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SubjectRe: [PATCH v5 7/8] vmcore: calculate vmcore file size from buffer size and total size of vmcore objects
On Tue, May 14, 2013 at 10:57:46AM +0900, HATAYAMA Daisuke wrote:
> The previous patches newly added holes before each chunk of memory and
> the holes need to be count in vmcore file size. There are two ways to
> count file size in such a way:
>
> 1) supporse p as a poitner to the last program header entry with
> PT_LOAD type, then roundup(p->p_offset + p->p_memsz, PAGE_SIZE), or
>
> 2) calculate sum of size of buffers for ELF header, program headers,
> ELF note segments and objects in vmcore_list.
>
> Although 1) is more direct and simpler than 2), 2) seems better in
> that it reflects internal object structure of /proc/vmcore. Thus, this
> patch changes get_vmcore_size_elf{64, 32} so that it calculates size
> in the way of 2).
>
> Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
> ---

Looks good to me.

Acked-by: Vivek Goyal <vgoyal@redhat.com>

Vivek

>
> fs/proc/vmcore.c | 40 ++++++++++++++++++----------------------
> 1 files changed, 18 insertions(+), 22 deletions(-)
>
> diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
> index eb7ff29..ad6da17 100644
> --- a/fs/proc/vmcore.c
> +++ b/fs/proc/vmcore.c
> @@ -210,36 +210,28 @@ static struct vmcore* __init get_new_element(void)
> return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
> }
>
> -static u64 __init get_vmcore_size_elf64(char *elfptr, size_t elfsz)
> +static u64 __init get_vmcore_size_elf64(size_t elfsz, size_t elfnotesegsz,
> + struct list_head *vc_list)
> {
> - int i;
> u64 size;
> - Elf64_Ehdr *ehdr_ptr;
> - Elf64_Phdr *phdr_ptr;
> + struct vmcore *m;
>
> - ehdr_ptr = (Elf64_Ehdr *)elfptr;
> - phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr));
> - size = elfsz;
> - for (i = 0; i < ehdr_ptr->e_phnum; i++) {
> - size += phdr_ptr->p_memsz;
> - phdr_ptr++;
> + size = elfsz + elfnotesegsz;
> + list_for_each_entry(m, vc_list, list) {
> + size += m->size;
> }
> return size;
> }
>
> -static u64 __init get_vmcore_size_elf32(char *elfptr, size_t elfsz)
> +static u64 __init get_vmcore_size_elf32(size_t elfsz, size_t elfnotesegsz,
> + struct list_head *vc_list)
> {
> - int i;
> u64 size;
> - Elf32_Ehdr *ehdr_ptr;
> - Elf32_Phdr *phdr_ptr;
> + struct vmcore *m;
>
> - ehdr_ptr = (Elf32_Ehdr *)elfptr;
> - phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr));
> - size = elfsz;
> - for (i = 0; i < ehdr_ptr->e_phnum; i++) {
> - size += phdr_ptr->p_memsz;
> - phdr_ptr++;
> + size = elfsz + elfnotesegsz;
> + list_for_each_entry(m, vc_list, list) {
> + size += m->size;
> }
> return size;
> }
> @@ -755,14 +747,18 @@ static int __init parse_crash_elf_headers(void)
> return rc;
>
> /* Determine vmcore size. */
> - vmcore_size = get_vmcore_size_elf64(elfcorebuf, elfcorebuf_sz);
> + vmcore_size = get_vmcore_size_elf64(elfcorebuf_sz,
> + elfnotesegbuf_sz,
> + &vmcore_list);
> } else if (e_ident[EI_CLASS] == ELFCLASS32) {
> rc = parse_crash_elf32_headers();
> if (rc)
> return rc;
>
> /* Determine vmcore size. */
> - vmcore_size = get_vmcore_size_elf32(elfcorebuf, elfcorebuf_sz);
> + vmcore_size = get_vmcore_size_elf32(elfcorebuf_sz,
> + elfnotesegbuf_sz,
> + &vmcore_list);
> } else {
> pr_warn("Warning: Core image elf header is not sane\n");
> return -EINVAL;


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