Re: [tip:x86/urgent] x86/vdso: Discard the __bug_table section

From: H. Peter Anvin
Date: Tue Jun 24 2014 - 14:26:42 EST


On 06/24/2014 11:19 AM, Andy Lutomirski wrote:
>>>
>>> One of the recent x86/urgent vdso commits causes this build failure:
>>>
>>> Error: too many copied sections (max = 13)
>>
>> I can't reproduce this with your config, which suggestes a binutils
>> issue, which is annoying. Can you tell me what version of ld you're
>> using and send me the output of:
>>
>> for i in arch/x86/vdso/*.so.dbg; do echo $i; eu-readelf -S $i; done
>
> Ping!
>
> The current state of this is obviously not so good, but I don't know
> how to proceed.
>

We used to have this kind of problems with PHDRs, where ld would guess
how much space it would need, somehow guess wrong, and fall on its face.

I think we want to actually print the number that we are trying to copy
in addition to the maximum, and I also noticed the test looks wrong.
Thus I would like to propose the following patch as a diagnostic:

diff --git a/arch/x86/vdso/vdso2c.h b/arch/x86/vdso/vdso2c.h
index f42e2ddc663d..94158e100f26 100644
--- a/arch/x86/vdso/vdso2c.h
+++ b/arch/x86/vdso/vdso2c.h
@@ -99,8 +99,9 @@ static void BITSFUNC(copy_section)(struct
BITSFUNC(fake_sections) *out,
if (!copy)
return;

- if (out->count >= out->max_count)
- fail("too many copied sections (max = %d)\n",
out->max_count);
+ if (out->count > out->max_count)
+ fail("too many copied sections (max = %d, need = %d)\n",
+ out->max_count, out->count);

if (in_idx == out->in_shstrndx)
out->out_shstrndx = out->count;

Does anyone have any objection? Andy, I presume I am correct that =>
should be > there?

-hpa
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/