diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 96370e3e3687..cf956edf05ef 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -2444,26 +2444,8 @@ static int elf_core_dump(struct coredump_params *cprm) for (i = 0, vma = first_vma(current, gate_vma); vma != NULL; vma = next_vma(vma, gate_vma)) { - unsigned long addr; - unsigned long end; - - end = vma->vm_start + vma_filesz[i++]; - - for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) { - struct page *page; - int stop; - - page = get_dump_page(addr); - if (page) { - void *kaddr = kmap(page); - stop = !dump_emit(cprm, kaddr, PAGE_SIZE); - kunmap(page); - put_page(page); - } else - stop = !dump_skip(cprm, PAGE_SIZE); - if (stop) - goto end_coredump; - } + if (!dump_user_range(cprm, vma->vm_start, vma_filesz[i++])) + goto end_coredump; } dump_truncate(cprm); diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index a53f83830986..76e8c0defdc8 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -1534,21 +1534,9 @@ static bool elf_fdpic_dump_segments(struct coredump_params *cprm) if (!maydump(vma, cprm->mm_flags)) continue; - for (addr = vma->vm_start; addr < vma->vm_end; - addr += PAGE_SIZE) { - bool res; - struct page *page = get_dump_page(addr); - if (page) { - void *kaddr = kmap(page); - res = dump_emit(cprm, kaddr, PAGE_SIZE); - kunmap(page); - put_page(page); - } else { - res = dump_skip(cprm, PAGE_SIZE); - } - if (!res) - return false; - } + if (!dump_user_range(cprm, vma->vm_start, + vma->vma_end - vma->vm_start)) + return false; } return true; } diff --git a/fs/coredump.c b/fs/coredump.c index 5e24c06092c9..6042d15acd51 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -876,6 +876,40 @@ int dump_skip(struct coredump_params *cprm, size_t nr) } EXPORT_SYMBOL(dump_skip); +#ifdef CONFIG_ELF_CORE +int dump_user_range(struct coredump_params *cprm, unsigned long start, + unsigned long len) +{ + unsigned long addr; + + for (addr = start; addr < start + len; addr += PAGE_SIZE) { + struct page *page; + int stop; + + /* + * To avoid having to allocate page tables for virtual address + * ranges that have never been used yet, and also to make it + * easy to generate sparse core files, use a helper that returns + * NULL when encountering an empty page table entry that would + * otherwise have been filled with the zero page. + */ + page = get_dump_page(addr); + if (page) { + void *kaddr = kmap(page); + + stop = !dump_emit(cprm, kaddr, PAGE_SIZE); + kunmap(page); + put_page(page); + } else { + stop = !dump_skip(cprm, PAGE_SIZE); + } + if (stop) + return 0; + } + return 1; +} +#endif + int dump_align(struct coredump_params *cprm, int align) { unsigned mod = cprm->pos & (align - 1); diff --git a/include/linux/coredump.h b/include/linux/coredump.h index 7a899e83835d..f0b71a74d0bc 100644 --- a/include/linux/coredump.h +++ b/include/linux/coredump.h @@ -16,6 +16,8 @@ extern int dump_skip(struct coredump_params *cprm, size_t nr); extern int dump_emit(struct coredump_params *cprm, const void *addr, int nr); extern int dump_align(struct coredump_params *cprm, int align); extern void dump_truncate(struct coredump_params *cprm); +int dump_user_range(struct coredump_params *cprm, unsigned long start, + unsigned long len); #ifdef CONFIG_COREDUMP extern void do_coredump(const kernel_siginfo_t *siginfo); #else