg_lruvec_state re-entrant safe against irqs memcg: make count_memcg_events re-entrant safe against irqs memcg: make mod_memcg_state re-entrant safe against irqs memcg: move preempt disable to callers of memcg_rstat_updated memcg: memcg_rstat_updated re-entrant safe against irqs mm: khugepaged: decouple SHMEM and file folios' collapse selftests/eventfd: correct test name and improve messages alloc_tag: check mem_profiling_support in alloc_tag_init Docs/damon: update titles and brief introductions to explain DAMOS selftests/damon/_damon_sysfs: read tried regions directories in order mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject() mm/damon/paddr: remove unused variable, folio_list, in damon_pa_stat() mm/damon/sysfs-schemes: fix wrong comment on damons_sysfs_quota_goal_metric_strs ...

mm: rename try_alloc_pages() to alloc_pages_nolock()

2025-05-22T21:55:37Z

The "try_" prefix is confusing, since it made people believe that try_alloc_pages() is analogous to spin_trylock() and NULL return means EAGAIN. This is not the case. If it returns NULL there is no reason to call it again. It will most likely return NULL again. Hence rename it to alloc_pages_nolock() to make it symmetrical to free_pages_nolock() and document that NULL means ENOMEM. Link: https://lkml.kernel.org/r/20250517003446.60260-1-alexei.starovoitov@gmail.com Signed-off-by: Alexei Starovoitov Acked-by: Vlastimil Babka Acked-by: Johannes Weiner Reviewed-by: Shakeel Butt Acked-by: Harry Yoo Cc: Andrii Nakryiko Cc: Kumar Kartikeya Dwivedi Cc: Michal Hocko Cc: Peter Zijlstra Cc: Sebastian Andrzej Siewior Cc: Steven Rostedt Signed-off-by: Andrew Morton

bpf: Add support to retrieve ref_ctr_offset for uprobe perf link

2025-05-09T20:01:07Z

Adding support to retrieve ref_ctr_offset for uprobe perf link, which got somehow omitted from the initial uprobe link info changes. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Acked-by: Yafang Shao Link: https://lore.kernel.org/bpf/20250509153539.779599-2-jolsa@kernel.org

bpf: Replace offsetof() with struct_size()

2025-05-01T17:37:35Z

Compared to offsetof(), struct_size() provides additional compile-time checks for structs with flexible arrays (e.g., __must_be_array()). No functional changes intended. Signed-off-by: Thorsten Blum Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250428210638.30219-2-thorsten.blum@linux.dev

bpf: Add namespace to BPF internal symbols

2025-04-25T16:21:23Z

Add namespace to BPF internal symbols used by light skeleton to prevent abuse and document with the code their allowed usage. Fixes: b1d18a7574d0 ("bpf: Extend sys_bpf commands for bpf_syscall programs.") Signed-off-by: Alexei Starovoitov Signed-off-by: Andrii Nakryiko Acked-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/bpf/20250425014542.62385-1-alexei.starovoitov@gmail.com

Merge tag 'bpf_try_alloc_pages' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2025-03-30T20:45:28Z

Pull bpf try_alloc_pages() support from Alexei Starovoitov: "The pull includes work from Sebastian, Vlastimil and myself with a lot of help from Michal and Shakeel. This is a first step towards making kmalloc reentrant to get rid of slab wrappers: bpf_mem_alloc, kretprobe's objpool, etc. These patches make page allocator safe from any context. Vlastimil kicked off this effort at LSFMM 2024: https://lwn.net/Articles/974138/ and we continued at LSFMM 2025: https://lore.kernel.org/all/CAADnVQKfkGxudNUkcPJgwe3nTZ=xohnRshx9kLZBTmR_E1DFEg@mail.gmail.com/ Why: SLAB wrappers bind memory to a particular subsystem making it unavailable to the rest of the kernel. Some BPF maps in production consume Gbytes of preallocated memory. Top 5 in Meta: 1.5G, 1.2G, 1.1G, 300M, 200M. Once we have kmalloc that works in any context BPF map preallocation won't be necessary. How: Synchronous kmalloc/page alloc stack has multiple stages going from fast to slow: cmpxchg16 -> slab_alloc -> new_slab -> alloc_pages -> rmqueue_pcplist -> __rmqueue, where rmqueue_pcplist was already relying on trylock. This set changes rmqueue_bulk/rmqueue_buddy to attempt a trylock and return ENOMEM if alloc_flags & ALLOC_TRYLOCK. It then wraps this functionality into try_alloc_pages() helper. We make sure that the logic is sane in PREEMPT_RT. End result: try_alloc_pages()/free_pages_nolock() are safe to call from any context. try_kmalloc() for any context with similar trylock approach will follow. It will use try_alloc_pages() when slab needs a new page. Though such try_kmalloc/page_alloc() is an opportunistic allocator, this design ensures that the probability of successful allocation of small objects (up to one page in size) is high. Even before we have try_kmalloc(), we already use try_alloc_pages() in BPF arena implementation and it's going to be used more extensively in BPF" * tag 'bpf_try_alloc_pages' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: mm: Fix the flipped condition in gfpflags_allow_spinning() bpf: Use try_alloc_pages() to allocate pages for bpf needs. mm, bpf: Use memcg in try_alloc_pages(). memcg: Use trylock to access memcg stock_lock. mm, bpf: Introduce free_pages_nolock() mm, bpf: Introduce try_alloc_pages() for opportunistic page allocation locking/local_lock: Introduce localtry_lock_t

bpf: Implement verifier support for rqspinlock

2025-03-19T15:03:06Z

Introduce verifier-side support for rqspinlock kfuncs. The first step is allowing bpf_res_spin_lock type to be defined in map values and allocated objects, so BTF-side is updated with a new BPF_RES_SPIN_LOCK field to recognize and validate. Any object cannot have both bpf_spin_lock and bpf_res_spin_lock, only one of them (and at most one of them per-object, like before) must be present. The bpf_res_spin_lock can also be used to protect objects that require lock protection for their kfuncs, like BPF rbtree and linked list. The verifier plumbing to simulate success and failure cases when calling the kfuncs is done by pushing a new verifier state to the verifier state stack which will verify the failure case upon calling the kfunc. The path where success is indicated creates all lock reference state and IRQ state (if necessary for irqsave variants). In the case of failure, the state clears the registers r0-r5, sets the return value, and skips kfunc processing, proceeding to the next instruction. When marking the return value for success case, the value is marked as 0, and for the failure case as [-MAX_ERRNO, -1]. Then, in the program, whenever user checks the return value as 'if (ret)' or 'if (ret < 0)' the verifier never traverses such branches for success cases, and would be aware that the lock is not held in such cases. We push the kfunc state in check_kfunc_call whenever rqspinlock kfuncs are invoked. We introduce a kfunc_class state to avoid mixing lock irqrestore kfuncs with IRQ state created by bpf_local_irq_save. With all this infrastructure, these kfuncs become usable in programs while satisfying all safety properties required by the kernel. Acked-by: Eduard Zingerman Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20250316040541.108729-24-memxor@gmail.com Signed-off-by: Alexei Starovoitov

bpf: Return prog btf_id without capable check

2025-03-17T20:45:12Z

Return prog's btf_id from bpf_prog_get_info_by_fd regardless of capable check. This patch enables scenario, when freplace program, running from user namespace, requires to query target prog's btf. Signed-off-by: Mykyta Yatsenko Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20250317174039.161275-3-mykyta.yatsenko5@gmail.com

bpf: BPF token support for BPF_BTF_GET_FD_BY_ID

2025-03-17T20:45:11Z

Currently BPF_BTF_GET_FD_BY_ID requires CAP_SYS_ADMIN, which does not allow running it from user namespace. This creates a problem when freplace program running from user namespace needs to query target program BTF. This patch relaxes capable check from CAP_SYS_ADMIN to CAP_BPF and adds support for BPF token that can be passed in attributes to syscall. Signed-off-by: Mykyta Yatsenko Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250317174039.161275-2-mykyta.yatsenko5@gmail.com

security: Propagate caller information in bpf hooks

2025-03-15T18:48:58Z

Certain bpf syscall subcommands are available for usage from both userspace and the kernel. LSM modules or eBPF gatekeeper programs may need to take a different course of action depending on whether or not a BPF syscall originated from the kernel or userspace. Additionally, some of the bpf_attr struct fields contain pointers to arbitrary memory. Currently the functionality to determine whether or not a pointer refers to kernel memory or userspace memory is exposed to the bpf verifier, but that information is missing from various LSM hooks. Here we augment the LSM hooks to provide this data, by simply passing a boolean flag indicating whether or not the call originated in the kernel, in any hook that contains a bpf_attr struct that corresponds to a subcommand that may be called from the kernel. Signed-off-by: Blaise Boscaccy Acked-by: Song Liu Acked-by: Paul Moore Link: https://lore.kernel.org/r/20250310221737.821889-2-bboscaccy@linux.microsoft.com Signed-off-by: Alexei Starovoitov