From: Daisuke HATAYAMA <d.hatayama@xxxxxxxxxxxxxx> By the next patch, elf_core_dump() and elf_fdpic_core_dump() will support extended numbering and so will produce the corefiles with section header table in a special case. The problem is the process of writing a file header offset of the section header table into e_shoff field of the ELF header. ELF header is positioned at the beginning of the corefile, while section header at the end. So, we need to take which of the following ways: 1. Seek backward to retry writing operation for ELF header after writing process for a whole part 2. Make offset calculation process and writing process totally sequential The clause 1. is not always possible: one cannot assume that file system supports seek function. Consider the no_llseek case. Therefore, this patch adopts the clause 2. Signed-off-by: Daisuke HATAYAMA <d.hatayama@xxxxxxxxxxxxxx> Cc: "Luck, Tony" <tony.luck@xxxxxxxxx> Cc: Jeff Dike <jdike@xxxxxxxxxxx> Cc: David Howells <dhowells@xxxxxxxxxx> Cc: Greg Ungerer <gerg@xxxxxxxxxxxx> Cc: Roland McGrath <roland@xxxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Andi Kleen <andi@xxxxxxxxxxxxxx> Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> Cc: <linux-arch@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/binfmt_elf.c | 27 ++++++++++++++++----------- fs/binfmt_elf_fdpic.c | 29 ++++++++++++++++------------- 2 files changed, 32 insertions(+), 24 deletions(-) diff -puN fs/binfmt_elf.c~elf-coredump-make-offset-calculation-process-and-writing-process-explicit fs/binfmt_elf.c --- a/fs/binfmt_elf.c~elf-coredump-make-offset-calculation-process-and-writing-process-explicit +++ a/fs/binfmt_elf.c @@ -1856,6 +1856,7 @@ static int elf_core_dump(struct coredump loff_t offset = 0, dataoff, foffset; unsigned long mm_flags; struct elf_note_info info; + struct elf_phdr *phdr4note = NULL; /* * We no longer stop all VM operations. @@ -1898,28 +1899,22 @@ static int elf_core_dump(struct coredump fs = get_fs(); set_fs(KERNEL_DS); - size += sizeof(*elf); - if (size > cprm->limit || !dump_write(cprm->file, elf, sizeof(*elf))) - goto end_coredump; - offset += sizeof(*elf); /* Elf header */ offset += (segs + 1) * sizeof(struct elf_phdr); /* Program headers */ foffset = offset; /* Write notes phdr entry */ { - struct elf_phdr phdr; size_t sz = get_note_info_size(&info); sz += elf_coredump_extra_notes_size(); - fill_elf_note_phdr(&phdr, sz, offset); - offset += sz; - - size += sizeof(phdr); - if (size > cprm->limit - || !dump_write(cprm->file, &phdr, sizeof(phdr))) + phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL); + if (!phdr4note) goto end_coredump; + + fill_elf_note_phdr(phdr4note, sz, offset); + offset += sz; } dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE); @@ -1931,6 +1926,15 @@ static int elf_core_dump(struct coredump */ mm_flags = current->mm->flags; + size += sizeof(*elf); + if (size > cprm->limit || !dump_write(cprm->file, elf, sizeof(*elf))) + goto end_coredump; + + size += sizeof(*phdr4note); + if (size > cprm->limit + || !dump_write(cprm->file, phdr4note, sizeof(*phdr4note))) + goto end_coredump; + /* Write program headers for segments dump */ for (vma = first_vma(current, gate_vma); vma != NULL; vma = next_vma(vma, gate_vma)) { @@ -2004,6 +2008,7 @@ end_coredump: cleanup: free_note_info(&info); + kfree(phdr4note); kfree(elf); out: return has_dumped; diff -puN fs/binfmt_elf_fdpic.c~elf-coredump-make-offset-calculation-process-and-writing-process-explicit fs/binfmt_elf_fdpic.c --- a/fs/binfmt_elf_fdpic.c~elf-coredump-make-offset-calculation-process-and-writing-process-explicit +++ a/fs/binfmt_elf_fdpic.c @@ -1600,6 +1600,7 @@ static int elf_fdpic_core_dump(struct co int thread_status_size = 0; elf_addr_t *auxv; unsigned long mm_flags; + struct elf_phdr *phdr4note = NULL; /* * We no longer stop all VM operations. @@ -1706,18 +1707,12 @@ static int elf_fdpic_core_dump(struct co fs = get_fs(); set_fs(KERNEL_DS); - size += sizeof(*elf); - if (size > cprm->limit - || !dump_write(cprm->file, elf, sizeof(*elf))) - goto end_coredump; - offset += sizeof(*elf); /* Elf header */ offset += (segs+1) * sizeof(struct elf_phdr); /* Program headers */ foffset = offset; /* Write notes phdr entry */ { - struct elf_phdr phdr; int sz = 0; for (i = 0; i < numnote; i++) @@ -1725,13 +1720,12 @@ static int elf_fdpic_core_dump(struct co sz += thread_status_size; - fill_elf_note_phdr(&phdr, sz, offset); - offset += sz; - - size += sizeof(phdr); - if (size > cprm->limit - || !dump_write(cprm->file, &phdr, sizeof(phdr))) + phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL); + if (!phdr4note) goto end_coredump; + + fill_elf_note_phdr(phdr4note, sz, offset); + offset += sz; } /* Page-align dumped data */ @@ -1744,6 +1738,15 @@ static int elf_fdpic_core_dump(struct co */ mm_flags = current->mm->flags; + size += sizeof(*elf); + if (size > cprm->limit || !dump_write(cprm->file, elf, sizeof(*elf))) + goto end_coredump; + + size += sizeof(*phdr4note); + if (size > cprm->limit + || !dump_write(cprm->file, phdr4note, sizeof(*phdr4note))) + goto end_coredump; + /* write program headers for segments dump */ for (vma = current->mm->mmap; vma; vma = vma->vm_next) { struct elf_phdr phdr; @@ -1815,7 +1818,7 @@ cleanup: list_del(tmp); kfree(list_entry(tmp, struct elf_thread_status, list)); } - + kfree(phdr4note); kfree(elf); kfree(prstatus); kfree(psinfo); _ -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html