https://bugs.kde.org/show_bug.cgi?id=464671
--- Comment #8 from Romain Geissler <romain.geiss...@amadeus.com> ---
(In reply to Mark Wielaard from comment #7)
> Is this just for strcmp in ld.so?
> In that case the intercept in shared/vg_replace_strmem.c should in theory
> fix that.
Hi,
Yes in my case it happens only for strcmp in ld.so, I tried again just now with
an unpatched toolchain on our side, using a unittest binary that doesn't depend
on many libraries, and here is the error showed at the end of the report:
==87482== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)
==87482==
==87482== 1 errors in context 1 of 2:
==87482== Conditional jump or move depends on uninitialised value(s)
==87482== at 0x4021881: strcmp (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x400ADAB: _dl_name_match_p (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x4008383: _dl_map_object (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x401A034: map_doit (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x4001488: _dl_catch_exception (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x40015AE: _dl_catch_error (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x401A51F: do_preload (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x401B2A6: handle_preload_list (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x401E0D2: dl_main (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x401993E: _dl_sysdep_start (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x401B04B: _dl_start (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x4019F17: ??? (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== Uninitialised value was created by a stack allocation
==87482== at 0x401B24A: handle_preload_list (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482==
{
<insert_a_suppression_name_here>
Memcheck:Cond
fun:strcmp
fun:_dl_name_match_p
fun:_dl_map_object
fun:map_doit
fun:_dl_catch_exception
fun:_dl_catch_error
fun:do_preload
fun:handle_preload_list
fun:dl_main
fun:_dl_sysdep_start
fun:_dl_start
obj:/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2
}
==87482==
==87482== 1 errors in context 2 of 2:
==87482== Conditional jump or move depends on uninitialised value(s)
==87482== at 0x4021881: strcmp (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x400AD84: _dl_name_match_p (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x4008383: _dl_map_object (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x401A034: map_doit (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x4001488: _dl_catch_exception (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x40015AE: _dl_catch_error (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x401A51F: do_preload (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x401B2A6: handle_preload_list (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x401E0D2: dl_main (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x401993E: _dl_sysdep_start (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x401B04B: _dl_start (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== by 0x4019F17: ??? (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482== Uninitialised value was created by a stack allocation
==87482== at 0x401B24A: handle_preload_list (in
/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2)
==87482==
{
<insert_a_suppression_name_here>
Memcheck:Cond
fun:strcmp
fun:_dl_name_match_p
fun:_dl_map_object
fun:map_doit
fun:_dl_catch_exception
fun:_dl_catch_error
fun:do_preload
fun:handle_preload_list
fun:dl_main
fun:_dl_sysdep_start
fun:_dl_start
obj:/remote/tools/Linux/2.6/1A/toolchain/x86_64-v23.0.8/lib/ld-linux-x86-64.so.2
}
==87482== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)
> But it looks like it is too early. Which means we might want to create a
> hardwire for it in coregrind/m_redir.c
Yes this happens very early in the dynamic library loading process, so even the
.so shared library provided by valgrind aren't loaded just yet (actually from
what I recall from my initial investigation months ago is that the compared
string came from the LD_PRELOAD variable set by valgrind to preload the
valgrind .so replacement containing strcmp and the likes.
We might want to start from scratch and use a new suppression file containing
just this specific case. For now in our toolchain we keep using my patch until
an official solution is pushed in the valgrind project.
Cheers,
Romain
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