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Groups > linux.kernel > #1590139 > unrolled thread
| Started by | Arnd Bergmann <arnd@arndb.de> |
|---|---|
| First post | 2017-03-01 10:40 +0100 |
| Last post | 2017-03-01 16:30 +0100 |
| Articles | 2 on this page of 22 — 3 participants |
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Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Arnd Bergmann <arnd@arndb.de> - 2017-03-01 10:40 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Arnd Bergmann <arnd@arndb.de> - 2017-03-01 11:00 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Josh Poimboeuf <jpoimboe@redhat.com> - 2017-03-01 15:50 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Josh Poimboeuf <jpoimboe@redhat.com> - 2017-03-01 18:30 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Arnd Bergmann <arnd@arndb.de> - 2017-03-01 23:10 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Arnd Bergmann <arnd@arndb.de> - 2017-03-01 23:50 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Josh Poimboeuf <jpoimboe@redhat.com> - 2017-03-02 02:20 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Ingo Molnar <mingo@kernel.org> - 2017-03-02 07:40 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Ingo Molnar <mingo@kernel.org> - 2017-03-02 15:00 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Josh Poimboeuf <jpoimboe@redhat.com> - 2017-03-02 15:30 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Ingo Molnar <mingo@kernel.org> - 2017-03-02 15:50 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Josh Poimboeuf <jpoimboe@redhat.com> - 2017-03-02 15:10 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Arnd Bergmann <arnd@arndb.de> - 2017-03-03 00:20 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Josh Poimboeuf <jpoimboe@redhat.com> - 2017-03-03 01:00 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Arnd Bergmann <arnd@arndb.de> - 2017-03-03 10:30 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Arnd Bergmann <arnd@arndb.de> - 2017-03-03 16:40 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Arnd Bergmann <arnd@arndb.de> - 2017-03-01 16:30 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Josh Poimboeuf <jpoimboe@redhat.com> - 2017-03-02 19:40 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Arnd Bergmann <arnd@arndb.de> - 2017-03-03 00:00 +0100
Re: [PATCH] objtool: fix another gcc jump table detection issue Arnd Bergmann <arnd@arndb.de> - 2017-03-03 00:10 +0100
[PATCH] objtool: fix another gcc jump table detection issue Josh Poimboeuf <jpoimboe@redhat.com> - 2017-03-03 04:20 +0100
Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Josh Poimboeuf <jpoimboe@redhat.com> - 2017-03-01 16:30 +0100
Page 2 of 2 — ← Prev page 1 [2]
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Date | 2017-03-03 04:20 +0100 |
| Subject | [PATCH] objtool: fix another gcc jump table detection issue |
| Message-ID | <tgI1c-KT-23@gated-at.bofh.it> |
| In reply to | #1591531 |
Arnd Bergmann reported a (false positive) objtool warning:
drivers/infiniband/sw/rxe/rxe_resp.o: warning: objtool: rxe_responder()+0xfe: sibling call from callable instruction with changed frame pointer
The issue is in find_switch_table(). It tries to find a switch
statement's jump table by walking backwards from an indirect jump
instruction, looking for a relocation to the .rodata section. In this
case it stopped walking prematurely: the first .rodata relocation it
encountered was for a variable (resp_state_name) instead of a jump
table, so it just assumed there wasn't a jump table.
The fix is to ignore any .rodata relocation which refers to an ELF
object symbol. This works because the jump tables are anonymous and
have no symbols associated with them.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 3732710ff6f2 ("objtool: Improve rare switch jump table pattern detection")
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
tools/objtool/builtin-check.c | 15 ++++++++++++---
tools/objtool/elf.c | 12 ++++++++++++
tools/objtool/elf.h | 1 +
3 files changed, 25 insertions(+), 3 deletions(-)
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 5fc52ee..c2a8518 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -805,11 +805,20 @@ static struct rela *find_switch_table(struct objtool_file *file,
insn->jump_dest->offset > orig_insn->offset))
break;
+ /* look for a relocation which references .rodata */
text_rela = find_rela_by_dest_range(insn->sec, insn->offset,
insn->len);
- if (text_rela && text_rela->sym == file->rodata->sym)
- return find_rela_by_dest(file->rodata,
- text_rela->addend);
+ if (!text_rela || text_rela->sym != file->rodata->sym)
+ continue;
+
+ /*
+ * Make sure the .rodata address isn't associated with a
+ * symbol. gcc jump tables are anonymous data.
+ */
+ if (find_symbol_containing(file->rodata, text_rela->addend))
+ continue;
+
+ return find_rela_by_dest(file->rodata, text_rela->addend);
}
return NULL;
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 0d7983a..d897702 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -85,6 +85,18 @@ struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset)
return NULL;
}
+struct symbol *find_symbol_containing(struct section *sec, unsigned long offset)
+{
+ struct symbol *sym;
+
+ list_for_each_entry(sym, &sec->symbol_list, list)
+ if (sym->type != STT_SECTION &&
+ offset >= sym->offset && offset < sym->offset + sym->len)
+ return sym;
+
+ return NULL;
+}
+
struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset,
unsigned int len)
{
diff --git a/tools/objtool/elf.h b/tools/objtool/elf.h
index aa1ff65..731973e 100644
--- a/tools/objtool/elf.h
+++ b/tools/objtool/elf.h
@@ -79,6 +79,7 @@ struct elf {
struct elf *elf_open(const char *name);
struct section *find_section_by_name(struct elf *elf, const char *name);
struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
+struct symbol *find_symbol_containing(struct section *sec, unsigned long offset);
struct rela *find_rela_by_dest(struct section *sec, unsigned long offset);
struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset,
unsigned int len);
--
2.7.4
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| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Date | 2017-03-01 16:30 +0100 |
| Message-ID | <tgemt-4Vt-5@gated-at.bofh.it> |
| In reply to | #1590139 |
On Wed, Mar 01, 2017 at 10:34:42AM +0100, Arnd Bergmann wrote:
> On Tue, Oct 11, 2016 at 10:38 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> > On Tuesday, October 11, 2016 10:51:46 AM CEST Josh Poimboeuf wrote:
> >>
> >> 3) 0xFC244C03-config:
> >> drivers/scsi/fnic/fnic_main.o: warning: objtool: fnic_log_q_error() falls through to next function fnic_handle_link_event()
> >> drivers/scsi/snic/snic_res.o: warning: objtool: .text: unexpected end of section
> >>
> >> These look like another bad gcc bug which is truncating functions:
> >
> > Same bug for both of them?
>
> I ran into this one again today, after updating to the latest gcc-7.0.1:
>
> drivers/infiniband/sw/rxe/rxe_resp.o: warning: objtool:
> rxe_responder()+0xfe: sibling call from callable instruction with
> changed frame pointer
>
> Josh, did you get around to updating objtool the last time I reported it, or
> is it still the same problem? If this is a new variation, I can provide more
> details about the failure, otherwise I'll just ignore it for now.
This one should have been fixed with:
3732710ff6f2 ("objtool: Improve rare switch jump table pattern detection")
Can you attach the object file?
--
Josh
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