From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932240AbbIYP2p (ORCPT ); Fri, 25 Sep 2015 11:28:45 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:40645 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755917AbbIYP2o (ORCPT ); Fri, 25 Sep 2015 11:28:44 -0400 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Adrian Hunter , Jiri Olsa , stable@kernel.org, Arnaldo Carvalho de Melo Subject: [PATCH 3/3] perf tools: Fix copying of /proc/kcore Date: Fri, 25 Sep 2015 12:28:38 -0300 Message-Id: <1443194918-5867-4-git-send-email-acme@kernel.org> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1443194918-5867-1-git-send-email-acme@kernel.org> References: <1443194918-5867-1-git-send-email-acme@kernel.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Adrian Hunter A copy of /proc/kcore containing the kernel text can be made to the buildid cache. e.g. perf buildid-cache -v -k /proc/kcore To workaround objdump limitations, a copy is also made when annotating against /proc/kcore. The copying process stops working from libelf about v1.62 onwards (the problem was found with v1.63). The cause is that a call to gelf_getphdr() in kcore__add_phdr() fails because additional validation has been added to gelf_getphdr(). The use of gelf_getphdr() is a misguided attempt to get default initialization of the Gelf_Phdr structure. That should not be necessary because every member of the Gelf_Phdr structure is subsequently assigned. So just remove the call to gelf_getphdr(). Similarly, a call to gelf_getehdr() in gelf_kcore__init() can be removed also. Committer notes: Note to stable@kernel.org, from Adrian in the cover letter for this patchkit: The "Fix copying of /proc/kcore" problem goes back to v3.13 if you think it is important enough for stable. Signed-off-by: Adrian Hunter Cc: Jiri Olsa Cc: stable@kernel.org Link: http://lkml.kernel.org/r/1443089122-19082-3-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/symbol-elf.c | 35 +++++++++++++---------------------- 1 file changed, 13 insertions(+), 22 deletions(-) diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index f78ea3dc4c08..475d88d0a1c9 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -1271,8 +1271,6 @@ out_close: static int kcore__init(struct kcore *kcore, char *filename, int elfclass, bool temp) { - GElf_Ehdr *ehdr; - kcore->elfclass = elfclass; if (temp) @@ -1289,9 +1287,7 @@ static int kcore__init(struct kcore *kcore, char *filename, int elfclass, if (!gelf_newehdr(kcore->elf, elfclass)) goto out_end; - ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr); - if (!ehdr) - goto out_end; + memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr)); return 0; @@ -1348,23 +1344,18 @@ static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count) static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset, u64 addr, u64 len) { - GElf_Phdr gphdr; - GElf_Phdr *phdr; - - phdr = gelf_getphdr(kcore->elf, idx, &gphdr); - if (!phdr) - return -1; - - phdr->p_type = PT_LOAD; - phdr->p_flags = PF_R | PF_W | PF_X; - phdr->p_offset = offset; - phdr->p_vaddr = addr; - phdr->p_paddr = 0; - phdr->p_filesz = len; - phdr->p_memsz = len; - phdr->p_align = page_size; - - if (!gelf_update_phdr(kcore->elf, idx, phdr)) + GElf_Phdr phdr = { + .p_type = PT_LOAD, + .p_flags = PF_R | PF_W | PF_X, + .p_offset = offset, + .p_vaddr = addr, + .p_paddr = 0, + .p_filesz = len, + .p_memsz = len, + .p_align = page_size, + }; + + if (!gelf_update_phdr(kcore->elf, idx, &phdr)) return -1; return 0; -- 2.1.0