On Mon, Mar 11, 2013 at 09:31:41AM +0900, HATAYAMA Daisuke wrote: > From: Zhang Yanfei <zhangyanfei at cn.fujitsu.com> > Subject: Re: [PATCH v2 01/20] vmcore: refer to e_phoff member explicitly > Date: Sun, 10 Mar 2013 14:46:31 +0800 > > > ? 2013?03?05? 15:35, Zhang Yanfei ??: > >> ? 2013?03?02? 16:35, HATAYAMA Daisuke ??: > <cut> > > > > One minor suggestion. > > > > Previously, when the code assumes program headers are following immediately > > the ELF header, it uses > > > > elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr); > > > > to calculate the size of ELF header and ELF program headers > > > > This patch avoids the assumption, and uses ehdr.e_phoff to get the program > > headers' address. But it will read unrelated contents into elfcorebuf if > > program headers are not following immediately the ELF header. So could the > > code be: > > > > elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr); > > addr = elfcorehdr_addr + ehdr.e_phoff; > > memcpy(elfcorebuf, &ehdr, sizeof(Elf64_Ehdr)); > > read_from_oldmem(elfcorebuf + sizeof(Elf64_Ehdr), elfcorebuf_sz - > > sizeof(Elf64_Ehdr), &addr, 0); > > (Elf64_Ehdr *)elfcorebuf->e_phoff = sizeof(Elf64_Ehdr); > > Thanks. This is not minor suggestion. This is critical. My code is > completely broken. On ELF, segments and headers other than ELF header > can occur in any positions. This means program header table can occur > after segments. So, on terabyte systems, e_phoff can be more than > terabytes. Agreed. It is safer to not copy al the bits till e_phoff. Thanks Vivek
