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Binutils 2.29.1 breaks libpcap on sparc32 by filling .got

Rolf Eike Beer eb@emlix.com
Thu Dec 7 13:58:00 GMT 2017 
I have a T5120 running Gentoo Linux (64 bit kernel, 32 bit userspace). When 
switching between binutils 2.28.1 and 2.29.1 I can break/unbreak libpcap. The 
broken version can easily be detected: tcpdump crashes on start. When I 
compare the 2 libraries using diffoscope this is the diff (truncated):

--- libpcap-good
+++ libpcap-bad
├── readelf --wide --decompress --hex-dump=.got {}
│ @@ -1,161 +1,161 @@
│  
│  Hex dump of section '.got':
│ -  0x0004a000 00049f18 00000000 00000000 00000000 ................
│ -  0x0004a010 00000000 00000000 00000000 00000000 ................
│ -  0x0004a020 00000000 00000000 00000000 00000000 ................
│ -  0x0004a030 00000000 00000000 00000000 00000000 ................
│ -  0x0004a040 00000000 00000000 00000000 00000000 ................
│ +  0x0004a000 00049f18 000054c0 000054e0 00005500 ......T...T...U.
│ +  0x0004a010 00005520 000058e0 00005b00 000270a0 ..U ..X...[...p.
│ +  0x0004a020 0004afa4 00006860 00006880 000069a0 ......h`..h...i.
│ +  0x0004a030 00006ca0 00006fc0 00007180 00007300 ..l...o...q...s.
│ +  0x0004a040 000075a0 000076c0 000080a0 000270b0 ..u...v.......p.

This section is the only difference.  I have tried adding 
0fb7012e88683b8bd67a4fb8f782359fa0e11724, 
00956d3a8ab1b56fcdf63aee4ed5c5a1d46a7a48, and 
f6a36b0c9e537e4525f3b0687a4f76b4f77bf173 to the build, or reverting 
5b86074c4a84e32ca55a6c72c5fca45d97dc9374, neither made a difference. The 
results above are done including the Gentoo patchset, but I verified that the 
vanilla version breaks the same way, it just has more changes.

I have build many other things with these binutils and have not observed a 
breakage elsewhere, but this one is very stable and can be reproduced every 
time.

Any hints?

Eike
-- 
Rolf Eike Beer, emlix GmbH, http://www.emlix.com
Fon +49 551 30664-0, Fax +49 551 30664-11
Bertha-von-Suttner-Str. 9, 37085 Göttingen, Germany
Sitz der Gesellschaft: Göttingen, Amtsgericht Göttingen HR B 3160
Geschäftsführung: Heike Jordan, Dr. Uwe Kracke – Ust-IdNr.: DE 205 198 055

emlix – smart embedded open source
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