Package: diffutils;
Reported by: Peter Dyballa <Peter_Dyballa <at> Web.DE>
Date: Wed, 16 Apr 2025 10:55:02 UTC
Severity: normal
Message #83 received at 77840 <at> debbugs.gnu.org (full text, mbox):
From: Peter Dyballa <Peter_Dyballa <at> Web.DE> To: Paul Eggert <eggert <at> cs.ucla.edu> Cc: 77840 <at> debbugs.gnu.org Subject: Re: [bug-diffutils] bug#77840: Testing diffutils 3.12 on PPC Mac OS X 10.4.11, Tiger, produces so many failures Date: Mon, 16 Jun 2025 16:39:56 +0200
> Am 13.06.2025 um 00:14 schrieb Paul Eggert <eggert <at> cs.ucla.edu>:
>
> On 2025-06-12 03:29, Peter Dyballa wrote:
>> (gdb) p base
>> $2 = 0x0
>
> That's obviously wrong; 'base' should not be a null pointer. Can you track down why it is a null pointer?
I think I found the actual cause: char const *const *line = &curr.file[0].linbuf[i++];.
This statement on line #376 in context.c is probably too much for GCC 4.2… (To prove that assumption I should compile diffutils 3.12 with GCC 7, GCC 10, or GCC 14.)
Here is again a wide comparison, correct vs. wrong:
x86_64 macOS High Sierra, Version 10.13.6, GNU gdb (GDB) 14.2 | PPC Mac OS X 10.4.11, Tiger, GNU gdb 6.3.50-20050815 (Apple version gdb-696), 2007
––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––
(gdb) on line #369 | (gdb) n
(gdb) on line #374 | (gdb) n
(gdb) on line #376 | (gdb) n
(gdb) p line | (gdb) p line
$13 = (const char * const *) 0x40137c | $1 = (const char * const *) 0x100607098
(gdb) p *line | (gdb) p *line
$14 = 0x0 | $2 = 0x101001630 "compiler.cxx_standard \\\n", ' ' …
(gdb) p **line | (gdb) p **line
Cannot access memory at address 0x0 | $3 = 99 'c'
(gdb) p curr | (gdb) p curr
$15 = { | 'curr' has unknown type; cast it to its declared type
file = {{ |
desc = 7, |
openerr = 0, |
err = 0, |
name = 0xbfffd8e2 "Portfile-graphite2-312", |
filetype = 0x56558 "regular file", |
stat = { |
st_dev = 234881030, |
st_ino = 121849958, |
st_mode = 33188, |
st_nlink = 1, |
st_uid = 501, |
st_gid = 80, |
st_rdev = 0, |
st_atimespec = { |
tv_sec = 1750069349, |
tv_nsec = 0 |
}, |
st_mtimespec = { |
tv_sec = 1749476888, |
tv_nsec = 0 |
}, |
st_ctimespec = { |
tv_sec = 1749650195, |
tv_nsec = 0 |
}, |
st_size = 1412, |
st_blocks = 8, |
st_blksize = 4096, |
st_flags = 0, |
st_gen = 0, |
st_lspare = 0, |
st_qspare = {0, 0} |
}, |
dirstream = 0x0, |
buffer = 0x1801200, |
bufsize = 4096, |
buffered = 1412, |
linbuf = 0x40138c, |
linbuf_base = -3, |
buffered_lines = 7, |
valid_lines = 10, |
alloc_lines = 13, |
prefix_end = 0x1801630 "compiler.cxx_standard … |
prefix_lines = 30, |
suffix_begin = 0x18016c6 "#test.env", ' ' … |
equivs = 0x4015e0, |
undiscarded = 0x401460, |
realindexes = 0x40147c, |
nondiscarded_lines = 6, |
changed = 0x401444, |
missing_newline = false, |
eof = true, |
equiv_max = 8 |
}, { |
desc = 8, |
openerr = 0, |
err = 0, |
name = 0xbfffd8f9 "Portfile-graphite2", |
filetype = 0x56558 "regular file", |
stat = { |
st_dev = 234881030, |
st_ino = 121849957, |
st_mode = 33188, |
st_nlink = 1, |
st_uid = 501, |
st_gid = 80, |
st_rdev = 0, |
st_atimespec = { |
tv_sec = 1750069324, |
tv_nsec = 0 |
}, |
st_mtimespec = { |
tv_sec = 1749476888, |
tv_nsec = 0 |
}, |
st_ctimespec = { |
tv_sec = 1749650195, |
tv_nsec = 0 |
}, |
st_size = 1412, |
st_blocks = 8, |
st_blksize = 4096, |
st_flags = 0, |
st_gen = 0, |
st_lspare = 0, |
st_qspare = {0, 0} |
}, |
dirstream = 0x0, |
buffer = 0x1803600, |
bufsize = 4096, |
buffered = 1412, |
linbuf = 0x40140c, |
linbuf_base = -3, |
buffered_lines = 7, |
valid_lines = 10, |
alloc_lines = 12, |
prefix_end = 0x1803a30 "compiler.cxx_standard … |
prefix_lines = 30, |
suffix_begin = 0x1803ac6 "#test.env", ' ' … |
equivs = 0x401620, |
undiscarded = 0x401498, |
realindexes = 0x4014b4, |
nondiscarded_lines = 6, |
changed = 0x401468, |
missing_newline = false, |
eof = true, |
equiv_max = 8 |
}}, |
parent = 0x59b4c |
} |
(gdb) p suppress_blank_empty | (gdb) p suppress_blank_empty
$16 = false | 'suppress_blank_empty' has unknown type; cast it to its declared type
suppress_blank_empty && **line == '\n' = $17 = 0 |
(gdb) n | (gdb) n
(gdb) n | (gdb) n
(gdb) step | (gdb) step
print_1_line (line_flag=0x0, line=0x40137c) at util.c:989 | print_1_line (line_flag=0x0, line=0x100607098) at util.c:989
(gdb) step | (gdb) step
print_1_line_nl (line_flag=0x0, line=0x40137c, skip_nl=false) … | print_1_line_nl (line_flag=0x0, line=0x100607098, skip_nl=false) at util.c:1001
--
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Pete <]
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