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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - memory sanitizer reports a false positive? with fts code"
href="http://llvm.org/bugs/show_bug.cgi?id=17267">17267</a>
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<th>Summary</th>
<td>memory sanitizer reports a false positive? with fts code
</td>
</tr>
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<th>Product</th>
<td>compiler-rt
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>compiler-rt
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>ed0.88.prez@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
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<th>Classification</th>
<td>Unclassified
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</tr></table>
<p>
<div>
<pre>Hi. I get this problem when executing this code:
<a href="https://raw.github.com/rheit/zdoom/master/tools/zipdir/zipdir.c">https://raw.github.com/rheit/zdoom/master/tools/zipdir/zipdir.c</a> compiled with
memory sanitizer:
==30138== WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x7fdae305ab93 in add_dirs
/home/edward-san/zdoom/trunk/tools/zipdir/zipdir.c:609
#1 0x7fdae3079227 in main
/home/edward-san/zdoom/trunk/tools/zipdir/zipdir.c:1623
#2 0x7fdae1dbcea4 in __libc_start_main
/build/buildd/eglibc-2.17/csu/libc-start.c:260
#3 0x7fdae3057d7c in _start
(/home/edward-san/zdoom/trunk/debug_san/tools/zipdir/zipdir+0x69d7c)
Uninitialized value was created by a heap allocation
#0 0x7fdae3026a83 in __interceptor_malloc
/home/edward-san/srcllvm/projects/compiler-rt/lib/msan/msan_interceptors.cc:836
#1 0x7fdae1e8a56f in fts_alloc /build/buildd/eglibc-2.17/io/fts.c:990
#2 0x7fdae1e8a56f in fts_open /build/buildd/eglibc-2.17/io/fts.c:143
SUMMARY: MemorySanitizer: use-of-uninitialized-value
/home/edward-san/zdoom/trunk/tools/zipdir/zipdir.c:609 add_dirs
Exiting
I reduced the code to this:
$ cat fts_read_bug.c
#include <fts.h>
int main()
{
char * const argv[] = {"/usr/local/include", 0};
FTS *fts;
FTSENT *ent;
fts = fts_open(argv, FTS_LOGICAL, 0);
if (fts == 0)
return -1;
ent = fts_read(fts);
if (ent != 0 &&
ent->fts_info == FTS_D)
return 1;
fts_close(fts);
return 0;
}
In this case, the message is:
==13273== WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x7f5b6f7899b5 in main /home/edward-san/llvm/fts_read_bug.c:16
#1 0x7f5b6e916ea4 in __libc_start_main
/build/buildd/eglibc-2.17/csu/libc-start.c:260
#2 0x7f5b6f7893fc in _start (/home/edward-san/llvm/a.out+0x683fc)
Uninitialized value was created by a heap allocation
#0 0x7f5b6f758103 in __interceptor_malloc
/home/edward-san/srcllvm/projects/compiler-rt/lib/msan/msan_interceptors.cc:836
#1 0x7f5b6e9e456f in fts_alloc /build/buildd/eglibc-2.17/io/fts.c:990
#2 0x7f5b6e9e456f in fts_open /build/buildd/eglibc-2.17/io/fts.c:143
SUMMARY: MemorySanitizer: use-of-uninitialized-value
/home/edward-san/llvm/fts_read_bug.c:16 main
Exiting
I have no idea of why it happens.</pre>
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