Dear Paul,
Thank you for your e-mail and the lucid explanation.
I am sorry that I could not write to you earlier.
There was something wrong with my PC hardware and it took me quite a
while to re-install many software products I regularly use.
I will try to create a short sample. (The whole thunderbird software is
a gigantic problem.) But it may be difficult
since the source code is large and if the compiler's code generation is
history-sensitive, the problem may not be easy to re-create.
I will also check on the versions of tools that was used when the
problem was noticed.
Let me have a couple of hours to check the versions.
BTW, now I vaguely recall that there was an issue with DL-library
released many years ago by Debian regarding the
symbols for strcpy and friends. I can't recall the details now, but in
that instance, the lack of proper debug symbols made the
re-direction difficult(?) If my hazy memory is correct, the today's
case may be influenced by a similar issue, but I better collect the
versions so that someone in the know can experiment on their ends.
Back then, I think I created a wrapper that introduces the symbols for
strcmp and friends. But that was many years ago.
TIA
Chiaki
PS: For those curious enough to know the hardware issue, I wanted to
replace my Ryzen 1700 CPU with 16MB of L3 cache with
Ryzen 3700x with 32GB of cache, solely because I learned that
larger the cache, the valgrind running big program like thunderbird mail
client would fare better.
After a few years of use of 1700, I suspect the CPU is the limiting
factor. I like it.: it uses much less power than many other modern CPUs.
So it runs cool, and the PC is very silent without noisy fans.
Unfortunately, when I replaced the CPUs after carefully checking BIOS
version, etc. to make sure the CPU would run on the motherboard (yes, it
did. It runs linux without an issue at all,),
somehow Windows 10 Pro hosting my virtualbox running linux did not boot
any more after the replacement and
trashed my boot environment. Aargh.
In the end, I figured it was faulty AMD SATA driver which got installed
maybe in the last couple of years when I installed AMD's chip driver.
It did not cause a problem for Ryzen 1700 for the last few years, but
with 3700x, the boot fails due to it.
After the boot failure, even the safe mode fails to boot. Ugh.
I had to re-install windows and so had to re-install many applications
and such that I use for work and hobby. Oh, such is life.
But I am a happy camper now with the second hand Ryzen 3700x and hope to
run and find more of these valgrind issues of TB soon. The whole build
time from scratch got shorted from abot 90+ minutes to 60+ minutes. Not bad.
I have yet to figure out the shortening of TB's test suite execution
time. I am hampered with strange errors that I did not notice a few
months before. Maybe these are newly introduced errors, including the
one I reported, and I am analyzing whether I can simply suppress them or
investigate in detail.
On 2022/05/11 16:54, Floyd, Paul wrote:
Hi
Can you give us
the source of the small reproducer
the versions of Valgrind, Debian, GCC and glibc?
As you mention, functions like strncmp are often optimized to work on
multiple bytes at a time and to take advantage of the fact that memory
will always be allocated in a multiple of say 8 or 16 bytes. And what
happens sometime is that a function like strncmp will be replaced by
the compiler with something like __strncmp_avx128 or something like
that. If Valgrind doesn't recognize this it can't redirect it and do
error checking on it.
I would expect that the error message contain the name of the Valgrind
redirect, for instance
==22489== at 0x4033B7C: __strncmp_sse42 (vg_replace_strmem.c:712)
Si it seems to me that you have a redirection problem. For some reason
Valgrind is not seeing your strncmp when the client libc gets loaded
into memory.
A+
Paul
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