From: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx> 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. Sorry, this was due to my carelessness. Thanks. HATAYAMA, Daisuke
