I wrote a C program on linux to process large amount of data, it run OK most of the time. But when processing a set of particular data it always told me the 'segmentation fault' error, I tried to use gdb without luck (see my another question How to deal segmentation fault with GDB under particular circumstance?), so I tried to use valgrind. It didn't tell me the 'segmentation fault' error when run with valgrind. So how to find the bug according to these valgrind output?
==2441== Invalid write of size 4
==2441== at 0x404893: nodes_term32_flush (tyn_indexer.c:227)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1233c080 is 0 bytes after a block of size 1,048,576 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x406BEB: tyn_build_index (tyn_indexer.c:663)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid write of size 4
==2441== at 0x4048D8: nodes_term32_flush (tyn_indexer.c:254)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1233c080 is 0 bytes after a block of size 1,048,576 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x406BEB: tyn_build_index (tyn_indexer.c:663)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid read of size 4
==2441== at 0x40450D: nodes_term32_flush (tyn_indexer.c:260)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1233c080 is 0 bytes after a block of size 1,048,576 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x406BEB: tyn_build_index (tyn_indexer.c:663)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid read of size 4
==2441== at 0x404878: nodes_term32_flush (tyn_indexer.c:224)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1233c080 is 0 bytes after a block of size 1,048,576 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x406BEB: tyn_build_index (tyn_indexer.c:663)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid write of size 4
==2441== at 0x40487F: nodes_term32_flush (tyn_indexer.c:224)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1233c080 is 0 bytes after a block of size 1,048,576 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x406BEB: tyn_build_index (tyn_indexer.c:663)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid read of size 4
==2441== at 0x4048BD: nodes_term32_flush (tyn_indexer.c:251)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1233c094 is not stack'd, malloc'd or (recently) free'd
==2441==
==2441== Invalid write of size 4
==2441== at 0x4048C4: nodes_term32_flush (tyn_indexer.c:251)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1233c094 is not stack'd, malloc'd or (recently) free'd
==2441==
==2441== Invalid read of size 4
==2441== at 0x4093A0: tyn_p4d_encode32 (tyn_coder.c:645)
==2441== by 0x4045F0: nodes_term32_flush (tyn_indexer.c:132)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1233c080 is 0 bytes after a block of size 1,048,576 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x406BEB: tyn_build_index (tyn_indexer.c:663)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid read of size 4
==2441== at 0x409490: tyn_p4d_encode32 (tyn_coder.c:669)
==2441== by 0x4045F0: nodes_term32_flush (tyn_indexer.c:132)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1233c080 is 0 bytes after a block of size 1,048,576 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x406BEB: tyn_build_index (tyn_indexer.c:663)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid read of size 4
==2441== at 0x4094A7: tyn_p4d_encode32 (tyn_coder.c:667)
==2441== by 0x4045F0: nodes_term32_flush (tyn_indexer.c:132)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1233c088 is 8 bytes after a block of size 1,048,576 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x406BEB: tyn_build_index (tyn_indexer.c:663)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid read of size 4
==2441== at 0x409574: tyn_p4d_encode32 (tyn_coder.c:694)
==2441== by 0x4045F0: nodes_term32_flush (tyn_indexer.c:132)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1233c080 is 0 bytes after a block of size 1,048,576 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x406BEB: tyn_build_index (tyn_indexer.c:663)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid read of size 4
==2441== at 0x4095A6: tyn_p4d_encode32 (tyn_coder.c:708)
==2441== by 0x4045F0: nodes_term32_flush (tyn_indexer.c:132)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1233c088 is 8 bytes after a block of size 1,048,576 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x406BEB: tyn_build_index (tyn_indexer.c:663)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid read of size 4
==2441== at 0x409524: tyn_p4d_encode32 (tyn_coder.c:697)
==2441== by 0x4045F0: nodes_term32_flush (tyn_indexer.c:132)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1233c08c is 12 bytes after a block of size 1,048,576 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x406BEB: tyn_build_index (tyn_indexer.c:663)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid read of size 4
==2441== at 0x40953A: tyn_p4d_encode32 (tyn_coder.c:700)
==2441== by 0x4045F0: nodes_term32_flush (tyn_indexer.c:132)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1233c08c is 12 bytes after a block of size 1,048,576 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x406BEB: tyn_build_index (tyn_indexer.c:663)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid read of size 4
==2441== at 0x409552: tyn_p4d_encode32 (tyn_coder.c:702)
==2441== by 0x4045F0: nodes_term32_flush (tyn_indexer.c:132)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1243c2fc is 12 bytes after a block of size 16 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x40785B: tyn_exsorter_sort (tyn_exsorter.c:106)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid read of size 4
==2441== at 0x407CB7: tyn_iS16_encode32 (tyn_coder.c:96)
==2441== by 0x409621: tyn_p4d_encode32 (tyn_coder.c:725)
==2441== by 0x4045F0: nodes_term32_flush (tyn_indexer.c:132)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1243d880 is 0 bytes after a block of size 16 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x40785B: tyn_exsorter_sort (tyn_exsorter.c:106)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid read of size 4
==2441== at 0x407D20: tyn_iS16_encode32 (tyn_coder.c:109)
==2441== by 0x409621: tyn_p4d_encode32 (tyn_coder.c:725)
==2441== by 0x4045F0: nodes_term32_flush (tyn_indexer.c:132)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1243d880 is 0 bytes after a block of size 16 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x40785B: tyn_exsorter_sort (tyn_exsorter.c:106)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Invalid read of size 4
==2441== at 0x407D37: tyn_iS16_encode32 (tyn_coder.c:108)
==2441== by 0x409621: tyn_p4d_encode32 (tyn_coder.c:725)
==2441== by 0x4045F0: nodes_term32_flush (tyn_indexer.c:132)
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441== Address 0x1243d8a8 is not stack'd, malloc'd or (recently) free'd
==2441==
==2441== Use of uninitialised value of size 8
==2441== at 0x3AE9C4726B: _itoa_word (in /lib64/libc-2.14.90.so)
==2441== by 0x3AE9C49852: vfprintf (in /lib64/libc-2.14.90.so)
==2441== by 0x3AE9C51FE8: printf (in /lib64/libc-2.14.90.so)
==2441== by 0x4071EF: tyn_build_index (tyn_indexer.c:888)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Conditional jump or move depends on uninitialised value(s)
==2441== at 0x3AE9C47275: _itoa_word (in /lib64/libc-2.14.90.so)
==2441== by 0x3AE9C49852: vfprintf (in /lib64/libc-2.14.90.so)
==2441== by 0x3AE9C51FE8: printf (in /lib64/libc-2.14.90.so)
==2441== by 0x4071EF: tyn_build_index (tyn_indexer.c:888)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
document id: 0
==2441== Conditional jump or move depends on uninitialised value(s)
==2441== at 0x3AE9C4774E: vfprintf (in /lib64/libc-2.14.90.so)
==2441== by 0x3AE9C51FE8: printf (in /lib64/libc-2.14.90.so)
==2441== by 0x4073AD: tyn_build_index (tyn_indexer.c:900)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Use of uninitialised value of size 8
==2441== at 0x3AE9C4726B: _itoa_word (in /lib64/libc-2.14.90.so)
==2441== by 0x3AE9C49852: vfprintf (in /lib64/libc-2.14.90.so)
==2441== by 0x3AE9C51FE8: printf (in /lib64/libc-2.14.90.so)
==2441== by 0x4073AD: tyn_build_index (tyn_indexer.c:900)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
==2441== Conditional jump or move depends on uninitialised value(s)
==2441== at 0x3AE9C47275: _itoa_word (in /lib64/libc-2.14.90.so)
==2441== by 0x3AE9C49852: vfprintf (in /lib64/libc-2.14.90.so)
==2441== by 0x3AE9C51FE8: printf (in /lib64/libc-2.14.90.so)
==2441== by 0x4073AD: tyn_build_index (tyn_indexer.c:900)
==2441== by 0x40384F: main (tyn_indexer.c:943)
==2441==
int32_t category: 0
bytes_collected: 972467429
196220 bytes/s
tyn_config->indexer->dl_directory: /dragon/tyan
tyn_config->indexer->memory_limit: 10240000
==2441==
==2441== HEAP SUMMARY:
==2441== in use at exit: 214,695,668 bytes in 399,272 blocks
==2441== total heap usage: 401,095 allocs, 1,823 frees, 219,225,806 bytes allocated
==2441==
==2441== LEAK SUMMARY:
==2441== definitely lost: 9,442,580 bytes in 27 blocks
==2441== indirectly lost: 34,682,771 bytes in 81 blocks
==2441== possibly lost: 170,557,809 bytes in 399,140 blocks
==2441== still reachable: 12,508 bytes in 24 blocks
==2441== suppressed: 0 bytes in 0 blocks
==2441== Rerun with --leak-check=full to see details of leaked memory
==2441==
==2441== For counts of detected and suppressed errors, rerun with: -v
==2441== Use --track-origins=yes to see where uninitialised values come from
==2441== ERROR SUMMARY: 32680 errors from 23 contexts (suppressed: 2 from 2)
That's a lot of output you have here. You should have condensed it more to the areas you are interested. I'll try to give a few general pointers, though.
==2441== Invalid write of size 4
opens a "block" that tells you details about the allocated memory and the stack backtrace of its allocation and the error site. The ==2441==
is the PID of the process, which is useful in cases where multiple processes run in parallel.
Error site (comments added with #
). The stack backtrace is always in reverse order, meaning the crash (or what would have become a crash normally) site is at the top of the listing and the calls that led there are listed in reverse order below:
# This points to a function nodes_term32_flush() in file tyn_indexer.c on line 227
==2441== at 0x404893: nodes_term32_flush (tyn_indexer.c:227)
# the format is the same, at this line tyn_exsorter_sort() calls nodes_term32_flush()
==2441== by 0x407B77: tyn_exsorter_sort (tyn_exsorter.c:131)
# ... and so on
==2441== by 0x406DDE: tyn_build_index (tyn_indexer.c:731)
# ... leading up to the process "entry point"
==2441== by 0x40384F: main (tyn_indexer.c:943)
The memory block that was affected. The first line tells us that a block of exactly one MiB was allocated and that (together with the output above) you were reading the first 4 bytes (likely a 32bit value) after the last allocated byte of that block. The rest of the format follows what you know from the stack backtrace above.
==2441== Address 0x1233c080 is 0 bytes after a block of size 1,048,576 alloc'd
==2441== at 0x4A074CD: malloc (vg_replace_malloc.c:236)
==2441== by 0x406BEB: tyn_build_index (tyn_indexer.c:663)
==2441== by 0x40384F: main (tyn_indexer.c:943)
All the repetitions afterwards are - from experience - most often a consequence of the first error. So always start fixing the first listed issue in a sequence of reported issues.
Now for the other error class that appears in your output:
==2441== Use of uninitialised value of size 8
# All library functions here ...
==2441== at 0x3AE9C4726B: _itoa_word (in /lib64/libc-2.14.90.so)
==2441== by 0x3AE9C49852: vfprintf (in /lib64/libc-2.14.90.so)
==2441== by 0x3AE9C51FE8: printf (in /lib64/libc-2.14.90.so)
# ... but this one should be yours. Check out this file/line to see what can be the problem with the printf() call
==2441== by 0x4071EF: tyn_build_index (tyn_indexer.c:888)
==2441== by 0x40384F: main (tyn_indexer.c:943)
The following is likely again just a consequence of the output above:
==2441== Conditional jump or move depends on uninitialised value(s)
==2441== at 0x3AE9C47275: _itoa_word (in /lib64/libc-2.14.90.so)
==2441== by 0x3AE9C49852: vfprintf (in /lib64/libc-2.14.90.so)
==2441== by 0x3AE9C51FE8: printf (in /lib64/libc-2.14.90.so)
==2441== by 0x4071EF: tyn_build_index (tyn_indexer.c:888)
==2441== by 0x40384F: main (tyn_indexer.c:943)
I strongly suggest two things: read the Valgrind manual (I know this sounds patronizing, but it's worth it) and make use of its many options. I created a few functions that I am using on my development machines:
# vim: set autoindent smartindent tabstop=2 shiftwidth=2 expandtab filetype=sh:
function vgrun
{
local COMMAND="$1"
local NAME="$2"
[[ -n "$COMMAND" ]] || { echo "Syntax: vgrun <command> <name>"; return; }
[[ -n "$NAME" ]] || { echo "Syntax vgrun <command> <name>"; return; }
valgrind \
--leak-check=full --error-limit=no --track-origins=yes \
--undef-value-errors=yes --log-file=valgrind-${NAME}.log \
--read-var-info=yes \
$COMMAND | tee valgrind-${NAME}-output.log 2>&1
}
function vgtrace
{
local COMMAND="$1"
local NAME="$2"
[[ -n "$COMMAND" ]] || { echo "Syntax: vgtrace <command> <name>"; return; }
[[ -n "$NAME" ]] || { echo "Syntax vgtrace <command> <name>"; return; }
valgrind \
--leak-check=full --error-limit=no --track-origins=yes \
--undef-value-errors=yes --log-file=valgrind-${NAME}.log \
--read-var-info=yes --trace-children=yes \
$COMMAND | tee valgrind-${NAME}-output.log 2>&1
}
function vgdbg
{
[[ -n "$*" ]] || { echo "Syntax: vgrun <command>"; return; }
valgrind \
--leak-check=full --error-limit=no --track-origins=yes \
--undef-value-errors=yes --read-var-info=yes --db-attach=yes \
"$@"
}
vgrun
simply runs a command with Valgrind. Note that the command needs to be in quotes with all its parameters for this one to work. vgtrace
is merely a variation of vgrun
, adding --trace-children=yes
to the Valgrind command line. The most useful, by far, is vgdbg
, which will ask you to attach GDB to the running program and thus lets you interactively debug the issue at hand, including properly inspecting stack frames, values etc - if you speak GDB, that is.
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