* [PATCH] debugedit: Skip relocations with missing symbol/section offset.
@ 2021-07-01 10:05 Mark Wielaard
2021-07-01 20:12 ` Tom Stellard
0 siblings, 1 reply; 3+ messages in thread
From: Mark Wielaard @ 2021-07-01 10:05 UTC (permalink / raw)
To: debugedit; +Cc: Tom Stellard, Mark Wielaard
We tried to handle relocations that didn't have a symbol associated
with any section. The would cause a message like: "Unhandled
relocation 1 in .debug_info section". Which wasn't that helpful
either. So skip relocations without an associated symbol section index
and improve the error message a little.
* debugedit.c (setup_relbuf): Continue when sym.st_shndx == 0.
Add relocation index to error message.
Signed-off-by: Mark Wielaard <mark@klomp.org>
---
tools/debugedit.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/tools/debugedit.c b/tools/debugedit.c
index c6975b2..d0c6371 100644
--- a/tools/debugedit.c
+++ b/tools/debugedit.c
@@ -561,10 +561,11 @@ setup_relbuf (DSO *dso, debug_section *sec, int *reltype)
continue;
/* Only consider relocations against .debug_str, .debug_line,
.debug_line_str, and .debug_abbrev. */
- if (sym.st_shndx != debug_sections[DEBUG_STR].sec
- && sym.st_shndx != debug_sections[DEBUG_LINE].sec
- && sym.st_shndx != debug_sections[DEBUG_LINE_STR].sec
- && sym.st_shndx != debug_sections[DEBUG_ABBREV].sec)
+ if (sym.st_shndx == 0 ||
+ (sym.st_shndx != debug_sections[DEBUG_STR].sec
+ && sym.st_shndx != debug_sections[DEBUG_LINE].sec
+ && sym.st_shndx != debug_sections[DEBUG_LINE_STR].sec
+ && sym.st_shndx != debug_sections[DEBUG_ABBREV].sec))
continue;
rela.r_addend += sym.st_value;
rtype = ELF64_R_TYPE (rela.r_info);
@@ -625,8 +626,8 @@ setup_relbuf (DSO *dso, debug_section *sec, int *reltype)
#endif
default:
fail:
- error (1, 0, "%s: Unhandled relocation %d in %s section",
- dso->filename, rtype, sec->name);
+ error (1, 0, "%s: Unhandled relocation %d at [%d] for %s section",
+ dso->filename, rtype, ndx, sec->name);
}
relend->ptr = sec->data
+ (rela.r_offset - base);
--
2.32.0
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] debugedit: Skip relocations with missing symbol/section offset.
2021-07-01 10:05 [PATCH] debugedit: Skip relocations with missing symbol/section offset Mark Wielaard
@ 2021-07-01 20:12 ` Tom Stellard
2021-07-05 14:38 ` Mark Wielaard
0 siblings, 1 reply; 3+ messages in thread
From: Tom Stellard @ 2021-07-01 20:12 UTC (permalink / raw)
To: Mark Wielaard, debugedit
On 7/1/21 3:05 AM, Mark Wielaard wrote:
> We tried to handle relocations that didn't have a symbol associated
> with any section. The would cause a message like: "Unhandled
> relocation 1 in .debug_info section". Which wasn't that helpful
> either. So skip relocations without an associated symbol section index
> and improve the error message a little.
>
> * debugedit.c (setup_relbuf): Continue when sym.st_shndx == 0.
> Add relocation index to error message.
>
I tested this and can confirm that it fixes my issue with the
Fedora kernel builds with clang and LTO.
-Tom
> Signed-off-by: Mark Wielaard <mark@klomp.org>
> ---
> tools/debugedit.c | 13 +++++++------
> 1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/tools/debugedit.c b/tools/debugedit.c
> index c6975b2..d0c6371 100644
> --- a/tools/debugedit.c
> +++ b/tools/debugedit.c
> @@ -561,10 +561,11 @@ setup_relbuf (DSO *dso, debug_section *sec, int *reltype)
> continue;
> /* Only consider relocations against .debug_str, .debug_line,
> .debug_line_str, and .debug_abbrev. */
> - if (sym.st_shndx != debug_sections[DEBUG_STR].sec
> - && sym.st_shndx != debug_sections[DEBUG_LINE].sec
> - && sym.st_shndx != debug_sections[DEBUG_LINE_STR].sec
> - && sym.st_shndx != debug_sections[DEBUG_ABBREV].sec)
> + if (sym.st_shndx == 0 ||
> + (sym.st_shndx != debug_sections[DEBUG_STR].sec
> + && sym.st_shndx != debug_sections[DEBUG_LINE].sec
> + && sym.st_shndx != debug_sections[DEBUG_LINE_STR].sec
> + && sym.st_shndx != debug_sections[DEBUG_ABBREV].sec))
> continue;
> rela.r_addend += sym.st_value;
> rtype = ELF64_R_TYPE (rela.r_info);
> @@ -625,8 +626,8 @@ setup_relbuf (DSO *dso, debug_section *sec, int *reltype)
> #endif
> default:
> fail:
> - error (1, 0, "%s: Unhandled relocation %d in %s section",
> - dso->filename, rtype, sec->name);
> + error (1, 0, "%s: Unhandled relocation %d at [%d] for %s section",
> + dso->filename, rtype, ndx, sec->name);
> }
> relend->ptr = sec->data
> + (rela.r_offset - base);
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] debugedit: Skip relocations with missing symbol/section offset.
2021-07-01 20:12 ` Tom Stellard
@ 2021-07-05 14:38 ` Mark Wielaard
0 siblings, 0 replies; 3+ messages in thread
From: Mark Wielaard @ 2021-07-05 14:38 UTC (permalink / raw)
To: Tom Stellard, debugedit
Hi Tom,
On Thu, 2021-07-01 at 13:12 -0700, Tom Stellard wrote:
> On 7/1/21 3:05 AM, Mark Wielaard wrote:
> > We tried to handle relocations that didn't have a symbol associated
> > with any section. The would cause a message like: "Unhandled
> > relocation 1 in .debug_info section". Which wasn't that helpful
> > either. So skip relocations without an associated symbol section
> > index
> > and improve the error message a little.
> >
> > * debugedit.c (setup_relbuf): Continue when sym.st_shndx == 0.
> > Add relocation index to error message.
> >
>
> I tested this and can confirm that it fixes my issue with the
> Fedora kernel builds with clang and LTO.
Thanks for testing, pushed to main.
Note that although debugedit now silently ignores these noop
relocations they do still produce useless/broken DWARF.
Cheers,
Mark
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-07-01 10:05 [PATCH] debugedit: Skip relocations with missing symbol/section offset Mark Wielaard
2021-07-01 20:12 ` Tom Stellard
2021-07-05 14:38 ` Mark Wielaard
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