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FS#4222 - valgrind: does not detect memory leaks depite unstripped libraries #9203

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openwrt-bot opened this issue Jan 9, 2022 · 1 comment
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@openwrt-bot
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MikePetullo:

I am using valgrind 3.18.1-1 on x86_64 r18400-f9782f5bcd. This build uses musl 1.2.2-3. My libraries, to include libc, are not stripped.

According to the upstream bug at https://bugs.kde.org/show_bug.cgi?id=435441, changes to musl left valgrind unable to detect memory leaks. The workaround proposed in that bug report, namely passing "--soname-synonyms=somalloc=NONE" to valgrind, seems to fix the problem on OpenWrt.

Here is an example program:

#include #include

int f(void) {
char *buf = malloc(BUFSIZ);
if (buf == NULL) {
return -1;
}
return 0;
}

int main(void)
{
f();
}

I compiled this with "gcc -O0 -o test test.c", and I ran the following to demonstrate the problem and workaround:

$ valgrind --leak-check=full ./test
==31728== Memcheck, a memory error detector
==31728== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==31728== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==31728== Command: ./test
==31728==
==31728==
==31728== HEAP SUMMARY:
==31728== in use at exit: 0 bytes in 0 blocks
==31728== total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==31728==
==31728== All heap blocks were freed -- no leaks are possible
==31728==
==31728== For lists of detected and suppressed errors, rerun with: -s
==31728== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
$ valgrind --leak-check=full --soname-synonyms=somalloc=NONE ./test
==31732== Memcheck, a memory error detector
==31732== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==31732== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==31732== Command: ./test
==31732==
==31732==
==31732== HEAP SUMMARY:
==31732== in use at exit: 1,024 bytes in 1 blocks
==31732== total heap usage: 1 allocs, 0 frees, 1,024 bytes allocated
==31732==
==31732== 1,024 bytes in 1 blocks are definitely lost in loss record 1 of 1
==31732== at 0x48806B6: malloc (vg_replace_malloc.c:381)
==31732== by 0x40111B: f (in /home/mike@flyn.org/valgrindC/test)
==31732== by 0x40113D: main (in /home/mike@flyn.org/valgrindC/test)
==31732==
==31732== LEAK SUMMARY:
==31732== definitely lost: 1,024 bytes in 1 blocks
==31732== indirectly lost: 0 bytes in 0 blocks
==31732== possibly lost: 0 bytes in 0 blocks
==31732== still reachable: 0 bytes in 0 blocks
==31732== suppressed: 0 bytes in 0 blocks
==31732==
==31732== For lists of detected and suppressed errors, rerun with: -s
==31732== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

@openwrt-bot
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jow-:

Shouldn't that be reported to musl libc then? What are we supposed to do about this?

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