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Message-Id: <1443194918-5867-4-git-send-email-acme@kernel.org>
Date: Fri, 25 Sep 2015 12:28:38 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Ingo Molnar <mingo@...nel.org>
Cc: linux-kernel@...r.kernel.org,
Adrian Hunter <adrian.hunter@...el.com>,
Jiri Olsa <jolsa@...hat.com>, stable@...nel.org,
Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 3/3] perf tools: Fix copying of /proc/kcore
From: Adrian Hunter <adrian.hunter@...el.com>
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@...nel.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 <adrian.hunter@...el.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: stable@...nel.org
Link: http://lkml.kernel.org/r/1443089122-19082-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
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
--
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