From 2b97956af60810cd382b86b9ce9aea421b889861 Mon Sep 17 00:00:00 2001 From: Nuoqi Gui Date: Fri, 4 Sep 2026 12:41:55 +0200 Subject: selftests/bpf: Test rhtab kptr cancellation semantics Resizable hash-map updates and deletions must not perform full special-field destruction in their caller context. In particular, a referenced kptr must remain attached to the allocation until the memory allocator destructor can release it safely. Add separate coverage for both affected paths. The update test stores a task kptr, replaces the ordinary value bytes with BPF_EXIST, and verifies that the kptr survived. The delete test removes an element and exchanges its kptr through the still-valid map-value pointer before the allocation is reclaimed. Both cases observe a NULL kptr when rhtab uses bpf_obj_free_fields(). They recover and release the reference after rhtab switches to cancellation semantics. Signed-off-by: Nuoqi Gui [ kkd: Split update and delete coverage and rewrote the commit log ] Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904104203.345917-5-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/asm-generic/cacheflush.h | 127 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 127 insertions(+) create mode 100644 include/asm-generic/cacheflush.h (limited to 'include/asm-generic/cacheflush.h') diff --git a/include/asm-generic/cacheflush.h b/include/asm-generic/cacheflush.h new file mode 100644 index 000000000..7ee8a179d --- /dev/null +++ b/include/asm-generic/cacheflush.h @@ -0,0 +1,127 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_CACHEFLUSH_H +#define _ASM_GENERIC_CACHEFLUSH_H + +#include + +struct mm_struct; +struct vm_area_struct; +struct page; +struct address_space; + +/* + * The cache doesn't need to be flushed when TLB entries change when + * the cache is mapped to physical memory, not virtual memory + */ +#ifndef flush_cache_all +static inline void flush_cache_all(void) +{ +} +#endif + +#ifndef flush_cache_mm +static inline void flush_cache_mm(struct mm_struct *mm) +{ +} +#endif + +#ifndef flush_cache_dup_mm +static inline void flush_cache_dup_mm(struct mm_struct *mm) +{ +} +#endif + +#ifndef flush_cache_range +static inline void flush_cache_range(struct vm_area_struct *vma, + unsigned long start, + unsigned long end) +{ +} +#endif + +#ifndef flush_cache_page +static inline void flush_cache_page(struct vm_area_struct *vma, + unsigned long vmaddr, + unsigned long pfn) +{ +} +#endif + +#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE +static inline void flush_dcache_page(struct page *page) +{ +} + +#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0 +#endif + +#ifndef flush_dcache_mmap_lock +static inline void flush_dcache_mmap_lock(struct address_space *mapping) +{ +} +#endif + +#ifndef flush_dcache_mmap_unlock +static inline void flush_dcache_mmap_unlock(struct address_space *mapping) +{ +} +#endif + +#ifndef flush_icache_range +static inline void flush_icache_range(unsigned long start, unsigned long end) +{ +} +#endif + +#ifndef flush_icache_user_range +#define flush_icache_user_range flush_icache_range +#endif + +#ifndef flush_icache_user_page +static inline void flush_icache_user_page(struct vm_area_struct *vma, + struct page *page, + unsigned long addr, int len) +{ +} +#endif + +#ifndef flush_cache_vmap +static inline void flush_cache_vmap(unsigned long start, unsigned long end) +{ +} +#endif + +#ifndef flush_cache_vmap_early +static inline void flush_cache_vmap_early(unsigned long start, unsigned long end) +{ +} +#endif + +#ifndef flush_cache_vunmap +static inline void flush_cache_vunmap(unsigned long start, unsigned long end) +{ +} +#endif + +#ifndef copy_to_user_page +#define copy_to_user_page(vma, page, vaddr, dst, src, len) \ + do { \ + instrument_copy_to_user((void __user *)dst, src, len); \ + memcpy(dst, src, len); \ + flush_icache_user_page(vma, page, vaddr, len); \ + } while (0) +#endif + + +#ifndef copy_from_user_page +#define copy_from_user_page(vma, page, vaddr, dst, src, len) \ + do { \ + instrument_copy_from_user_before(dst, (void __user *)src, \ + len); \ + memcpy(dst, src, len); \ + instrument_copy_from_user_after(dst, (void __user *)src, len, \ + 0); \ + } while (0) +#endif + +#endif /* _ASM_GENERIC_CACHEFLUSH_H */ -- cgit v1.3.1