Re: [PATCH v2 05/20] vmcore: round up buffer size of ELF headers by PAGE_SIZE

Yanfei Zhang
2013-03-06T15:52:06Z

2013/3/2 HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>:
> To satisfy mmap() page-size boundary requirement, round up buffer size
> of ELF headers by PAGE_SIZE. The resulting value becomes offset of ELF
~~~~~~~~~~~
ELF header? or ELF program headers?

> note segments and it's assigned in unique PT_NOTE program header
> entry.
>
> Also, some part that assumes past ELF headers' size is replaced by
> this new rounded-up value.

Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>

>
> Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
> ---
>
> fs/proc/vmcore.c | 16 ++++++++--------
> 1 files changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
> index 1b02d01..c511cf4 100644
> --- a/fs/proc/vmcore.c
> +++ b/fs/proc/vmcore.c
> @@ -340,7 +340,7 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
> phdr.p_flags = 0;
> note_off = ehdr_ptr->e_phoff +
> (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
> - phdr.p_offset = note_off;
> + phdr.p_offset = roundup(note_off, PAGE_SIZE);
> phdr.p_vaddr = phdr.p_paddr = 0;
> phdr.p_filesz = phdr.p_memsz = phdr_sz;
> phdr.p_align = 0;
> @@ -353,6 +353,7 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
> /* Modify e_phnum to reflect merged headers. */
> ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
>
> + *elfsz = roundup(*elfsz, PAGE_SIZE);
> out:
> return 0;
> }
> @@ -449,7 +450,7 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
> phdr.p_flags = 0;
> note_off = ehdr_ptr->e_phoff +
> (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
> - phdr.p_offset = note_off;
> + phdr.p_offset = roundup(note_off, PAGE_SIZE);
> phdr.p_vaddr = phdr.p_paddr = 0;
> phdr.p_filesz = phdr.p_memsz = phdr_sz;
> phdr.p_align = 0;
> @@ -462,6 +463,7 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
> /* Modify e_phnum to reflect merged headers. */
> ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
>
> + *elfsz = roundup(*elfsz, PAGE_SIZE);
> out:
> return 0;
> }
> @@ -482,9 +484,8 @@ static int __init process_ptload_program_headers_elf64(char *elfptr,
> phdr_ptr = (Elf64_Phdr*)(elfptr + ehdr_ptr->e_phoff); /* PT_NOTE hdr */
>
> /* First program header is PT_NOTE header. */
> - vmcore_off = ehdr_ptr->e_phoff +
> - (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
> - phdr_ptr->p_memsz; /* Note sections */
> + vmcore_off = phdr_ptr->p_offset + roundup(phdr_ptr->p_memsz,
> + PAGE_SIZE);
>
> for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
> if (phdr_ptr->p_type != PT_LOAD)
> @@ -519,9 +520,8 @@ static int __init process_ptload_program_headers_elf32(char *elfptr,
> phdr_ptr = (Elf32_Phdr*)(elfptr + ehdr_ptr->e_phoff); /* PT_NOTE hdr */
>
> /* First program header is PT_NOTE header. */
> - vmcore_off = ehdr_ptr->e_phoff +
> - (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) +
> - phdr_ptr->p_memsz; /* Note sections */
> + vmcore_off = phdr_ptr->p_offset + roundup(phdr_ptr->p_memsz,
> + PAGE_SIZE);
>
> for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
> if (phdr_ptr->p_type != PT_LOAD)
>
> --
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