On 09/02/2017 20:14, James Clarke wrote: >> On 9 Feb 2017, at 21:31, Adhemerval Zanella <adhemerval.zane...@linaro.org> >> wrote: >> >> Hi all, >> >> While testing glibc on the kindly provided T5 machine from Debian >> environment, >> I started to see some strange issues on sparc64 where glibc is failing on >> mostly static tests. >> >> Funny thing is I checked the latest working revision I used to update 2.25 >> release page [1] and now the tests that used to pass are now failing. In >> fact I checked even the 2.23 and 2.24 glibc releases and both show the same >> issues as master branch, so I am almost ruling out a glibc regression (which >> was my first idea). >> >> I noted that the machine kernel was updated (from 4.9.2-2 to 4.9.6-3), but >> I am not sure if this is something to kernel. I haven't recorded the >> gcc revision I used on my initial testings. The static tets are failing due >> a memcpy call that issues bogus instructions: >> >> (gdb) r >> Starting program: /home/azanella/glibc/glibc-git-build/elf/tst-tls1-static >> >> Program received signal SIGSEGV, Segmentation fault. >> 0x0000000000000340 in ?? () >> (gdb) bt >> #0 0x0000000000000340 in ?? () >> #1 0x0000000000101fd8 in __libc_setup_tls () at libc-tls.c:180 >> #2 0x0000000000101950 in __libc_start_main (main=0x4e8, argc=<optimized >> out>, argv=0x7feffffef78, init=0x4a8, fini=0x220, rtld_fini=0x0, >> stack_end=0x1) >> at libc-start.c:189 >> #3 0x0000000000100704 in _start () at ../sysdeps/sparc/sparc64/start.S:88 >> Backtrace stopped: previous frame identical to this frame (corrupt stack?) >> >> (gdb) up >> [...] >> 0x0000000000101fc8 <+344>: add %l4, %o0, %o0 >> 0x0000000000101fcc <+348>: mov %i1, %o1 >> 0x0000000000101fd0 <+352>: call 0x2949c0 >> 0x0000000000101fd4 <+356>: stx %o0, [ %i4 + 0x20 ] >> => 0x0000000000101fd8 <+360>: sethi %hi(0x4800), %g3 >> >> It seems 0x2949c0 is a unknown address, where it should be the memcpy one. > > Do you have the .o still for this? I would be interested to see what the > relocation was. One thing that has changed within the last week is enabling > PIE by default in GCC, though this call is a plain PC-relative one. > > Regards, > James >
Yes, objdump shows: $ objdump -r string/memcpy.o string/memcpy.o: file format elf64-sparc RELOCATION RECORDS FOR [.text]: OFFSET TYPE VALUE 0000000000000010 R_SPARC_GOT22 __memcpy_niagara4 0000000000000014 R_SPARC_GOT10 __memcpy_niagara4 0000000000000028 R_SPARC_GOT22 __memcpy_niagara2 000000000000002c R_SPARC_GOT10 __memcpy_niagara2 0000000000000040 R_SPARC_GOT22 __memcpy_niagara1 0000000000000044 R_SPARC_GOT10 __memcpy_niagara1 0000000000000058 R_SPARC_GOT22 __memcpy_ultra3 000000000000005c R_SPARC_GOT10 __memcpy_ultra3 0000000000000068 R_SPARC_GOT22 __memcpy_ultra1 000000000000006c R_SPARC_GOT10 __memcpy_ultra1 0000000000000088 R_SPARC_GOT22 __mempcpy_niagara4 000000000000008c R_SPARC_GOT10 __mempcpy_niagara4 00000000000000a0 R_SPARC_GOT22 __mempcpy_niagara2 00000000000000a4 R_SPARC_GOT10 __mempcpy_niagara2 00000000000000b8 R_SPARC_GOT22 __mempcpy_niagara1 00000000000000bc R_SPARC_GOT10 __mempcpy_niagara1 00000000000000d0 R_SPARC_GOT22 __mempcpy_ultra3 00000000000000d4 R_SPARC_GOT10 __mempcpy_ultra3 00000000000000e0 R_SPARC_GOT22 __mempcpy_ultra1 00000000000000e4 R_SPARC_GOT10 __mempcpy_ultra1 [debug relocations...] Which is expected to use GOT relocations for PIE. And if I build the same object with -fno-pie I do see: string/memcpy.o: file format elf64-sparc RELOCATION RECORDS FOR [.text]: OFFSET TYPE VALUE 0000000000000010 R_SPARC_HI22 __memcpy_niagara4 0000000000000014 R_SPARC_LO10 __memcpy_niagara4 0000000000000028 R_SPARC_HI22 __memcpy_niagara2 000000000000002c R_SPARC_LO10 __memcpy_niagara2 0000000000000040 R_SPARC_HI22 __memcpy_niagara1 0000000000000044 R_SPARC_LO10 __memcpy_niagara1 0000000000000058 R_SPARC_HI22 __memcpy_ultra3 000000000000005c R_SPARC_LO10 __memcpy_ultra3 0000000000000068 R_SPARC_HI22 __memcpy_ultra1 000000000000006c R_SPARC_LO10 __memcpy_ultra1 0000000000000088 R_SPARC_HI22 __mempcpy_niagara4 000000000000008c R_SPARC_LO10 __mempcpy_niagara4 00000000000000a0 R_SPARC_HI22 __mempcpy_niagara2 00000000000000a4 R_SPARC_LO10 __mempcpy_niagara2 00000000000000b8 R_SPARC_HI22 __mempcpy_niagara1 00000000000000bc R_SPARC_LO10 __mempcpy_niagara1 00000000000000d0 R_SPARC_HI22 __mempcpy_ultra3 00000000000000d4 R_SPARC_LO10 __mempcpy_ultra3 00000000000000e0 R_SPARC_HI22 __mempcpy_ultra1 00000000000000e4 R_SPARC_LO10 __mempcpy_ultra1 I think no one rally tried to build the glibc with a default pie gcc so it might the side-effects of it. I tried to build with CC='gcc -fno-pie', but it failed on sunrpc/cross-rpcgen again with a segfault due a bogus jump from a possible mis-relocation. Rebuilding using a gcc 6 built without --enable-default-pie I saw not more issues in glibc testcases.