Package: emacs;
Reported by: Petr Hracek <phracek <at> redhat.com>
Date: Wed, 20 May 2015 07:59:01 UTC
Severity: important
Tags: patch
Done: Lars Ingebrigtsen <larsi <at> gnus.org>
Bug is archived. No further changes may be made.
Message #186 received at 20614 <at> debbugs.gnu.org (full text, mbox):
From: Petr Hracek <phracek <at> redhat.com> To: Andreas Schwab <schwab <at> suse.de>, YAMAMOTO Mitsuharu <mituharu <at> math.s.chiba-u.ac.jp> Cc: Jaromir Capik <jcapik <at> redhat.com>, 20614 <at> debbugs.gnu.org, Eli Zaretskii <eliz <at> gnu.org> Subject: Re: bug#20614: Segmentation fault when building on Power8 Little Endian Date: Tue, 13 Oct 2015 09:30:14 +0200
On 10/10/2015 05:44 PM, Andreas Schwab wrote:
> Please try this patch instead:
>
> diff --git a/src/unexelf.c b/src/unexelf.c
> index 483da6e..2e8b4c7 100644
> --- a/src/unexelf.c
> +++ b/src/unexelf.c
> @@ -616,6 +616,32 @@ find_section (const char *name, const char *section_names, const char *file_name
> return -1;
> }
>
> +/* Find the index of the first bss (NOBITS) section, count the number
> + of bss sections that follow and compute the overall size of these
> + sections. */
> +static int
> +find_bss_sections (const char *file_name,
> + ElfW(Ehdr) *old_file_h, ElfW(Shdr) *old_section_h,
> + ElfW (Word) *size, int *num)
> +{
> + ptrdiff_t idx;
> +
> + for (idx = 1; idx < old_file_h->e_shnum; idx++)
> + if (OLD_SECTION_H (idx).sh_type == SHT_NOBITS)
> + {
> + ptrdiff_t idx2 = idx;
> +
> + while (OLD_SECTION_H (idx2 + 1).sh_type == SHT_NOBITS)
> + idx2++;
> + *size = (OLD_SECTION_H (idx2).sh_addr + OLD_SECTION_H (idx2).sh_size
> + - OLD_SECTION_H (idx).sh_addr);
> + *num = idx2 + 1 - idx;
> + return idx;
> + }
> + fatal ("Can't find bss section in %s", file_name);
> + return -1;
> +}
> +
> /* ****************************************************************
> * unexec
> *
> @@ -652,13 +678,14 @@ unexec (const char *new_name, const char *old_name)
>
> ElfW (Addr) old_bss_addr, new_bss_addr;
> ElfW (Word) old_bss_size, new_data2_size;
> + int n_bss_sections;
> ElfW (Off) new_data2_offset;
> ElfW (Addr) new_data2_addr;
> ElfW (Off) old_bss_offset;
> ElfW (Word) new_data2_incr;
>
> ptrdiff_t n, nn;
> - ptrdiff_t old_bss_index, old_sbss_index, old_plt_index;
> + ptrdiff_t old_bss_index;
> ptrdiff_t old_data_index, new_data2_index;
> #if defined _SYSTYPE_SYSV || defined __sgi
> ptrdiff_t old_mdebug_index;
> @@ -716,50 +743,12 @@ unexec (const char *new_name, const char *old_name)
> /* Find the old .bss section. Figure out parameters of the new
> data2 and bss sections. */
>
> - old_bss_index = find_section (".bss", old_section_names,
> - old_name, old_file_h, old_section_h, 0);
> -
> - old_sbss_index = find_section (".sbss", old_section_names,
> - old_name, old_file_h, old_section_h, 1);
> - if (old_sbss_index != -1)
> - if (OLD_SECTION_H (old_sbss_index).sh_type != SHT_NOBITS)
> - old_sbss_index = -1;
> -
> - /* PowerPC64 has .plt in the BSS section. */
> - old_plt_index = find_section (".plt", old_section_names,
> - old_name, old_file_h, old_section_h, 1);
> - if (old_plt_index != -1)
> - if (OLD_SECTION_H (old_plt_index).sh_type != SHT_NOBITS)
> - old_plt_index = -1;
> + old_bss_index = find_bss_sections (old_name, old_file_h, old_section_h,
> + &old_bss_size, &n_bss_sections);
>
> - if (old_sbss_index == -1 && old_plt_index == -1)
> - {
> - old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
> - old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
> - old_bss_offset = OLD_SECTION_H (old_bss_index).sh_offset;
> - new_data2_index = old_bss_index;
> - }
> - else if (old_plt_index != -1
> - && (old_sbss_index == -1
> - || (OLD_SECTION_H (old_sbss_index).sh_addr
> - > OLD_SECTION_H (old_plt_index).sh_addr)))
> - {
> - old_bss_addr = OLD_SECTION_H (old_plt_index).sh_addr;
> - old_bss_size = OLD_SECTION_H (old_bss_index).sh_size
> - + OLD_SECTION_H (old_plt_index).sh_size;
> - if (old_sbss_index != -1)
> - old_bss_size += OLD_SECTION_H (old_sbss_index).sh_size;
> - old_bss_offset = OLD_SECTION_H (old_plt_index).sh_offset;
> - new_data2_index = old_plt_index;
> - }
> - else
> - {
> - old_bss_addr = OLD_SECTION_H (old_sbss_index).sh_addr;
> - old_bss_size = OLD_SECTION_H (old_bss_index).sh_size
> - + OLD_SECTION_H (old_sbss_index).sh_size;
> - old_bss_offset = OLD_SECTION_H (old_sbss_index).sh_offset;
> - new_data2_index = old_sbss_index;
> - }
> + old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
> + old_bss_offset = OLD_SECTION_H (old_bss_index).sh_offset;
> + new_data2_index = old_bss_index;
>
> /* Find the old .data section. Figure out parameters of
> the new data2 and bss sections. */
> @@ -851,20 +840,11 @@ unexec (const char *new_name, const char *old_name)
> {
> /* Compute maximum of all requirements for alignment of section. */
> ElfW (Word) alignment = (NEW_PROGRAM_H (n)).p_align;
> - if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
> + if (OLD_SECTION_H (old_bss_index).sh_addralign > alignment)
> alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
>
> -#ifdef __sgi
> - /* According to r02kar <at> x4u2.desy.de (Karsten Kuenne)
> - and oliva <at> gnu.org (Alexandre Oliva), on IRIX 5.2, we
> - always get "Program segment above .bss" when dumping
> - when the executable doesn't have an sbss section. */
> - if (old_sbss_index != -1)
> -#endif /* __sgi */
> if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz
> - > (old_sbss_index == -1
> - ? old_bss_addr
> - : round_up (old_bss_addr, alignment)))
> + > round_up (old_bss_addr, alignment))
> fatal ("Program segment above .bss in %s", old_name);
>
> if (NEW_PROGRAM_H (n).p_type == PT_LOAD
> @@ -932,12 +912,10 @@ unexec (const char *new_name, const char *old_name)
> memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
> old_file_h->e_shentsize);
>
> - if (n == old_bss_index
> - /* The new bss and sbss section's size is zero, and its file offset
> - and virtual address should be off by NEW_DATA2_SIZE. */
> - || n == old_sbss_index || n == old_plt_index
> - )
> + if (n >= old_bss_index && n < old_bss_index + n_bss_sections)
> {
> + /* The new bss section's size is zero, and its file offset
> + and virtual address should be off by NEW_DATA2_SIZE. */
> /* NN should be `old_s?bss_index + 1' at this point. */
> NEW_SECTION_H (nn).sh_offset = new_data2_offset + new_data2_size;
> NEW_SECTION_H (nn).sh_addr = new_data2_addr + new_data2_size;
> @@ -998,15 +976,6 @@ temacs:
> && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM)
> PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
>
> - if (old_sbss_index != -1)
> - if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".sbss"))
> - {
> - NEW_SECTION_H (nn).sh_offset =
> - round_up (NEW_SECTION_H (nn).sh_offset,
> - NEW_SECTION_H (nn).sh_addralign);
> - NEW_SECTION_H (nn).sh_type = SHT_PROGBITS;
> - }
> -
> /* Now, start to copy the content of sections. */
> if (NEW_SECTION_H (nn).sh_type == SHT_NULL
> || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
> @@ -1226,7 +1195,7 @@ temacs:
> nn = symp->st_shndx;
> if (nn > old_bss_index)
> nn--;
> - if (nn == old_bss_index)
> + if (nn >= old_bss_index && nn < old_bss_index + n_bss_sections)
> memset (new, 0, symp->st_size);
> else
> {
Well, with this patch emacs failed again with message like:
Dumping under the name emacs
emacs: Program segment above .bss in
/home/phracek/rpmbuild/BUILD/emacs-24.3/src/temacs
make[2]: *** [bootstrap-emacs] Error 1
make[2]: Leaving directory `/home/phracek/rpmbuild/BUILD/emacs-24.3/src'
make[1]: *** [src] Error 2
Well:
Header seems to be fine:
ELF Header:
Magic: 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
Class: ELF64
Data: 2's complement, little endian
Ident Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: PowerPC 64-bit
Version: 1 (current)
Entry point address: 0x100184f0
Start of program headers: 64 (bytes into file)
Start of section headers: 14281064 (bytes into file)
Flags: 0x2
Size of this header: 64 (bytes)
Size of program header entries: 56 (bytes)
Number of program headers entries: 9
Size of section header entries: 64 (bytes)
Number of section headers entries: 34
Section header string table index: 31
Section Headers:
[Nr] Name Type Addr Off Size ES
Flags Lk Inf Al
[ 0] NULL 0000000000000000 00000000
00000000 0 0 0 0
[ 1] .interp PROGBITS 0000000010000238 00000238
00000011 0 A 0 0 1
[ 2] .note.ABI-tag NOTE 000000001000024c 0000024c
00000020 0 A 0 0 4
[ 3] .note.gnu.build-id NOTE 000000001000026c 0000026c
00000024 0 A 0 0 4
[ 4] .gnu.hash GNU_HASH 0000000010000290 00000290
000000dc 0 A 5 0 8
[ 5] .dynsym DYNSYM 0000000010000370 00000370
000063f0 24 A 6 1 8
[ 6] .dynstr STRTAB 0000000010006760 00006760
00004ae9 0 A 0 0 1
[ 7] .gnu.version GNU_versym 000000001000b24a 0000b24a
00000854 2 A 5 0 2
[ 8] .gnu.version_r GNU_verneed 000000001000baa0 0000baa0
00000160 0 A 6 10 8
[ 9] .rela.toc RELA 000000001000bc00 0000bc00
00000330 24 A 5 0 8
[10] .rela.plt RELA 000000001000bf30 0000bf30
000060d8 24 A 5 20 8
[11] .init PROGBITS 0000000010012020 00012020
0000004c 0 AX 0 0 32
[12] .text PROGBITS 0000000010012080 00012080
00236f60 0 AX 0 0 32
[13] .fini PROGBITS 0000000010248fe0 00248fe0
00000024 0 AX 0 0 4
[14] .rodata PROGBITS 0000000010249008 00249008
0001fde0 0 A 0 0 8
[15] .eh_frame_hdr PROGBITS 0000000010268de8 00268de8
000073c4 0 A 0 0 4
[16] .eh_frame PROGBITS 00000000102701b0 002701b0
0002e2d8 0 A 0 0 8
[17] .data.rel.ro PROGBITS 00000000102af640 0029f640
00000430 0 WA 0 0 8
[18] .dynamic DYNAMIC 00000000102afa70 0029fa70
00000440 16 WA 6 0 8
[19] .got PROGBITS 00000000102afeb0 0029feb0
00000150 8 WA 0 0 8
[20] .plt NOBITS 00000000102b0000 002a0000
00002058 8 WA 0 0 8
[21] .data PROGBITS 00000000102b2058 002a2058
002c6d36 0 WA 0 0 8
[22] .bss NOBITS 0000000010578d90 00568d8e
00087740 0 WA 0 0 16
[23] .comment PROGBITS 0000000000000000 00568d8e
00000058 1 MS 0 0 1
[24] .debug_aranges PROGBITS 0000000000000000 00568de6
00001350 0 0 0 1
[25] .debug_info PROGBITS 0000000000000000 0056a136
003aea05 0 0 0 1
[26] .debug_abbrev PROGBITS 0000000000000000 00918b3b
00021af4 0 0 0 1
[27] .debug_line PROGBITS 0000000000000000 0093a62f
0007c2d9 0 0 0 1
[28] .debug_str PROGBITS 0000000000000000 009b6908
00047fb3 1 MS 0 0 1
[29] .debug_loc PROGBITS 0000000000000000 009fe8bb
00327db2 0 0 0 1
[30] .debug_ranges PROGBITS 0000000000000000 00d2666d
000781b0 0 0 0 1
[31] .shstrtab STRTAB 0000000000000000 00d9e81d
00000148 0 0 0 1
[32] .symtab SYMTAB 0000000000000000 00d9f1e8
00037ba8 24 33 5414 8
[33] .strtab STRTAB 0000000000000000 00dd6d90
0002e227 0 0 0 1
What debug information do you need?
--
Petr Hracek
Software Engineer
Developer Experience
Red Hat, Inc
Mob: +420777056169
email: phracek <at> redhat.com
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