From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751452AbbAMIhw (ORCPT ); Tue, 13 Jan 2015 03:37:52 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:27518 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750981AbbAMIhv (ORCPT ); Tue, 13 Jan 2015 03:37:51 -0500 Message-ID: <54B4D925.3020906@huawei.com> Date: Tue, 13 Jan 2015 16:36:53 +0800 From: Wang Nan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.0.1 MIME-Version: 1.0 To: Jiri Olsa CC: , , , , , , , , , Subject: Re: [PATCH] perf: fix dwarf unwind using libunwind. References: <1421117677-51536-1-git-send-email-wangnan0@huawei.com> <20150113071059.GA32634@krava.brq.redhat.com> In-Reply-To: <20150113071059.GA32634@krava.brq.redhat.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.111.69.90] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020206.54B4D942.00C7,ss=1,re=0.001,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 6f15500137421ca8af6131aff662dd31 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/1/13 15:10, Jiri Olsa wrote: > On Tue, Jan 13, 2015 at 10:54:37AM +0800, Wang Nan wrote: > > SNIP > >> >> +static int elf_is_exec(int fd, const char *name) >> +{ >> + Elf *elf; >> + GElf_Ehdr ehdr; >> + int retval = 0; >> + >> + elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); >> + if (elf == NULL) >> + return 0; >> + if (gelf_getehdr(elf, &ehdr) == NULL) >> + goto out; >> + >> + retval = (ehdr.e_type == ET_EXEC); >> + >> +out: >> + elf_end(elf); >> + pr_debug("unwind: elf_is_exec(%s): %d\n", name, retval); >> + return retval; >> + >> +} > > yuou need to add stub for 'NO_LIBUNWIND_DEBUG_FRAME=1', otherwise: > > CC util/dwarf-aux.o > CC util/unwind-libunwind.o > util/unwind-libunwind.c:188:12: error: ‘elf_is_exec’ defined but not used [-Werror=unused-function] > static int elf_is_exec(int fd, const char *name) > ^ > cc1: all warnings being treated as errors > make[1]: *** [util/unwind-libunwind.o] Error 1 > make[1]: *** Waiting for unfinished jobs.... > make: *** [all] Error 2 > > jirka > Thanks. I haven't test NO_LIBUNWIND_DEBUG_FRAME=1 case. I found that it is possible to utilize map->dso->adjust_symbols for this propose so we don't need to introduce another function to check ehdr.e_type. However map->dso->adjust_symbols checks not only ET_EXEC but also ET_REL. What do you think? I'd like to check it and post another patch. >> + >> struct table_entry { >> u32 start_ip_offset; >> u32 fde_offset; >> @@ -322,8 +343,12 @@ find_proc_info(unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi, >> #ifndef NO_LIBUNWIND_DEBUG_FRAME >> /* Check the .debug_frame section for unwinding info */ >> if (!read_unwind_spec_debug_frame(map->dso, ui->machine, &segbase)) { >> + int fd = dso__data_fd(map->dso, ui->machine); >> + int is_exec = elf_is_exec(fd, map->dso->name); >> + unw_word_t base = is_exec ? 0 : map->start; >> + >> memset(&di, 0, sizeof(di)); >> - if (dwarf_find_debug_frame(0, &di, ip, 0, map->dso->name, >> + if (dwarf_find_debug_frame(0, &di, ip, base, map->dso->name, >> map->start, map->end)) >> return dwarf_search_unwind_table(as, ip, &di, pi, >> need_unwind_info, arg); >> -- >> 1.8.4 >>