* [PATCH] objtool: Fix object file corruption
@ 2017-09-15 7:17 Josh Poimboeuf
2017-09-15 8:44 ` [tip:core/urgent] " tip-bot for Josh Poimboeuf
2017-09-15 9:37 ` tip-bot for Josh Poimboeuf
0 siblings, 2 replies; 3+ messages in thread
From: Josh Poimboeuf @ 2017-09-15 7:17 UTC (permalink / raw)
To: Ingo Molnar; +Cc: Arnd Bergmann, linux-kernel
Arnd Bergmann reported that a randconfig build was failing with the
following link error:
built-in.o: member arch/x86/kernel/time.o in archive is not an object
It turns out the link failed because the time.o file had been corrupted
by objtool:
nm: arch/x86/kernel/time.o: File format not recognized
In certain rare cases, when a .o file's ORC table is very small, the
.data section size doesn't change because it's page aligned. Because
all the existing sections haven't changed size, libelf doesn't detect
any section header changes, and so it doesn't update the section header
table properly. Instead it writes junk in the section header entries
for the new ORC sections.
Make sure libelf properly updates the section header table by setting
the ELF_F_DIRTY flag in the top level elf struct.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 627fce14809b ("objtool: Add ORC unwind table generation")
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
tools/objtool/elf.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 6e9f980a7d26..780d02af957d 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -561,6 +561,7 @@ int elf_write(struct elf *elf)
struct section *sec;
Elf_Scn *s;
+ /* Update section headers for changed sections: */
list_for_each_entry(sec, &elf->sections, list) {
if (sec->changed) {
s = elf_getscn(elf->elf, sec->idx);
@@ -568,13 +569,17 @@ int elf_write(struct elf *elf)
WARN_ELF("elf_getscn");
return -1;
}
- if (!gelf_update_shdr (s, &sec->sh)) {
+ if (!gelf_update_shdr(s, &sec->sh)) {
WARN_ELF("gelf_update_shdr");
return -1;
}
}
}
+ /* Make sure the new section header entries get updated properly. */
+ elf_flagelf(elf->elf, ELF_C_SET, ELF_F_DIRTY);
+
+ /* Write all changes to the file. */
if (elf_update(elf->elf, ELF_C_WRITE) < 0) {
WARN_ELF("elf_update");
return -1;
--
2.13.5
^ permalink raw reply related [flat|nested] 3+ messages in thread* [tip:core/urgent] objtool: Fix object file corruption
2017-09-15 7:17 [PATCH] objtool: Fix object file corruption Josh Poimboeuf
@ 2017-09-15 8:44 ` tip-bot for Josh Poimboeuf
2017-09-15 9:37 ` tip-bot for Josh Poimboeuf
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot for Josh Poimboeuf @ 2017-09-15 8:44 UTC (permalink / raw)
To: linux-tip-commits
Cc: arnd, mingo, torvalds, hpa, peterz, linux-kernel, tglx, dzickus,
jpoimboe
Commit-ID: 3eed2fa7cb2118234cdc89fb6b2bef82b0c9ca81
Gitweb: http://git.kernel.org/tip/3eed2fa7cb2118234cdc89fb6b2bef82b0c9ca81
Author: Josh Poimboeuf <jpoimboe@redhat.com>
AuthorDate: Fri, 15 Sep 2017 02:17:11 -0500
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 15 Sep 2017 10:30:31 +0200
objtool: Fix object file corruption
Arnd Bergmann reported that a randconfig build was failing with the
following link error:
built-in.o: member arch/x86/kernel/time.o in archive is not an object
It turns out the link failed because the time.o file had been corrupted
by objtool:
nm: arch/x86/kernel/time.o: File format not recognized
In certain rare cases, when a .o file's ORC table is very small, the
.data section size doesn't change because it's page aligned. Because
all the existing sections haven't changed size, libelf doesn't detect
any section header changes, and so it doesn't update the section header
table properly. Instead it writes junk in the section header entries
for the new ORC sections.
Make sure libelf properly updates the section header table by setting
the ELF_F_DIRTY flag in the top level elf struct.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 627fce14809b ("objtool: Add ORC unwind table generation")
Link: http://lkml.kernel.org/r/e650fd0f2d8a209d1409a9785deb101fdaed55fb.1505459813.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
tools/objtool/elf.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index b4cd8bc..2446015 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -563,6 +563,7 @@ int elf_write(struct elf *elf)
struct section *sec;
Elf_Scn *s;
+ /* Update section headers for changed sections: */
list_for_each_entry(sec, &elf->sections, list) {
if (sec->changed) {
s = elf_getscn(elf->elf, sec->idx);
@@ -570,13 +571,17 @@ int elf_write(struct elf *elf)
WARN_ELF("elf_getscn");
return -1;
}
- if (!gelf_update_shdr (s, &sec->sh)) {
+ if (!gelf_update_shdr(s, &sec->sh)) {
WARN_ELF("gelf_update_shdr");
return -1;
}
}
}
+ /* Make sure the new section header entries get updated properly. */
+ elf_flagelf(elf->elf, ELF_C_SET, ELF_F_DIRTY);
+
+ /* Write all changes to the file. */
if (elf_update(elf->elf, ELF_C_WRITE) < 0) {
WARN_ELF("elf_update");
return -1;
^ permalink raw reply related [flat|nested] 3+ messages in thread* [tip:core/urgent] objtool: Fix object file corruption
2017-09-15 7:17 [PATCH] objtool: Fix object file corruption Josh Poimboeuf
2017-09-15 8:44 ` [tip:core/urgent] " tip-bot for Josh Poimboeuf
@ 2017-09-15 9:37 ` tip-bot for Josh Poimboeuf
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot for Josh Poimboeuf @ 2017-09-15 9:37 UTC (permalink / raw)
To: linux-tip-commits
Cc: arnd, hpa, peterz, jpoimboe, linux-kernel, tglx, mingo, torvalds
Commit-ID: 97dab2ae7e8473a821f72a039ead0f36b12ba22d
Gitweb: http://git.kernel.org/tip/97dab2ae7e8473a821f72a039ead0f36b12ba22d
Author: Josh Poimboeuf <jpoimboe@redhat.com>
AuthorDate: Fri, 15 Sep 2017 02:17:11 -0500
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 15 Sep 2017 11:31:57 +0200
objtool: Fix object file corruption
Arnd Bergmann reported that a randconfig build was failing with the
following link error:
built-in.o: member arch/x86/kernel/time.o in archive is not an object
It turns out the link failed because the time.o file had been corrupted
by objtool:
nm: arch/x86/kernel/time.o: File format not recognized
In certain rare cases, when a .o file's ORC table is very small, the
.data section size doesn't change because it's page aligned. Because
all the existing sections haven't changed size, libelf doesn't detect
any section header changes, and so it doesn't update the section header
table properly. Instead it writes junk in the section header entries
for the new ORC sections.
Make sure libelf properly updates the section header table by setting
the ELF_F_DIRTY flag in the top level elf struct.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 627fce14809b ("objtool: Add ORC unwind table generation")
Link: http://lkml.kernel.org/r/e650fd0f2d8a209d1409a9785deb101fdaed55fb.1505459813.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
tools/objtool/elf.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index b4cd8bc..2446015 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -563,6 +563,7 @@ int elf_write(struct elf *elf)
struct section *sec;
Elf_Scn *s;
+ /* Update section headers for changed sections: */
list_for_each_entry(sec, &elf->sections, list) {
if (sec->changed) {
s = elf_getscn(elf->elf, sec->idx);
@@ -570,13 +571,17 @@ int elf_write(struct elf *elf)
WARN_ELF("elf_getscn");
return -1;
}
- if (!gelf_update_shdr (s, &sec->sh)) {
+ if (!gelf_update_shdr(s, &sec->sh)) {
WARN_ELF("gelf_update_shdr");
return -1;
}
}
}
+ /* Make sure the new section header entries get updated properly. */
+ elf_flagelf(elf->elf, ELF_C_SET, ELF_F_DIRTY);
+
+ /* Write all changes to the file. */
if (elf_update(elf->elf, ELF_C_WRITE) < 0) {
WARN_ELF("elf_update");
return -1;
^ permalink raw reply related [flat|nested] 3+ messages in thread
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