From: "Eric W. Biederman" <ebied...@xmission.com> Subject: Re: [PATCH v3 17/21] vmcore: check NT_VMCORE_PAD as a mark indicating the end of ELF note buffer Date: Tue, 19 Mar 2013 14:11:51 -0700
> HATAYAMA Daisuke <d.hatay...@jp.fujitsu.com> writes: > >> Modern kernel marks the end of ELF note buffer with NT_VMCORE_PAD type >> note in order to make the buffer satisfy mmap()'s page-size boundary >> requirement. This patch makes finishing reading each buffer if the >> note type now being read is NT_VMCORE_PAD type. > > Ick. Even with a pad header you can mark the end with an empty header, > and my memory may be deceiving me but I believe an empty header is > specified by the ELF ABI docs. > > Beyond which I don't quite see the point of any of this as all of these > headers need to be combined into a single note section before being > presented to user space. Though this patch might get unecessary later, I cannot find part explaining necessity of marking end of ELF segmetns with an empty header in ELF spec. For example: gabi http://www.sco.com/developers/gabi/latest/ch5.pheader.html#note_section AMD64 http://www.x86-64.org/documentation/abi.pdf But still there's possibility of another particular spec that says necessity of empty header. Also, it's possible to get size of a whole part of ELF note segments from p_memsz or p_filesz, and gdb and binutils are reading the note segments until reaching the size. Thanks. HATAYAMA, Daisuke -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
