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2026-06-05bpf: NUL-terminate replaced sysctl valueDawei Feng
When writing to sysctls, proc_sys_call_handler() guarantees that the buffer passed to proc handlers is NUL-terminated. If bpf_sysctl_set_new_value() replaces the pending sysctl value, it can hand a replacement buffer directly to proc handlers. However, the helper currently copies only buf_len bytes into that buffer without appending a NUL terminator, leaving downstream parsers vulnerable to out-of-bounds access. Fix this by appending a '\0' after the replaced value to restore the expected sysctl semantics. Since the helper already rejects buf_len greater than PAGE_SIZE - 1, there is always room for the extra byte. Reproduced in a QEMU x86_64 guest booted with KASAN while exercising the sysctl replacement path with a cgroup/sysctl BPF program. The reproducer targets `/proc/sys/net/core/flow_limit_cpu_bitmap`, fills the original user write buffer with non-zero bytes, and overrides the sysctl value so the replacement buffer lacks a terminating NUL. Under that setup, the pre-fix kernel reported: BUG: KASAN: slab-out-of-bounds in strnchrnul+0x72/0x90 Read of size 1 at addr ffff88800de57000 by task repro_patch3/66 CPU: 0 UID: 0 PID: 66 Comm: repro_patch3 Not tainted 7.1.0-rc3-00269-g8370ca1f87cc #6 PREEMPT(lazy) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x68/0xa0 print_report+0xcb/0x5e0 ? __virt_addr_valid+0x21d/0x3f0 ? strnchrnul+0x72/0x90 ? strnchrnul+0x72/0x90 kasan_report+0xca/0x100 ? strnchrnul+0x72/0x90 strnchrnul+0x72/0x90 bitmap_parse+0x37/0x2e0 flow_limit_cpu_sysctl+0xc6/0x840 ? __pfx_flow_limit_cpu_sysctl+0x10/0x10 ? __kvmalloc_node_noprof+0x5ba/0x870 proc_sys_call_handler+0x31d/0x480 ? __pfx_proc_sys_call_handler+0x10/0x10 ? selinux_file_permission+0x39f/0x500 ? lock_is_held_type+0x9e/0x120 vfs_write+0x98e/0x1000 ... </TASK> The buggy address is located 0 bytes to the right of allocated 4096-byte region [ffff88800de56000, ffff88800de57000) With this fix applied, rerunning the same sysctl-targeted path yields no corresponding KASAN reports. Signed-off-by: Zilin Guan <zilin@seu.edu.cn> Signed-off-by: Dawei Feng <dawei.feng@seu.edu.cn> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20260603105317.944304-2-dawei.feng@seu.edu.cn Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05bpf: Check tail zero of bpf_prog_infoLeon Hwang
Since there're 4 bytes padding at the end of struct bpf_prog_info, they won't be checked by bpf_check_uarg_tail_zero(). pahole -C bpf_prog_info ./vmlinux struct bpf_prog_info { ... __u32 attach_btf_obj_id; /* 220 4 */ __u32 attach_btf_id; /* 224 4 */ /* size: 232, cachelines: 4, members: 38 */ /* sum members: 224 */ /* sum bitfield members: 1 bits, bit holes: 1, sum bit holes: 31 bits */ /* padding: 4 */ /* forced alignments: 9 */ /* last cacheline: 40 bytes */ } __attribute__((__aligned__(8))); If a future kernel extension adds a new 4-byte field, older userspace programs allocating this structure on the stack might inadvertently pass uninitialized stack garbage into the new field, permanently breaking backward compatibility. -- sashiko [1] Fix it by changing sizeof(info) to offsetofend(struct bpf_prog_info, attach_btf_id). And, add "__u32 :32" to the tail of struct bpf_prog_info. [1] https://lore.kernel.org/bpf/20260513224823.6494FC19425@smtp.kernel.org/ Fixes: aba64c7da983 ("bpf: Add verified_insns to bpf_prog_info and fdinfo") Acked-by: Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by: Leon Hwang <leon.hwang@linux.dev> Link: https://lore.kernel.org/r/20260605155249.20772-3-leon.hwang@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05bpf: Check tail zero of bpf_map_infoLeon Hwang
Since there're 4 bytes padding at the end of struct bpf_map_info, they won't be checked by bpf_check_uarg_tail_zero(). pahole -C bpf_map_info ./vmlinux struct bpf_map_info { ... __u64 hash __attribute__((__aligned__(8))); /* 88 8 */ __u32 hash_size; /* 96 4 */ /* size: 104, cachelines: 2, members: 18 */ /* padding: 4 */ /* forced alignments: 1 */ /* last cacheline: 40 bytes */ } __attribute__((__aligned__(8))); If a future kernel extension adds a new 4-byte field, older userspace programs allocating this structure on the stack might inadvertently pass uninitialized stack garbage into the new field, permanently breaking backward compatibility. -- sashiko [1] Fix it by changing sizeof(info) to offsetofend(struct bpf_map_info, hash_size). And, add "__u32 :32" to the tail of struct bpf_map_info. [1] https://lore.kernel.org/bpf/20260513224823.6494FC19425@smtp.kernel.org/ Fixes: ea2e6467ac36 ("bpf: Return hashes of maps in BPF_OBJ_GET_INFO_BY_FD") Acked-by: Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by: Leon Hwang <leon.hwang@linux.dev> Link: https://lore.kernel.org/r/20260605155249.20772-2-leon.hwang@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05bpf: Clear rb node linkage when freeing bpf_rb_rootKaitao Cheng
bpf_rb_root_free() detaches the root by copying the current rb_root_cached and then replacing the live root with RB_ROOT_CACHED. It then walks the copied root and drops each object contained in the tree. This leaves the rb node state intact while dropping the object. If the object is refcounted and survives the drop, its bpf_rb_node_kern still contains an owner pointer to the freed root and stale rb tree linkage. If a later bpf_rb_root allocation reuses the same address, bpf_rbtree_remove() can incorrectly pass the owner check and call rb_erase_cached() on a node whose rb pointers belong to the old tree. Mirror the list draining behavior by marking nodes as busy while the root is being detached, then clear the rb node and release the owner before dropping the containing object. This makes surviving nodes unowned and safe to reject from remove or accept for a later add. Fixes: 9c395c1b99bd ("bpf: Add basic bpf_rb_{root,node} support") Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20260605094143.5509-1-kaitao.cheng@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05bpf: Remove WARN_ON_ONCE in check_ids()Amery Hung
check_ids() warned when it ran out of idmap slots, assuming this was impossible because the slots are bounded by the number of registers and stack slots. That assumption no longer holds: referenced dynptrs acquire an intermediate reference that lives in refs[] but is not backed by any register or stack slot [0], so a program can accumulate more reference ids than the idmap can hold and exhaust it. Exhaustion is fine for verification correctness. check_ids() already returns false, which makes the states compare as not equivalent and prevents unsound pruning. The only effect of the WARN_ON_ONCE() is log noise, or a panic under panic_on_warn. Drop the warning and keep returning false. [0] 308c7a0ae885 ("bpf: Refactor object relationship tracking and fix dynptr UAF bug") Signed-off-by: Amery Hung <ameryhung@gmail.com> Link: https://lore.kernel.org/r/20260605202056.1780352-5-ameryhung@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05bpf: Compare parent_id in refsafe() for REF_TYPE_PTRAmery Hung
refsafe() compared each reference's id and type but not its parent_id, so two states whose PTR references differ only in the parent object they were derived from could be wrongly treated as equivalent and pruned. Fix it by checking parent_id too. Fixes: 308c7a0ae885 ("bpf: Refactor object relationship tracking and fix dynptr UAF bug") Signed-off-by: Amery Hung <ameryhung@gmail.com> Link: https://lore.kernel.org/r/20260605202056.1780352-4-ameryhung@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05bpf: Check acquire_reference() error for "__ref" struct_ops argumentsAmery Hung
When acquiring references for struct_ops program arguments tagged with "__ref", the return value of acquire_reference() was stored directly into u32 ctx_arg_info[i].ref_id without checking for failure. acquire_reference() returns -ENOMEM when acquire_reference_state() fails to allocate, so the error was silently stored as a ref_id instead of aborting verification. Fix it by checking the return. Fixes: a687df2008f6 ("bpf: Support getting referenced kptr from struct_ops argument") Signed-off-by: Amery Hung <ameryhung@gmail.com> Link: https://lore.kernel.org/r/20260605202056.1780352-3-ameryhung@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05bpf: Fix dead error check on acquire_reference() in check_kfunc_callAmery Hung
acquire_reference() returns a signed int that may be a negative errno but was converted to unsigned, which makes the subsequent error check deadcode. Fix it by declaring 'id' as int so the error path is taken correctly. Fixes: 308c7a0ae885 ("bpf: Refactor object relationship tracking and fix dynptr UAF bug") Acked-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Amery Hung <ameryhung@gmail.com> Link: https://lore.kernel.org/r/20260605202056.1780352-2-ameryhung@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05Merge tag 'probes-fixes-v7.1-rc6' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing/probes fix from Masami Hiramatsu: "Fix the eprobe event parser to point error position correctly" * tag 'probes-fixes-v7.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing/probes: Point the error offset correctly for eprobe argument error
2026-06-05bpf: Replace scratch PTE atomically when allocating arena pagesTejun Heo
apply_range_set_cb() maps the pages for a new arena allocation and returned -EBUSY when the target PTE was already populated. Kernel-fault recovery leaves the per-arena scratch page in unallocated arena PTEs, so a later bpf_arena_alloc_pages() over such a page hits that -EBUSY, and every subsequent allocation of it fails the same way. Allocation must install the real page over scratch instead. Overwriting the scratch PTE in place is a valid->valid change, which arm64 forbids without break-before-make. Route through an invalid entry instead: ptep_try_set() fills only a none slot, so the PTE goes scratch->none->page. On finding scratch, clear it and flush_tlb_before_set() before retrying. The new flush_tlb_before_set() is a no-op except on arches like arm64 that need the break-before-make TLB invalidate. The loop also copes with a concurrent fault re-scratching the slot. Arches without ptep_try_set() never install the scratch page, so keep the must-be-empty check and set_pte_at() for them. Fixes: dc11a4dba246 ("bpf: Recover arena kernel faults with scratch page") Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: David Hildenbrand <david@kernel.org> Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20260601183728.1800490-1-tj@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05bpf: Reject fragmented frames in devmapZhao Zhang
Devmap broadcast redirects clone the packet for all but the last destination. For native XDP, that clone path copies only the linear xdp_frame data, while fragmented frames keep skb_shared_info in tailroom outside the linear area. Cloning such a frame leaves XDP_FLAGS_HAS_FRAGS set but without valid frag metadata, and the later free path can interpret uninitialized tail data as skb_shared_info, leading to an out-of-bounds access during frame return. Reject fragmented native XDP frames in dev_map_enqueue_clone(). Add the same restriction to the generic XDP clone path in dev_map_redirect_clone(). Generic XDP represents fragmented packets as nonlinear skbs, and rejecting them here keeps clone-based broadcast support aligned between native and generic XDP. Fixes: e624d4ed4aa8 ("xdp: Extend xdp_redirect_map with broadcast support") Cc: stable@kernel.org Reported-by: Yuan Tan <yuantan098@gmail.com> Reported-by: Zhengchuan Liang <zcliangcn@gmail.com> Reported-by: Xin Liu <bird@lzu.edu.cn> Assisted-by: Codex:GPT-5.4 Signed-off-by: Zhao Zhang <zzhan461@ucr.edu> Signed-off-by: Ren Wei <n05ec@lzu.edu.cn> Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/r/21c2d153dd25603d359069a02bf06779b51f6423.1780385378.git.zzhan461@ucr.edu Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05bpf: Reject registration of duplicated kfuncSong Chen
Search for duplicated kfunc in btf_vmlinux and btf_modules before a kernel module attempts to register a kfunc. If kfunc would shadow existing kfunc then pr_err() and reject module loading. Reviewed-by: Yonghong Song <yonghong.song@linux.dev> Signed-off-by: Song Chen <chensong_2000@126.com> Link: https://lore.kernel.org/r/20260603091910.7212-1-chensong_2000@126.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05bpf: Optimize word-sized keys for resizable hashtableMykyta Yatsenko
Specialize the lookup/update/delete paths for keys whose size matches sizeof(long) (4 bytes on 32-bit, 8 bytes on 64-bit). A static-const rhashtable_params lets the compiler inline a custom XOR-fold hashfn and a single-word equality cmpfn, eliminating the indirect jhash dispatch. The same hashfn and cmpfn are installed into rhashtable's stored params at rhashtable_init time, so the rehash worker, slow-path inserts, and rhashtable_next_key() all agree with the inlined fast paths. The seq_file BPF iterator uses rhashtable_walk_* and is unaffected. Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Link: https://lore.kernel.org/r/20260605-rhash-v7-7-5b8e05f8630d@meta.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05bpf: Allow special fields in resizable hashtabMykyta Yatsenko
Add support for timers, workqueues, task work, spin locks and kptrs. Without this, users needing deferred callbacks, BPF_F_LOCK, or refcounted kernel pointers in a dynamically-sized map have no option - fixed-size htab is the only map supporting these field types. Resizable hashtab should offer the same capability. kptr semantics under in-place updates are identical to array map. Properly clean up BTF record fields on element delete and map teardown by wiring up bpf_obj_free_fields through a memory allocator destructor, matching the pattern used by htab for non-prealloc maps. Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Link: https://lore.kernel.org/r/20260605-rhash-v7-6-5b8e05f8630d@meta.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05bpf: Implement iteration ops for resizable hashtabMykyta Yatsenko
Implement get_next_key, batch lookup/lookup-and-delete, for_each_map_elem callback, and the seq_file BPF iterator for BPF_MAP_TYPE_RHASH. get_next_key() and batch use rhashtable_next_key() — stateless, matches the syscall UAPI shape (no kernel-side iterator state). get_next_key falls back to the first key when prev_key was concurrently deleted (matches htab semantics). Batch reports cursor loss as -EAGAIN so userspace can distinguish it from end-of-iteration (-ENOENT) and restart from NULL. The seq_file BPF iterator uses rhashtable_walk_* instead. It runs only from read() syscall context, so the walker's spin_lock is safe, and seq_file's per-fd state lets the walker handle rehash correctly (retry on -EAGAIN) for stronger coverage than the stateless API can provide. Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Link: https://lore.kernel.org/r/20260605-rhash-v7-5-5b8e05f8630d@meta.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05bpf: Implement resizable hashmap basic functionsMykyta Yatsenko
Use rhashtable_lookup_likely() for lookups, rhashtable_remove_fast() for deletes, and rhashtable_lookup_get_insert_fast() for inserts. Updates modify values in place under RCU rather than allocating a new element and swapping the pointer (as regular htab does). This trades read consistency for performance: concurrent readers may see partial updates. BPF_F_LOCK support and special-field handling (timers, kptrs, etc.) follow in a later commit. Initialize rhashtable with bpf_mem_alloc element cache. Require BPF_F_NO_PREALLOC. Limit max_entries to 2^31. Free elements via rhashtable_free_and_destroy(). Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Link: https://lore.kernel.org/r/20260605-rhash-v7-4-5b8e05f8630d@meta.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05cgroup/dmem: introduce a peak fileThadeu Lima de Souza Cascardo
Just like we have memory.peak, introduce a dmem.peak, which uses the page_counter support for that. For now, make it read-only. This allows for memory usage monitoring without polling dmem.current when the information needed is the maximum device memory used. That can be used for capacity planning, such that dmem.max can be properly setup for a given workload. It can also be used for debugging to determine whether a given workload would have caused eviction or system memory use. Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com> Reviewed-by: Michal Koutný <mkoutny@suse.com> Reviewed-by: Maarten Lankhorst <dev@lankhorst.se> Link: https://patch.msgid.link/20260514-dmem_peak-v3-1-b64ce5d3ac38@igalia.com Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
2026-06-04kcov: use WRITE_ONCE() for selftest mode storesKarl Mehltretter
The KCOV selftest enables coverage by setting current->kcov_mode to KCOV_MODE_TRACE_PC without installing a coverage area. If an interrupt records coverage in that window, the access should fault and expose the bug. When building for QEMU raspi0 (Raspberry Pi Zero, ARMv6, CONFIG_CPU_V6K=y, CONFIG_CURRENT_POINTER_IN_TPIDRURO=y) with GCC 13.3.0, the store that enables the mode is removed. The generated kcov_init() code only stores zero after the wait loop: mrc 15, 0, r3, cr13, cr0, {3} str r4, [r3, #2028] where r4 is zero. There is no store of KCOV_MODE_TRACE_PC before the loop, so the selftest reports success without exercising coverage. Use WRITE_ONCE() for the temporary mode stores. With the same compiler and config, kcov_init() contains the intended mode store: mov r3, #2 mrc 15, 0, r2, cr13, cr0, {3} str r3, [r2, #2028] Now that the KCOV selftest is actually executed, it may expose KCOV instrumentation issues depending on the kernel config. That is expected for a selftest that was intended to catch coverage from interrupt paths. Link: https://lore.kernel.org/20260526114715.38280-1-kmehltretter@gmail.com Fixes: 6cd0dd934b03 ("kcov: Add interrupt handling self test") Assisted-by: Codex:gpt-5 Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Kees Cook <kees@kernel.org> Cc: Marco Elver <elver@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-06-04bpf: Take mmap_lock in zap_pages()Alexei Starovoitov
zap_vma_range() requires the owning mm's mmap_lock to be held. Taking mmap_read_lock under arena->lock would AB-BA against arena_vm_close() and arena_map_mmap(), both of which run with mmap_write_lock held and then acquire arena->lock. Instead drop arena->lock, mmget_not_zero() the vma's mm, take mmap_read_lock, and re-resolve the vma via find_vma() since it may have been unmapped or replaced while waiting. Track processed vmls with a per-call generation in vml->zap_gen and serialize zap_pages() callers with a new arena->zap_mutex so concurrent callers on different uaddr ranges do not mark each other's vmls processed before the zap is done. Reported-by: David Hildenbrand <david@kernel.org> Fixes: 317460317a02 ("bpf: Introduce bpf_arena.") Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com> Link: https://lore.kernel.org/r/20260528222014.38980-1-alexei.starovoitov@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-04bpf: clean up btf_scan_decl_tags()Matt Bobrowski
Refactor the newly introduced btf_scan_decl_tags() to improve readability and maintainability. The current implementation uses a manual if-else chain and a magic number offset to strip the "arg:" prefix from declaration tags. Replace the if-else logic with a table-driven approach using a static const array. This separates the tag data from the scanning logic, making the helper more extensible for future tags. Additionally, replace the magic number '4' with a sizeof-based calculation on the prefix string to ensure the offset remains synchronized with the search key. Finally, optimize the loop by moving the is_global check to the top of the block. This allows the verifier to fail-fast on static subprograms without performing unnecessary BTF string and type lookups. Signed-off-by: Matt Bobrowski <mattbobrowski@google.com> Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com> Link: https://lore.kernel.org/r/20260603201822.770596-1-mattbobrowski@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-04module: decompress: check return value of module_extend_max_pages()Andrii Kuchmenko
module_extend_max_pages() calls kvrealloc() internally and returns -ENOMEM on allocation failure. The return value is never checked. If the initial allocation fails, info->pages remains NULL and info->max_pages remains 0. Subsequent calls to module_get_next_page() will attempt to dynamically grow the array by calling module_extend_max_pages(info, 0) since info->used_pages is 0. This results in kvrealloc(NULL, 0) returning ZERO_SIZE_PTR, which is treated as a success, leading to a dereference of ZERO_SIZE_PTR and a kernel oops. Fix: add the missing error check after module_extend_max_pages() and return immediately on failure. This matches the pattern used by every other kvrealloc() caller in the module loading path. Fixes: b1ae6dc41eaa ("module: add in-kernel support for decompressing") Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Andrii Kuchmenko <capyenglishlite@gmail.com> Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org> [Sami: Corrected the analysis in the commit message.] Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
2026-06-04Merge drm/drm-next into drm-xe-nextThomas Hellström
Backmerging to bring in a build error fix to drm-xe-next. Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
2026-06-04timers/migration: Fix livelock in tmigr_handle_remote_up()Amit Matityahu
tmigr_handle_remote_cpu() skips timer_expire_remote() when cpu == smp_processor_id(), assuming the local softirq path already handled this CPU's timers. This assumption is wrong because jiffies can advance after the handling of the CPU's global timers in run_timer_base(BASE_GLOBAL) and before tmigr_handle_remote() evaluates the expiry times. As a consequence a timer which expires after the CPU local timer wheel advanced and becomes expired in the remote handling is ignored and the callback is never invoked and removed from the timer wheel. What's worse is that fetch_next_timer_interrupt_remote() keeps reporting it as expired, and the event is re-queued with expires == now on each iteration. The goto-again loop spins indefinitely. Fix this by calling timer_expire_remote() unconditionally. That's minimal overhead for the common case as __run_timer_base() returns immediately if there is nothing to expire in the local wheel. [ tglx: Amend change log and add a comment ] Fixes: 7ee988770326 ("timers: Implement the hierarchical pull model") Reported-by: Alon Kariv <alonka@amazon.com> Signed-off-by: Amit Matityahu <amitmat@amazon.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260603170139.33628-1-amitmat@amazon.com
2026-06-03sched_ext: Add scx_arena_to_kaddr() / scx_kaddr_to_arena()Tejun Heo
Translating between a BPF-arena pointer and its kernel-side address is just an add or subtract of the arena's kern_vm start. More such translations are coming, so cache that start on scx_sched as @arena_kern_base at arena attach and wrap both directions. Convert the existing open-coded subtraction in scx_call_op_set_cpumask(). Signed-off-by: Tejun Heo <tj@kernel.org>
2026-06-04perf: Reveal PMU type in fdinfoChun-Tse Shao
It gives useful info on knowing which PMUs are reserved by this process. Also add config which would be useful. Testing cycles: $ ./perf stat -e cycles & $ cat /proc/`pidof perf`/fdinfo/3 pos: 0 flags: 02000002 mnt_id: 16 ino: 3081 perf_event_attr.type: 0 perf_event_attr.config: 0x0 perf_event_attr.config1: 0x0 perf_event_attr.config2: 0x0 perf_event_attr.config3: 0x0 perf_event_attr.config4: 0x0 Testing L1-dcache-load-misses: $ ./perf stat -e L1-dcache-load-misses & $ cat /proc/`pidof perf`/fdinfo/3 pos: 0 flags: 02000002 mnt_id: 16 ino: 1072 perf_event_attr.type: 3 perf_event_attr.config: 0x10000 perf_event_attr.config1: 0x0 perf_event_attr.config2: 0x0 perf_event_attr.config3: 0x0 perf_event_attr.config4: 0x0 Signed-off-by: Chun-Tse Shao <ctshao@google.com> Assisted-by: Gemini:gemini-3.1-pro-preview Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ian Rogers <irogers@google.com> Link: https://patch.msgid.link/20260602181349.3969429-1-ctshao@google.com
2026-06-04timekeeping: Add clocksource read_snapshot() method and hw_cycles to snapshotDavid Woodhouse
Add a read_snapshot() callback to struct clocksource which returns the derived clocksource value while also providing the underlying hardware counter reading and the related clocksource ID. This allows ktime_get_snapshot_id() to populate new hw_cycles and hw_csid fields in struct system_time_snapshot. For clocksources that are derived from an underlying counter (e.g., Hyper-V TSC page scales TSC to 10MHz, kvmclock scales TSC to 1GHz), this provides atomic access to both the derived value needed for timekeeping calculations, and the raw hardware counter needed by consumers like KVM's master clock and the vmclock PTP driver. [ tglx: Reworked it slightly ] Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Assisted-by: Kiro:claude-opus-4.6-1m Link: https://patch.msgid.link/20260526230635.136914-1-dwmw2@infradead.org Link: https://patch.msgid.link/20260529195558.202568489@kernel.org
2026-06-04timekeeping: Add support for AUX clock cross timestampingThomas Gleixner
Now that all prerequisites are in place add the final support for AUX clocks in get_device_system_crosststamp(), which enables the PTP layer to support hardware cross timestamps with a new IOTCL. Signed-off-by: Thomas Gleixner <tglx@kernel.org> Tested-by: Arthur Kiyanovski <akiyano@amazon.com> Reviewed-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Link: https://patch.msgid.link/20260529195558.097464513@kernel.org
2026-06-04timekeeping: Prepare for cross timestamps on arbitrary clock IDsThomas Gleixner
PTP device system crosstime stamps support only CLOCK_REALTIME, which is meaningless for AUX clocks. The PTP core hands in the clock ID already, so prepare the core code to honor it. - Add a new sys_systime field to struct system_device_crosststamp which aliases the sys_realtime field. Once all users are converted sys_realtime can be removed. - Prepare get_device_system_crosststamp() and the related code for it by switching to sys_systime and providing the initial changes to utilize different time keepers. No functional change intended. Signed-off-by: Thomas Gleixner <tglx@kernel.org> Tested-by: David Woodhouse <dwmw@amazon.co.uk> Tested-by: Arthur Kiyanovski <akiyano@amazon.com> Reviewed-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Link: https://patch.msgid.link/20260529195557.846634842@kernel.org
2026-06-04timekeeping: Add system_counterval_t to struct system_device_crosststampThomas Gleixner
An upcoming extension to the PTP IOCTL requires to return the system counter value and the clocksource ID to user space. get_device_system_crosststamp() has this information already. Extend struct system_device_crosststamp with a system_counterval_t member and fill in the data. Signed-off-by: Thomas Gleixner <tglx@kernel.org> Tested-by: David Woodhouse <dwmw@amazon.co.uk> Tested-by: Arthur Kiyanovski <akiyano@amazon.com> Reviewed-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Link: https://patch.msgid.link/20260529195557.429406675@kernel.org
2026-06-04timekeeping: Add CLOCK_AUX support for ktime_get_snapshot_id()Thomas Gleixner
Now that all users are converted it's possible to enable snapshotting of CLOCK_AUX time. The underlying clocksource is the same as for all other CLOCK variants. Signed-off-by: Thomas Gleixner <tglx@kernel.org> Tested-by: Arthur Kiyanovski <akiyano@amazon.com> Reviewed-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Link: https://patch.msgid.link/20260529195557.380601005@kernel.org
2026-06-04timekeeping: Remove system_time_snapshot::real/boot/rawThomas Gleixner
All users are converted over to ktime_get_snapshot_id() and system_time_snapshot::systime and ::monoraw. Remove the leftovers. Signed-off-by: Thomas Gleixner <tglx@kernel.org> Tested-by: David Woodhouse <dwmw@amazon.co.uk> Tested-by: Arthur Kiyanovski <akiyano@amazon.com> Reviewed-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Link: https://patch.msgid.link/20260529195557.330029635@kernel.org
2026-06-03sched_ext: Make scx_bpf_kick_cid() return s32Tejun Heo
Switch scx_bpf_kick_cid() from void to s32 so future cap enforcement can surface failures. cid interface is introduced in this cycle and has no external users, so the ABI change is safe. Subsequent patches will add -EPERM returns when the calling sub-sched lacks the required cap on the target cid. v2: Return scx_cid_to_cpu()'s errno instead of -EINVAL. (Andrea) Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Andrea Righi <arighi@nvidia.com>
2026-06-03sched_ext: Add scx_cmask_test() and scx_cmask_for_each_cid()Tejun Heo
Add single-bit test and iterator over set cids in an scx_cmask. v2: Bound scx_cmask_for_each_cid() to the active span. (sashiko AI) Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Andrea Righi <arighi@nvidia.com>
2026-06-03sched_ext: Order single-cid cmask helpers as (cid, mask)Tejun Heo
__scx_cmask_set(), __scx_cmask_contains() and __scx_cmask_word() take the cmask first and the cid second. The kernel's bit and cpumask predicates put the index first: test_bit(nr, addr), cpumask_test_cpu(cpu, mask). Reorder the cmask helpers to (cid, mask) for consistency, ahead of new single-cid ops added next. Mask-level ops (and/or/andnot/copy/subset/intersects) keep (dst, src). Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Andrea Righi <arighi@nvidia.com>
2026-06-03locking/rtmutex: Skip remove_waiter() when waiter is not enqueuedDavidlohr Bueso
syzbot triggered the following splat in remove_waiter() via FUTEX_CMP_REQUEUE_PI: KASAN: null-ptr-deref in range [0x0000000000000a88-0x0000000000000a8f] class_raw_spinlock_constructor remove_waiter+0x159/0x1200 kernel/locking/rtmutex.c:1561 rt_mutex_start_proxy_lock+0x103/0x120 futex_requeue+0x10e4/0x20d0 __x64_sys_futex+0x34f/0x4d0 task_blocks_on_rt_mutex() does not arm the waiter upon deadlock detection, leaving waiter->task nil, where 3bfdc63936dd ("rtmutex: Use waiter::task instead of current in remove_waiter()") made this fatal. Furthermore, rt_mutex_start_proxy_lock() should not be calling into remove_waiter() upon a successfully grabbing the rtmutex. 1a1fb985f2e2 ("futex: Handle early deadlock return correctly"), moved the remove_waiter() out of __rt_mutex_start_proxy_lock() (where 'ret' was only ever 0 or < 0) into the wrapper. Tighten this check to account for try_to_take_rt_mutex(). Fixes: 3bfdc63936dd ("rtmutex: Use waiter::task instead of current in remove_waiter()") Reported-by: syzbot+78147abe6c524f183ee9@syzkaller.appspotmail.com Signed-off-by: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Cc: stable@vger.kernel.org Closes: https://lore.kernel.org/all/69f114ac.050a0220.ac8b.0003.GAE@google.com/ Link: https://patch.msgid.link/20260507112913.1019537-1-dave@stgolabs.net
2026-06-03liveupdate: Remove limit on the number of files per sessionPasha Tatashin
To remove the fixed limit on the number of preserved files per session, transition the file metadata serialization from a single contiguous memory block to a chain of linked blocks. Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Link: https://patch.msgid.link/20260603154402.468928-11-pasha.tatashin@soleen.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-06-03liveupdate: Remove limit on the number of sessionsPasha Tatashin
Currently, the number of LUO sessions is limited by a fixed number of pre-allocated pages for serialization (16 pages, allowing for ~819 sessions). This limitation is problematic if LUO is used to support things such as systemd file descriptor store, and would be used not just as VM memory but to save other states on the machine. Remove this limit by transitioning to a linked-block approach for session metadata serialization. Instead of a single contiguous block, session metadata is now stored in a chain of 16-page blocks. Each block starts with a header containing the physical address of the next block and the number of session entries in the current block. Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Link: https://patch.msgid.link/20260603154402.468928-10-pasha.tatashin@soleen.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-06-03liveupdate: defer session block allocation and physical address settingPasha Tatashin
Currently, luo_session_setup_outgoing() allocates the session block and sets its physical address in the header immediately. With upcoming dynamic block-based session management, this makes the first block different from the rest. Move the allocation to where it is first needed. Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Link: https://patch.msgid.link/20260603154402.468928-9-pasha.tatashin@soleen.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-06-03kho: add support for linked-block serializationPasha Tatashin
Introduce a linked-block serialization mechanism for state handover. Previously, LUO used contiguous memory blocks for serializing sessions and files, which imposed limits on the total number of items that could be preserved across a live update. This commit adds the infrastructure for a more flexible, block-based approach where serialized data is stored in a chain of linked blocks. This is a generic KHO serialization block infrastructure that can be used by multiple subsystems. Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Link: https://patch.msgid.link/20260603154402.468928-8-pasha.tatashin@soleen.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-06-03liveupdate: Extract luo_session_deserialize_one helperPasha Tatashin
Extract the logic for deserializing single entries for sessions into separate helper functions. In preparation to a linked-block serialization for sessions. This is a pure code movement, no other changes intended. Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Link: https://patch.msgid.link/20260603154402.468928-7-pasha.tatashin@soleen.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-06-03liveupdate: Extract luo_file_deserialize_one helperPasha Tatashin
Extract the logic for deserializing single entries for files into separate helper functions. In preparation to a linked-block serialization for files. This is a pure code movement, no other changes intended. Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Link: https://patch.msgid.link/20260603154402.468928-6-pasha.tatashin@soleen.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-06-03liveupdate: register luo_ser as KHO subtreePasha Tatashin
Entirely remove the LUO FDT wrapper since the FDT only carries the compatible string and the pointer to the centralized struct luo_ser. Instead, register the struct luo_ser via the KHO raw subtree API, placing the compatibility string inside the structure itself. Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Link: https://patch.msgid.link/20260603154402.468928-5-pasha.tatashin@soleen.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-06-03liveupdate: centralize state management into struct luo_serPasha Tatashin
Transition the LUO to ABI v2, which centralizes state management into a single struct luo_ser header. Previously, LUO state was spread across multiple FDT properties and subnodes. ABI v2 simplifies this by placing all core state, including the liveupdate number and physical addresses for sessions and FLB headers into a centralized struct luo_ser. Note that this change introduces a semantic difference: the sessions and FLB serialization formats are no longer completely independent of the core LUO. Their metadata (such as physical addresses for sessions and FLB headers) is now coupled to and managed via the centralized struct luo_ser. Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Link: https://patch.msgid.link/20260603154402.468928-4-pasha.tatashin@soleen.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-06-03liveupdate: avoid mixing cleanup guards with goto in luo_session_retrieve_fdPasha Tatashin
Refactoring luo_session_retrieve_fd() to avoid mixing automated cleanup-style guards with goto-based resource release, which is not recommended under the Linux kernel coding style. Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Link: https://patch.msgid.link/20260603154402.468928-3-pasha.tatashin@soleen.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-06-03liveupdate: change file_set->count type to u64 for type safetyPasha Tatashin
This improves type safety and aligns the in-memory file_set->count with the serialized count type. It avoids potential truncation or sign conversion mismatch issues. Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Link: https://patch.msgid.link/20260603154402.468928-2-pasha.tatashin@soleen.com Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
2026-06-03Merge tag 'cgroup-for-7.1-rc6-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fixes from Tejun Heo: "One cpuset fix and a maintenance update, both low-risk: - Fix cpuset partition CPU accounting under sibling CPU exclusion that could produce wrong CPU assignments and trigger scheduling-domain warnings. Includes selftests. - Update an email address in MAINTAINERS" * tag 'cgroup-for-7.1-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup/cpuset: Change Ridong's email cgroup/cpuset: Add test cases for sibling CPU exclusion on partition update cgroup/cpuset: Use effective_xcpus in partcmd_update add/del mask calculation
2026-06-03Merge tag 'sched_ext-for-7.1-rc6-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext Pull sched_ext fixes from Tejun Heo: "Two low-risk fixes: - Drop a spurious warning that can fire during cgroup migration while a sched_ext scheduler is loaded - Fix a drgn-based debug script that broke after scheduler state moved into a per-scheduler struct" * tag 'sched_ext-for-7.1-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: sched_ext: Don't warn on NULL cgrp_moving_from in scx_cgroup_move_task() tools/sched_ext: Fix scx_show_state per-scheduler state reads
2026-06-03dma-debug: fix physical address retrieval in debug_dma_sync_sg_for_deviceLi RongQing
In debug_dma_sync_sg_for_device(), when iterating over a scatterlist, the debug entry population mistakenly uses the head of the scatterlist 'sg' to fetch the physical address via sg_phys(), instead of using the current iterator variable 's'. This causes dma-debug to track the physical address of the very first scatterlist entry for all subsequent entries in the list. Fix this by passing the correct loop iterator 's' to sg_phys() Fixes: 9d4f645a1fd49ee ("dma-debug: store a phys_addr_t in struct dma_debug_entry") Signed-off-by: Li RongQing <lirongqing@baidu.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Link: https://lore.kernel.org/r/20260603123708.1665-1-lirongqing@baidu.com
2026-06-03rv: Use 0 to check preemption enabled in opidGabriele Monaco
Tracepoint handlers no longer run with preemption disabled by default since a46023d5616 ("tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast"), the opid monitor should now count 1 in the preemption count as preemption disabled. Change the rule for preempt_off to preempt > 0. Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260601153840.124372-11-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
2026-06-03rv: Add automatic cleanup handlers for per-task HA monitorsGabriele Monaco
Hybrid automata monitors may start timers, depending on the model, these may remain active on an exiting task and cause false positives or even access freed memory. Add an enable/disable hook in the HA code, currently only populated by the per-task handler for registration and deregistration. This hooks to the sched_process_exit event and ensures the timer is stopped for every exiting task. The handler is enabled automatically but may be disabled, for instance if the monitor uses the event for another purpose (but should still manually ensure timers are stopped). Fixes: f5587d1b6ec9 ("rv: Add Hybrid Automata monitor type") Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://lore.kernel.org/r/20260601153840.124372-8-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>